NTA Level 5 • Semester 2 • PST05210

Basic Pharmacognosy – Complete Full Notes

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UNITED REPUBLIC OF TANZANIA

Ministry of Health, Community Development, Gender, Elderly and Children

Facilitator Guide

Children – 20

Table of Contents

Background iii

Acknowledgment iv

Introduction vi

Abbreviations/Acronym viii

Session 1: Introduction to Pharmacognosy 1

Session 2: The Plant Cell 7

Session 3: Plant Tissues 14

Session 4: Plant Tissue Systems 23

Session 5: Morphology of the Roots 28

Session 6: Morphology of Stems 36

Session 7: Morphology of the Leaf 44

Session 8: Morphology of the Flower 52

Session 9: Morphology of the Fruit 58

Session 10: Morphology of the Seed 64

Session 11: Pharmaceutical Barks 69

Session 12: Cultivation of medicinal plants 74

Session 13: Collection, Processing and Storage of Medicinal Plants 83

Session 14: Extraction of Active Medicinal Principals from Natural Sources

Session 15: Adulteration of Medicinal Plants 97

Session 16: Introduction to Ergastic Substances 102

Session 17: Gum, Mucilage and Pectins 109

Session 18: Introduction to Alkaloids 115

Session 19: Classification, Uses and Extraction of Alkaloids 120

Session 20: Tropane Alkaloids 127

Session 21: Lobelia and Tobacco 133

Session 22: Quinoline Alkaloids 137

Session 23: Isoquinoline Alkaloids 141

Session 24: Indole and Imidazole Alkaloids 146

Session 25: Purine Alkaloids 153

Session 26: Proto alkaloids 158

Session 27: Introduction of Glycosides 162

Session 28: Cardiac Glycosides 166

Session 29: Anthraquinone Glycosides 172

Session 30: Introduction to Volatile Oils and Resins 177

Session 31: Alcoholic and Hydrocarbon Volatile Oils 183

Session 32: Ketonic and Aldehydic Volatile Oils 188

Session 33: Phenolic ether, Phenolic, Oxide and Ester Volatile Oils 194

Session 34: Introduction to Fixed oils and Fats 200

Session 35: Castor, Olive, Cod-liver and Peanut Oils 205

Session 36: Almond, Linseed, Coconut and Cottonseed Oils 210

Session 37: Fats 215

Session 38: Waxes 219

Background

There is currently an ever-increasing demand for pharmaceutical personnel

in Tanzania. This is due to expanding investment in public and private

pharmaceutical sector. Shortage of trained pharmaceutical human resource

contributes to poor quality of pharmaceutical services and low access to

medicines in the country (GIZ, 2012).

Through Public-Private-Partnership (PPP) the Pharmacy Council (PC) together

with Development Partners (DPs) in Germany and Pharmaceutical Training

Institutions (PTIs) worked together to address the shortage of human

resource for pharmacy by designing a project named “Supporting Training

Institutions for Improved Pharmaceutical Services in Tanzania” in order to

improve quality and capacity of PTIs in training, particularly of lower

cadre pharmaceutical personnel.

The Pharmacy Council formed a Steering committee that conducted a

stakeholder’s workshop from18th – 22ndAugust 2014 in Morogoro to initiate

the implementation of the project.

Key activities in the implementation of this project included carrying out

situational analysis, curriculum review and harmonization, development of

training manual/facilitators guide, development of assessment plan,

training of trainers and supportive supervision.

After the curricula were reviewed and harmonized, the process of developing

standardised training materials started through Writer’s Workshop approach.

The approach included a number of workshops for developing, reviewing,

editing and formatting the sessions of the modules.

The goals of writer’s workshops were to build capacity of tutors in the

development of training materials and to develop high-quality, standardized

teaching materials.

The training package for pharmacy cadres includes a facilitator guide,

assessment plan and practicum. There are 11 modules for NTA level 5 making

11 facilitator guides including one practicum guide.

Acknowledgment

The development of standardized training materials of a competence-based

curriculum for pharmaceutical sciences has been accomplished through

involvement of different stakeholders.

Special thanks go to the Pharmacy Council for spearheading the

harmonization of training materials in the pharmacy after noticing that

training institutions in Tanzania were using different curricula and train

their students differently.

I would also like to extend my gratitude to Christian Social Service

Commission (CSSC) for their tireless efforts to mobilize funds from

development partners (German Ministry of Industry and action medeor). It

is through the implementation of the Multi-Actors Partnership (MAP)

project, CSSC has been able to provide the financial and technical

support needed during the development of this training material.

Many thanks go to the Centre for Educational Development in Health Arusha

(CEDHA) experts on health material development and training who coordinated

the development of these module sessions particularly Ms. Diana H. Gamuya

for her commitment in coordinating and facilitating the planning and

development to its completion.

Particular acknowledgements are sent to Mr. Dickson Mtalitinya and Members

from the secretariat of National Council for Technical Education (NACTE)

for facilitating and providing their expertise to the success of this work.

It will be unfair if I will not recognize the efforts and contributions of

all CEDHA supportive staff that made this process a success; accountant,

secretary, drivers and printers

Finally, I very much appreciate the contributions of the tutors and content

experts representing PTIs, hospitals, and other health training

institutions. Their participation in meetings and workshops, and their

input in the development of this training manual/facilitators guide have

been invaluable.

These participants are listed with our gratitude below:

Ms. Elizabeth Shekalaghe Registrar, Pharmacy Council of

Tanzania

Health,MoHCDGEC

Dr. Catherine Jincen Acting Principal, CEDHA

Dr. Sungwa N. Kabissi Project Manager – MAP,

CSSC

Ms. Diana H. Gamuya CEDHA

Ms. Grace Mallange PC

Ms. Emily Mwakibolwa Pharmacy Council

Ms. Tumaini H. Lyombe MUHAS

Ms. Dilisi J. Makawia KSP

Director of Human Resources Development

Ministry of Health, Community Development, Gender, Elderly and Children

Introduction

Module Overview

This module content is a guide for tutors of Pharmaceutical schools for

training of students. The session contents are based on sub-enabling

outcomes and their related tasks of the curriculum for Technician Course in

Pharmaceutical Sciences. The module sub-enabling outcomes and their related

tasks are as indicated in the in the Technician Certificate in

Pharmaceutical Sciences (NTA Level 5) Curriculum

Target Audience

This module is intended for use primarily by tutors of pharmaceutical

schools. The module’s sessions give guidance on the time, activities and

provide information on how to teach the session. The sessions include

different activities, which focus on increasing students’ knowledge, skills

and attitudes.

Organization of the Module

The module consists of thirty eight (38) sessions; each session is divided

into several parts as indicated below:

• Session Title: The name of the session

• Total Session Time: The estimated time for teaching the session,

indicated in minutes

• Pre-requisites: A module or session, which needs to be covered before

teaching the session.

• Learning Tasks: Statements which indicate what the student is expected to

learn by the end of the session

• Resources Needed: All resources needed for the session are listed

including handouts and worksheets

• Session Overview: The session overview box lists the steps, time for each

step, the activity or method used in each step and the step title

• Session Content: All the session contents are divided into steps. Each

step has a heading and an estimated time to teach that step as shown in

the overview box. Also, this section includes instructions for the tutor

and activities with their instructions to be done during teaching of the

contents

• Key Points: Key messages for concluding the session contents at the end

of a session This step summarizes the main points and ideas from the

session, based on the learning tasks of the session

• Evaluation: The last section of the session consists of short questions

based on the learning tasks to check the understanding of students.

• Handouts: Additional information, which can be used in the classroom

while teaching or later for students’, further learning. Handouts are

used to provide extra information related to the session topic that

cannot fit into the session time. The students to study material on their

own and to refer to them after the session can use handouts. Sometimes, a

handout will have questions or an exercise for the participants including

the answers to the questions.

Instructions for Use and Facilitators Preparation

• Tutors are expected to use the module as a guide to train students in the

classroom and skills laboratory

• The contents of the modules are the basis for teaching and learning

dispensing.

• Use the session contents as a guide

• The tutors are therefore advised to read each session and the relevant

handouts and worksheets as preparation before facilitating the session

• Tutors need to prepare all the resources, as indicated in the resource

section or any other item, for an effective teaching and learning process

• Plan a schedule (timetable) of the training activities

• Facilitators are expected to be innovative to make the teaching and

learning process effective

• Read the sessions before facilitation; make sure you understand the

contents in order to clarify points during facilitation

• Time allocated is estimated, but you are advised to follow the time as

much as possible, and adjust as needed

• Use session activities and exercises suggested in the sessions as a guide

• Always involve students in their own learning. When students are

involved, they learn more effectively

• Facilitators are encouraged to use real life examples to make learning

more realistic

• Make use of appropriate reference materials and teaching resources

available locally

Preparation with Handouts and Worksheets

• Go through the session and identify handouts and worksheets needed for

the session

• Reproduce pages of these handouts and worksheets for student use while

teaching the session. This will enable students to refer to handouts and

worksheets during the session in the class. You can reproduce enough

copies for students or for sharing

• Give clear instructions to students on the student activity in order for

the students to follow the instructions of the activity

• Refer students to the specific page in the student manual as instructed

in the facilitator guide

Using Students Manual When Teaching

• The student manual is a document, which has the same content as the

facilitator guide, which excludes facilitator instructions and answers

for exercises.

• The student manual is for assisting students to learn effectively and

acts as a reference document during and after teaching the session

• Some of the activities included in facilitator guide are in the student

manual without facilitator instructions

Abbreviations/Acronym

CBET Competency Based Education Training

CBL Competency Based Learning

CEDHA Centre for Educational Development in Health Arusha

CSSC Christian Social Services Commission

CUHAS Catholic University of Health and Allied Sciences

DTLC District TB and Leprosy Coordinator

GDF Global Drugs Facility

GPA Grades per Annum

HTI Health Training Institution

KSP Kilimanjaro School of Pharmacy

MAP Multi-Actor Partnership

MOHCDGEC Ministry of Health Community Development Gender Elderly and

MSD Medical store department

MSD Medical Store Department

NACTE National Council for Technical Education

NTA National Technical Awards

NTLP National Tuberculosis and Leprosy Program

PC Pharmacy Council

PTI Pharmaceutical Training Institution

RAS Regional Administrative Secretary

RTLC Regional TB and Leprosy Coordinator

RUCU Ruaha Catholic University

SIBS Springs Institute of Business and Sciences

Session 1: Introduction to Pharmacognosy

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define pharmacognosy

• Explain the meaning of pharmacognosy

• Define common terminologies applied in pharmacognosy

• Identify uses of natural products

• Historical background of pharmacognosy

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD and laptop

SESSION OVERVIEW

|1 |05 |Presentation |Introduction, Learning Tasks |

|2 |15 |Presentation |Definition and Meaning of |

|3 |20 |Presentation |Common Terminologies Applied |

|4 |20 |Brainstorming |Uses of Natural Products |

|5 |40 |Presentation |Brief History of |

|6 |05 |Presentation |Key Points |

|7 |05 |Presentation |Evaluation |

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Definition and Meaning of Pharmacognosy (15 minutes)

• Pharmacognosy is a science which deals with the study of crude medicine

(or unprepared form) in substances obtained originally from natural

sources mainly plant, animal and minerals

• The word Pharmacognosy is derived from the Greek words

o "Pharmakon", meaning a drug or medicine and

o "gignosco" meaning to acquire a knowledge of

• It deals with scientific study of structural, physical, chemical and

sensory characters of crude drug obtained from plant, animal and mineral

sources.

• Some materials have no pharmacological action but have interest to

pharmacognosy e.g. natural fibres, flavouring and suspending agents,

colorants, disintegrants, stabilizers, filtering and supporting media

• Also other materials with natural associations with the subject are

poisonous, hallucinogenic plants, allergens, herbicides, insecticides and

molluscicides

STEP 3: Common Terminologies Applied in Pharmacognosy (20 minutes)

• Drug

o Is a natural or synthetic substance used in the treatment, cure,

prevention, or diagnosis of disease or used to otherwise enhance

physical or mental wellbeing

o Drugs should be included in the official pharmacopoeia

• Crude drugs

o Are harvested (i.e. dried) plant or animal sources which

pharmaceutically or medicinally useful products, and before they

undergo extensive processing or modification

o A crude drug can be

▪ An entire organism (plant, animal, organism

▪ A part of an organism (a leaf or flower of a plant, an isolated

gland or other organ of an anima

▪ An extract or an exudate of an organism

o An isolated pure compound

o Sources of Crude Drugs:

▪ Plant sources, e.g. Senna

▪ Animal sources, e.g. honey

▪ Minerals sources, e.g. talc

• Natural Product

o It is a chemical compound or substance produced by a living

organism found in nature that usually has a pharmacological or

biological activity for use in pharmaceutical drug discovery and

drug design.

• Ethnobotany

o Is the study of the relationship between people and plants, field

includes studying plants as medicines, alternative methods for healing,

as wild foods, as agricultural crops; modes of transportation; as

clothing and in the religious ceremonies.

• Ethnopharmacology

o Ethnopharmacology is the scientific study correlating ethnic groups,

their health, and how it relates to their physical habits and

methodology in creating and using medicines

STEP 4: Uses of Natural Products (20 minutes)

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What are the uses of natural products? |

| |

|ALLOW few students to respond |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARISE by using the content below |

• As medicines for the treatment of a wide range of diseases, e.g.

morphine, atropine, digoxin, hormones, antibiotics

• As pharmaceutical aids in pharmaceutical industry e.g. suspending &

emulsifying agents, suppository bases, binders, sweetening and colouring

agents

• In cosmetics as flavouring and colouring agents

• In culture media for the propagation of microorganisms in microbiology

laboratories & biotechnology.

• General uses e.g. in food industries: as dusting powders, as indicators

and in perfumery.

STEP 5: Brief History of Pharmacognosy (50 minutes)

• The history of Pharmacognosy is synonymous with the history of medicine

which originates in the health-related activities of the most primitive

race of the remote past

• Description of history of pharmacognosy is (therefore) embedded in the

history of natural products in medicine

• They acquired knowledge of medicinal properties of plants in the

following ways

o By guesswork or trial and error while searching food.

o By superficial resemblance between plant parts and affected

organs.

o By accidental discovery.

• The history of pharmacognosy can be divided into;

o The Ancient Egyptian Period

o The Babylonians

o Old Indian medicine

o The old Chinese medicine

o The Greek and Romans

o The Arabic Era

o The 18th Century Pharmacognosists

o The 19th Century Pharmacognosy

o The 20th Century Pharmacognosy

STEP 6: Key Points (5 minutes)

• Pharmacognosy is a science which deals with the study of crude medicine

(or unprepared form) in substances obtained originally from natural

sources mainly plant, animal and minerals

• Sources of crude drugs include plants, animals and minerals

• Knowledge of medicinal properties of plants is acquired by guesswork or

trial and error while searching for food, by superficial resemblance

between plant parts and affected organs and by accidental discovery

STEP 7: Evaluation (5 minutes)

• What is crude drug mean?

• What are the uses of natural products?

• What are the major discoveries were made in pharmacognosy in the 20th

century?

STEP 8: Assignment (10 minutes)

|Activity: Take home Assignment (10 minutes) |

| |

|DIVIDE students in groups or individual. |

| |

|ASK the students to work on the following assignment |

| |

|List sources and uses of active principals from minerals |

| |

|ALLOCATE time for students to do the assignment and submit |

| |

|REFER students to recommended references |

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 2: The Plant Cell

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Explain structure of a plant cell

• List organelles of the plant cell

• List functions of plant cell organelles

• Explain the plant cell wall

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD and laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Introduction to Plant Cells (25 minutes)

|Activity: Buzzing (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What is a plant cell? |

| |

|ALLOW few students to respond? |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARISE by using the content below |

[pic]

• A plant cell is the structural unit of the plant body

• The plant cells consist of internal and external structures

• The internal structures (organelles) include;

o The Nucleus

o Nucleolus

o Centrosome

o Ribosomes

o Rough Endoplasmic Reticulum

o Smooth Endoplasmic Reticulum

o Golgi Complex (Golgi apparatus or Golgi body)

o Mitochondria

o Plastids

o Proplastids

o Etioplasts

o Chloroplasts

o Chromoplasts

o Leucoplasts

▪ Amyloplasts

▪ Elaioplasts

▪ Proteinoplasts

▪ Statoliths

o Nucleoids

o Vacuoles

• The external structures are mainly the cell wall

STEP 3: Internal Structures of a Plant Cell (60 minutes)

|Activity: Brainstorming (5 minutes) |

|Ask students to brainstorm on the following question: |

| |

|What are the functions of these organelles? |

| |

|ALLOW few students to respond? |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARISE by using the content below |

• The Nucleus

o Spherical body containing a nucleolus

o Surrounded by the nuclear membrane

o Contains DNA (genetic material in chromosomes)

• Nucleolus

o An organelle within the nucleus where ribosomal RNA is produced

o It controls many of the functions of the cell (by controlling protein

synthesis)

• Centrosome

o It is a small body located near the nucleus that forms and

organizes microtubules

o Microtubules are important in cell division (mitosis)

• Ribosomes

o Are small organelles composed of RNA-rich cytoplasmic granules that are

sites of protein synthesis

• Endoplasmic Reticulum

o Endoplasmic reticulum is a system of interconnected, membranous,

infolded and convoluted sacks located in cytoplasm (the ER is

continuous with the outer nuclear membrane)

o It transports materials through the cell and produces proteins

o Smooth Endoplasmic Reticulum are smooth (i.e. no ribosomes on surface)

▪ Contains enzymes and produces and digests lipids (fats) and

membrane proteins

• Golgi Complex: (i.e. Golgi apparatus or Golgi body)

o Is a flattened, layered, sac-like organelle that looks like a stack of

pancakes, located near the nucleus

o It packages and transports materials (proteins and carbohydrates) to

different locations inside/outside cell

• Mitochondria

o Spherical to rod-shaped organelles with a double membrane that

generates energy for the cell

• Plastids

o Are structures responsible for photosynthesis, storage of products like

starch and for the synthesis of many classes of molecules such as fatty

acids etc. needed as cellular building blocks and/or for the function

of the plant. There several types; proplastids, etioplasts,

chloroplasts, chromoplasts, leucoplasts and leucoplasts specialized for

different functions in the plant body.

• Vacuoles

o Are regions bound by membrane and filled with cell sap and surrounded

by the tonoplast

o In mature living cells may compose 90 – 95% of cell volume

o Storage site for variety of (ergastic) substances such as:

▪ Water

▪ Enzymes and other proteins

▪ Water-soluble pigments (e.g. red and blue anthocyanins)

▪ Toxic alkaloids, tannins

▪ Lipids

▪ Crystals (calcium oxalate, calcium carbonate, silicon dioxide)

▪ Organic acids (oxalate, malate)

STEP 4: The Plant Cell Wall (20 minutes)

• The plant cell wall is heterogeneous structure composed of layers

(lamellae)

o Each cell secretes its own wall

o Junction between the walls is the Middle lamella

o Cell wall is penetrated by plasmodesmata connecting neighbouring cells

o Cell walls are primarily composed of sugar polymers i.e.

polysaccharides

o The architecture, mechanics, and function of plants depend crucially on

structure of cell wall

• Functions

o Regulates cell volume by limiting protoplast size preventing cell

rupture

o Determines cell shape

o Involved in cell-cell adhesion; provide support to cells and whole

plant

o Forms specialized structures for:

▪ Transport of water and nutrients

▪ Defense against bacterial and fungal attack

▪ Reproduction

• Composition of Cell Walls

o Primary cell wall:

▪ Which is the only cell wall in growing and dividing cells

▪ First formed cell wall

▪ Composed of cellulose embedded in matrix of hemicellulose and

pectin, cellulose molecules: Unbranched glucose chains and

hemicellulose – a highly branched molecule of sugars and sugar

derivatives

▪ Pectins:

• Are highly branched negatively charged polysaccharides rich in

galacturonic acid

• Give compressive strength to the cell wall

• Modulate porosity, pH, and ion concentrations within the wall

o Primary wall/Middle Lamellae

▪ Primarily associated with hemicelluloses and pectins

▪ Water is 65% of weight of cell wall

o Secondary Cell Wall

▪ Many plant cells synthesize secondary walls after the cell has

completely elongated

▪ Secondary wall is deposited by protoplast inside primary wall after

cell stops growing

▪ Composition of secondary wall:

• Cellulose, hemicellulose and pectin

• Lignin

• Stronger than cellulose

• There substances found on the surface of the cell wall. These include

cuticle waxes, suberin and minerals

STEP 5: Key Points (5 minutes)

• The main reason of studying the pant cell is to understand parts involved

in synthesis and storage of drugs

• The plant cell is the structural unit of the plant

• The plant cell is composed of internal and external structures

• The cell wall is a rigid external layer of the plant cell that protects

the cell

STEP 6: Evaluation (5 minutes)

• Mention organelles found in a plant cell

• What is the composition of the primary cell wall?

• What are the functions of the Golgi apparatus?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 3: Plant Tissues

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define Tissue

• Classify Plant Tissues

• Explain Properties of the Plant Tissues

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LDC projector and laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Plant Tissues and Their Classification (30 minutes)

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|Define a plant tissue |

| |

|ALLOW few students to respond? |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARISE by using the content below |

• A plant tissue may be defined as a group of cells, which are similar in

origin, form and function or as a group of dissimilar cells that perform

a common function. E.g. phloem elements conduct food

• The simple type of plant body is unicellular, in such form; the single

cell performs all the vital functions of life. It grows, prepares food,

undergoes metabolism, reproduces and completes its span of life

• In higher plants, root, stem, leaves and flowers carry out different

functions. Due such division of labour, the cells of the plant are

differentiated to form different tissues. The different tissues perform

different functions

• Tissues can be classified into main two types:

o Meristematic tissue and

o Permanent tissue

Scheme below Shows Classification of Plant Tissues

Plant Tissue

Meristematic Permanent

(Mature cells incapable of division) (Cells are capable

of division)

Simple Complex

(Single type of cells) (More than

one type of cells)

Parenchyma Collenchyma Sclerenchyma Xylem

Phloem

Xylem vessel Sieve

tube

Tracheids Companion

Cells

• Meristematic Tissue (Cells are capable of division)

o A meristematic tissue (meristos = divisible) is a group of identical

cells that are in a continuous state of division

o Some cells produced by meristematic tissue stop dividing and acquire

certain changes (differentiation) to become permanent tissues of the

plant

• Based on location on the plant, the meristem is divided into three

types:

o Apical meristem

▪ Found at the tips of roots, stem and branches

▪ Functions to increase length of these parts

▪ Divided into three zones

• Protoderm – form epidermal tissue

• Procambium – form primary vascular tissues

• Ground meristem – form cortex and pith

o Intercalary meristem

o Found in the nodal region, prominently in monocotyledons, e.g.

grasses.

o It is derived from the apical meristem

o Elongates the internodes

o Lateral meristem

o Found along the longitudinal axis of stem and root

o E.g. Vascular cambium and cork cambium (phellogen)

o Produces secondary permanent tissues

o Increase thickness of stem and root

• Permanent Tissue (Mature cells incapable of division)

o Are tissues that have temporarily or permanently lost the power to

divide

o The cells formed by the apical meristem are differentiated into

different types of permanent tissues

• Based on the constituent cells, the permanent tissue is classified

into two types: –

o Simple tissue

▪ Tissues made up of cells with similar structure and

function

▪ Classified into;

• Parenchyma,

• Collenchyma and

• Sclerenchyma

o Complex tissue

▪ A tissue made up of several kinds of cells but all of them

function together as a single unit

▪ Classified into;

• Xylem tissue

o Xylem (Greek word ‘xylos’= wood)

o Xylem is made up of four kinds of cells

▪ Tracheids

▪ Vessels or tracheae,

▪ Xylem fibres and

▪ Xylem parenchyma

• Phloem tissues

o Phloem is composed of four types of cells:

▪ Sieve elements,

▪ Companion cells,

▪ Phloem parenchyma and

▪ Phloem fibres

• Companion cells are present only in

angiosperms

STEP 3: Properties of Plant Tissues (75 minutes)

• Characteristics of Meristematic Tissues

o May be round, oval, polygonal or rectangular in shape

o Are closely arranged without intercellular spaces

o Have dense cytoplasm with large nuclei.

o Have smaller vacuoles, scattered throughout the cytoplasm.

o Their cell walls are thin, elastic and made up of cellulose

• Characteristics of Parenchyma Tissues

o Generally present in all plant organs

o Form the ground tissue in a plant

o Is living tissue made of thin walled cells

o Is the precursor of all the other tissues

o The cell wall is made up of cellulose

o Parenchyma cells may be oval, spherical, rectangular, cylindrical or

stellate

o Parenchyma is of different types

o In green parts of the plants, the parenchymatous cells have

chloroplasts; they are called chlorenchyma. Its important function is

photosynthesis

• Characteristics of Collenchyma Tissues

o Is a living tissues generally occurring in the dicot stems in two or

more layers below the epidermis, these layers form the hypodermis

o It also occurs in petiole and pedicel

o The cell wall is unevenly thickened, thickening is confined to the

corners of the cells

o Collenchyma strengthen young organs

• Characteristics of Sclerenchyma Tissues

o Is a dead tissue; lacks protoplasts

o The cells are very thick i.e. have lignified secondary walls (woody)

o Sclereids

▪ Sclereids re shorter, fibers are longer

▪ Sclereids have numerous pits, fibers few pits

▪ Sclereids are dead cells varying greatly in shape and

thickness

▪ Cell wall is very thick due to lignification

▪ Provide rigidity of the seed-coat

o Fibers

▪ Are dead cells (at maturity), very long and narrow with pointed

ends, with simple pits

▪ The secondary wall is evenly thickened with lignin

▪ Are supporting tissues, provide mechanical strength to plants and

protect from strong winds

▪ Fibers found in seed coat of some seeds are called surface fibers.

E.g. cotton.

• Characteristics of Xylem Tissues

o Is a complex tissue mainly responsible for conduction of water and

mineral salts from roots to other parts of the plant

o Primary xylem is formed from procambium,

o Secondary xylem: from vascular cambium

o Earlier formed xylem elements = protoxylem

o Later formed xylem elements = metaxylem

o Tracheids

▪ are imperforate cells with bordered pits on end walls arranged one

above the other and their roles are to conduct water and mineral

salts in in gymnosperms and pteridophytes and also to provide

mechanical support to these plants

o Vessels or Tracheae

▪ Are perforated at the end walls

▪ The lumen is wider than that of tracheids

▪ The perforated plates at the end wall separate the

vessels

▪ Arranged parallel to the long axis of the plant body

▪ When entire end wall is dissolved, a single pore is formed at the

perforation plate

▪ Vessels are chief water conducting elements in

angiosperms

▪ Are absent in pteridophytes and gymnosperms

▪ Their function is to conduction of water and minerals and provide

mechanical support to the plant

[pic]

• Xylem Fibers

o The fibres of sclerenchyma associated with the xylem are known as xylem

fibres

o Give additional mechanical support to the plant body.

o Present both in primary and secondary xylem

o Xylem fibres are dead lignified cells

• Xylem Parenchyma

o The parenchyma cells associated with the xylem are known as xylem

parenchyma

o Is the only living tissue in the xylem

o Their functions are to store food reserves in the form of starch and

fat and assist in conduction of water

• Phloem Tissues

o Conducts food materials to various parts of the plant

o Primary phloem: formed from pro-cambium of apical meristem

o Secondary phloem: vascular cambium

• Sieve Elements:

o Sieve elements are the conducting elements of the phloem

o Their end walls are transverse or oblique

o End wall contains pores and look like a sieve, hence sieve plate

o Sieve elements are arranged one above the other and form vertical sieve

tubes

o In matured sieve tube, nucleus is absent

• Companion cells

o Are thin-walled, elongated, specialized parenchyma cells, associated

with the sieve elements

o Have cytoplasm and a prominent nucleus.

o Present only in angiosperms and absent in gymnosperms and pteridophytes

o Assist sieve tubes in conduction of food materials

o Phloem Parenchyma

o Parenchyma cells associated with phloem

o Are living cells and store starch and fats

o Also contain resins and tannins in some plants

o Present in all pteridophytes, gymnosperms and dicots

o Usually absent in monocots

o Phloem fibres

o The fibers of sclerenchyma associated with phloem are called phloem

fibers or bast fibers

o They are narrow, vertically elongated cells with very thick walls and a

small lumen (the cell cavity)

o Are the only dead tissue in the phloem

o Strengthening and supporting cells

STEP 5: Key Points (5 minutes)

• A tissue is a group of cells, which are similar in origin, form and

function

• A tissue may also be defined as a group of dissimilar cells that perform

a common function. E.g. phloem elements conduct food

• Meristematic tissues are capable of dividing to form new cells

• Permanent tissues have lost the power to divide and cannot form new cells

STEP 6: Evaluation (5 minutes)

• What are the properties of parenchyma?

• What are the characteristics of meristematic cells?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 4: Plant Tissue Systems

Total Session Time: 60 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define Tissue Systems

• Categorize Tissue Systems

• Explain Tissue Systems

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Tissue Systems and Their Categorization (45 minutes)

|Activity: Small Group Discussion (15 minutes) |

| |

|Ask students to work in groups on the following question: |

|How do you categorize tissues system? |

| |

|ALLOW few students to respond |

| |

|WRITE their responses on the flip chart/board |

| |

|CLARIFY and SUMMARISE by using the content below |

• Tissue systems are groups of tissues performing a similar function

irrespective of its position in the plant body

• Tissues systems are:

o Dermal (Epidermal) tissue system,

o vascular tissue system and

o Fundamental (Ground) tissue system

o Epidermal Tissue System:

▪ In leaves there are guard cells

▪ Chloroplasts: present only in the guard cells of the

epidermis

▪ Other epidermal cells usually do not have chloroplasts

▪ Outer wall of epidermis is usually covered by cuticle

▪ The Stoma

• Stoma is a minute pore surrounded by 2 guard cells

• The stomata occur mainly in the epidermis of leaves

• Trichomes

o Are unicellular or multicellular appendages originating from the

epidermal cells

o Trichomes may be branched or unbranched

• Functions of Epidermal Tissue System

o Excessive loss of water due to the presence of cuticle

o Epidermis protects the underlying tissues

o Stomata are involved in transpiration and gaseous exchange

o Trichomes help dispersal of seeds and fruits

o Root hairs absorb water and mineral salts from the soil

• Vascular Tissue System

o Consists of xylem and phloem

o Elements of xylem and phloem are always organized in groups called

vascular bundles

o In dicot stems, the vascular bundle consists of cambial tissue in

between xylem and phloem (i.e. Open vascular bundle)

o In monocot stem, cambium is absent in the vascular bundle (i.e. closed

vascular bundle)

o In roots, xylem and phloem are arranged in an alternate manner on

different radii, this is called radial arrangement

o In stems and leaves, xylem and phloem are arranged at the same radius

and form a vascular bundle together (i.e. Conjoint vascular bundle)

o Conjoint vascular bundles may be;

▪ Collateral

• Xylem and phloem on same radius, phloem is outward

▪ Bicollateral

• Phloem on outer and inner sides of xylem

o Concentric vascular bundle

o Either phloem or xylem surrounds the other completely

o It is amphicribral if the phloem completely surrounds the xylem

o It is amphivasal if the xylem completely surrounds the phloem

• Ground or Fundamental Tissue System

o Form the main body of the plants (bulk of plant)

o Includes all the tissues except epidermis and vascular bundles

o In monocot stem, ground tissue system is a continuous mass of

parenchymatous tissue in which vascular bundles are found scattered

i.e. ground tissue is not differentiated into cortex, endodermis,

pericyclic and pith.

o In the leaves, ground tissue is made of chlorenchyma tissues forming

the mesophyll

o These cells are arranged in a single layer without intercellular spaces

o Cells in the pith generally store starch, fatty substances, tannins,

phenols, calcium oxalate crystals, etc.

• Secretory Tissues

o Cells or organizations of cells that produce a variety of secretions

o Secreted substance may remain deposited within secretory cell itself or

may be excreted (released from the cell)

o The substance maybe excreted to the surface of the plant or into

intercellular cavities or canals

o Some of the secretions are waste products e.g. resins, rubber, tannins

and various crystals

o Other secretions are useful in plants e.g. enzymes and hormones.

o Secretory structures may be single cells or group of cells (glands)

o Oil cells occur in ginger, pepper, mace, cardamoms, cinnamon and cassia

o The latex cells (produce latex) are found e.g. in Cannabis sativa

STEP 3: Key Points (5 minutes)

• Tissue systems are groups of tissues performing a similar function

irrespective of its position in the plant body

• Tissues systems are divided into dermal (epidermal) tissue system,

vascular tissue system and fundamental (Ground) tissue system

• Epidermal tissue system covers surfaces of the plant body

• Vascular tissue system forms the transport system of the plant

• The ground tissue system supports the vascular and the dermal tissue

systems

STEP 4: Evaluation (5 minutes)

• What are the functions of epidermal tissue system?

• What is the stoma?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 5: Morphology of the Roots

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Explain Roots

• Classify Roots

• Differentiate Monocotyledon from Dicotyledon

• Functions of the Roots

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing

STEP 2: Characteristics of Plant Roots (25 minutes)

• The root constitutes the underground part of the plant axis.

• It is an organ of the plant that typically lies below the surface of

the soil

• Externally the root has root hairs which aid in absorption of water

minerals

• Roots can be classified in three main categories:

o Tap roots

▪ One large vertical root

▪ Also produces many small lateral or branch roots

▪ These are common in dicotyledonous plants

o Fibrous roots

▪ Mat of thin roots that spread out

▪ Made up of many thread-like members of more or less equal length

▪ These are common in monocotyledonous plants

o Adventitious roots

▪ Form on any plant part other than the roots

▪ They commonly occur in grasses

• General Internal structure of the root;

[pic]

• Functions of the Roots

o The following are the functions of the roots

▪ Roots support (anchorage) the plant in the soil (or other media in

which the plant is growing)

▪ Absorption of water and other nutrients from the soil

▪ Storage of food

▪ Transport minerals and water to other parts of the plant

STEP 3: Anatomy of the Monocotyledonous Roots (30 minutes)

• Internal structure of monocot roots shows the following tissue systems

o Epiblema or rhizodermis

o Cortex and

o Stele

Fig 5.1: Internal Structure of the Monocotyledonous Root

[pic]

• The Rhizodermis or Epiblema

o Outermost layer of the root

o Single row of parenchyma cells, no intercellular space

o Stomata and cuticle are absent

o Root hairs are always unicellular

o The key function of rhizodermis is protection of the inner

tissues of the root

• The Cortex

o The cortex is made of only one type of tissue (parenchyma)

o Has many layers of parenchyma cells with lot of intercellular spaces

o Cortical cells are generally oval or rounded in shape; chloroplasts are

absent

o The cells are living and possess leucoplasts

o The inner most layer of the cortex is endodermis and is composed of

single layer of barrel shaped parenchymatous cells

o The function of cortical cells is storage

o Endodermis (innermost layer of cortex) forms a complete ring around the

stele (tissues inside endodermis)

o There is a band-like structure made of (thickened with) suberin present

in the radial and transverse walls of the endodermal cells

o The band is called Casparian strips

o The endodermal cells opposite to the protoxylem elements, are thin-

walled without Casparian strips

o These cells are called passage cells and their function is to transport

water and dissolved salts from the cortex to the xylem

o Water cannot pass through other endodermal cells due to Casparian

strips (blocking effect)

o The main function of Casparian strips in the endodermal cells is to

prevent the re-entry of water into the cortex once water enters the

xylem tissue

• Vascular System (Stele)

o Vascular tissues are in radial arrangement with many protoxylem

groups

o This arrangement of xylem is called polyarch and the xylem is in

exarch condition

o The tissue present between the xylem and the phloem, is called

conjunctive tissue

• The Pith

o The central portion

o It consists of thin walled parenchyma cells with intercellular

spaces

o These cells are filled with abundant starch grains

STEP 4: Anatomy of the Dicotyledonous Roots (30 minutes)

• The Dicotyledonous Root

o Structure of a Dicotyledonous Root

[pic]

• Rhizodermis or Epiblema

o Outermost layer aka rhizodermis (epidermis in stems) made of a single

layer of parenchyma cells which are arranged compactly without

intercellular spaces, with no stomata or cuticle

o Root hair is always single celled

o Protects inner tissues of the root

• The Cortex

o Consists of only parenchyma cells loosely arranged with intercellular

spaces to make gaseous exchange easier

o These cells may store food reserves

o The cells are oval or rounded in shape

o Sometimes are polygonal due to mutual pressure

o Cortical cells are devoid of chloroplasts but starch grains are stored

in them

o The cortical cells also possess leucoplasts

o Inner most layer of the cortex is endodermis

o Endodermis is made up of single layer of barrel shaped parenchymatous

cells

o Stele is completely surrounded by the endodermis

o The radial and the inner tangential walls of endodermal cells are

thickened with suberin

o Casparian strips

o Casparian strips are absent in the endodermal cells located opposite to

the protoxylem elements

o These thin-walled cells without Casparian strips are called passage

cells through which water and mineral salts are conducted from the

cortex to the xylem elements

o Water cannot pass through other endodermal cells due to the presence of

Casparian thickenings

• The Stele

o Include all the tissues present inside endodermis

o The stele includes pericycle and vascular tissues

▪ The Pericycle

• Pericycle is generally a single layer of parenchymatous cells found

inner to the endodermis

• It is the outermost layer of the stele

• Lateral roots originate from the pericycle

• Thus, the lateral roots are endogenous in origin

▪ The Vascular Tissues

• Vascular tissues are in radial arrangement

• Xylem and phloem are separated by a conjunctive tissue

• If conjunctive tissue is composed of parenchymatous tissue then,

the xylem is in exarch condition

• If number of protoxylem points is four, then, the xylem is called

tetrarch

• Each phloem patch consists of sieve tubes, companion cells and

phloem parenchyma

• Metaxylem vessels are generally polygonal in shape but in monocot

roots they are circular

STEP 5: Difference between Monocot and Dicot Roots (20 minutes)

|Activity: Small Group Discussion (15 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

|What are the differences between monocot root and dicot root? |

| |

|ALLOW students to discuss for 15 minutes |

| |

|ALLOW few groups to present and the rest to add points not |

|mentioned |

| |

|CLARIFY and SUMMARIZE by using the contents below |

[pic]

STEP 6: Key Points (10 minutes)

• The root is an organ of the plant that typically lies below the surface

of the soil

• Three basic types of roots include; tap roots, fibrous roots and

adventitious roots

• Anatomy of the root consists of a series of concentric rings of different

tissues namely the epidermis, the cortex, the endodermis, the pericyle

and the vascular system

STEP 7: Evaluation (5 minutes)

• What is a root

• What are the layers composing the internal structure of the dicot root?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 6: Morphology of Stems

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Introduction of the Stem

• External Structure of the Stem

• Differentiate Dicot from Monocot Stem

• Functions of the Stem

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Introduction to Stems and External Features (20 minutes)

• Stem is the axis of the plant other than the root

• In most plants stems are located above the soil surface but some plants

have underground stems

• Functions of the stem

o Stems support the leaves and other structures e.g. flowers,

fruits

o Stems are used for vegetative reproductive i.e. cuttings

o Stems position leaves to receive maximum sunlight

o Stems determine size and shape of the plant

o Facilitates movement of water, minerals, and manufactured

food in the plant

o Some stems carry out photosynthesis

o Stores foods

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What are the external structures of the stem? |

| |

|ALLOW few students to respond? |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARISE by using the content below |

• External structures of the stem

o Internodes: distances separating one node from

another

o Nodes: Points at which leaves are attached

o Lenticels: Breathing pores

o Buds: Growth of shoot

o Terminal or apical but, at tip of plan

o Axillary bud in nodes on stem

o Bud scale scars: Indicate where terminal bud has been located previous

year

o Leaf scars:

o Show where leaf was attached

• Internal structures of the stem

o Usually consist of three tissues, Dermal tissue, Ground

tissue and Vascular tissue

o The dermal tissue

▪ Covers outer surface of stem and usually functions to waterproof,

protect & control gas exchange

o The Ground tissue

▪ Mainly of parenchyma cells and fills in around the vascular tissue,

sometimes functions in photosynthesis

o The Vascular tissue

▪ Provides long distance transport and structural support

▪ Arrangement varies widely among plant species

STEP 3: Internal Structures of the Dicot Stem (35 minutes)

• Internal structure of dicotyledonous stem consists of Epidermis, Cortex

and Stele.

o Epidermis

▪ It consists of a single layer of parenchymatous rectangular cells

▪ Epidermal cells are compactly arranged without intercellular spaces

▪ Epidermis is covered on the outside by cuticle made up of waxy

substance

▪ The cuticle checks/controls transpiration

▪ Stomata may be present at irregular intervals

▪ A large number of multicellular hairs occur on the epidermis

o Cortex

▪ Cortex lies below the epidermis

▪ The cortex is differentiated into three zones

▪ The first zone (Hypodermis)

• Lies below the epidermis, consists of a few layers of

collenchyma cells

▪ The second zone

• Lies inner to the hypodermis

• Consists of a few layers of chlorenchyma cells

• Some resin ducts also occur in this zone

▪ The third zone

• Consists of parenchyma cells

• The innermost layer of the cortex is the endodermis

• Made of barrel shaped cells arranged compactly without

intercellular spaces

• Rich in starch grains, hence “starch sheath”

• In most dicot stems no casparian strips

[pic]

o The Stele

▪ In the central part of the stem inner to the endodermis

▪ It consists of pericycle, vascular bundles and pith

▪ Vascular bundles are arranged in a ring around the pith

• Pericycle

o Layers of cells between endodermis and vascular bundles

• Vascular Bundles

o Consist of xylem, phloem and cambium

o Xylem and phloem in stem occur together to form the vascular

bundles

o These vascular bundles are wedge shaped

o The vascular bundle is conjoint, collateral, open and endarch

o Phloem

• Consists of sieve tubes, companion cells and phloem

parenchyma

• Phloem conducts organic food materials from the leaves to

other parts of the plant body

o Cambium

• Consists of brick shaped and thin walled meristematic

cells

• Form new cells during secondary growth

o Xylem

• Consists of xylem fibres, xylem parenchyma, vessels and

tracheids

• Vessels are thick walled and arranged in a few rows

• Conducts water and minerals from the root to the other

parts of the plant body

• Pith (medulla)

o It is the large central portion of the stem

o It is composed of parenchyma cells with intercellular spaces

o The pith extends between the vascular bundles and form primary

medullary rays

o These extensions of the pith between the vascular bundles are

called

o It stores food

STEP 4: Internal Structures of the Monocot Stem (30 minutes)

• Internal structure of monocotyledonous stem consists of:

o Epidermis,

o Hypodermis,

o Ground tissue and

o Vascular bundles

▪ Epidermis

• It is the outermost layer of the stem made up of single layer of

parenchymatous cells and covered with a thick cuticle in some

plants

• Consists of few stomata

▪ Hypodermis

• Is made of few layer of sclerenchymatous cells lying below the

epidermis

• This layer gives mechanical strength to the plant

▪ Ground Tissue

• Consists of cells inner to the hypodermis

• Is not distinguished into zones like the dicot stem

• The cells contain reserve food material e.g. starch

• Contains the vascular bundles

• Carry out gaseous exchange function

▪ Vascular Bundles

• Vascular bundles are scattered in the ground tissue

• The vascular bundles are conjoint, collateral, endarch and

closed

• Vascular bundles are skull shaped

• Forms the woody part of the plant

STEP 5: Differences between Dicot and Monocot Stems (20 minutes)

|Activity: Small Group Discussion (10 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

| |

|What are the differences between monocot and dicot stems? |

| |

|ALLOW students to discuss for 10 minutes |

| |

|ALLOW few groups to present and the rest to add points not |

|mentioned |

| |

|CLARIFY and SUMMARIZE by using the contents below |

[pic]

STEP 6: Key Points (10 minutes)

• Stem is the part of both the flowering and nonflowering plants that is

usually above the ground, and in some plants below the ground. The stem

supports the leaves

• External features of the stem include presence of nodes, internodes,

lenticels, buds, leaf scars and bud scales

• Internally the stem is made up of layers of cells differentiated into

various function of support, storage, transport and photosynthetic in

some plants

STEP 7: Evaluation (5 minutes)

• What are the functions of the stem?

• What are the external structures of the stem?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 7: Morphology of the Leaf

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define a leaf

• List external structures of a leaf

• List internal structures of a leaf

• Explain the anatomy of a leaf

• Explain the criteria used in classification of leaves

• Explain the pharmacognostic importance of leaves

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Introduction to Plant Leaves (15 minutes)

|Activity: Buzzing (5 minutes) |

| |

|ASK students to pair up and buzz on the following question for 2 |

|minutes |

| |

|What is a leaf? |

| |

|ALLOW few pairs to respond and let other pairs to add on points not|

|mentioned |

| |

|WRITE their response on the flip chart/board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• A leaf is a plant organ that is found above the ground and is specialized

for photosynthesis

• The leaf is typically flat and thin

• Functions of the leaf

o Provides for transpiration and guttation

o Storage of food and water

• The leaf consists of a petiole, a lamina (or the leaf blade),

and stipules

o Petiole

▪ Attaches the leaf to the stem

▪ Some leaves are directly attached to the stem without a petiole

o The lamina

▪ Is flat and offers surface for trapping sunlight for photosynthesis

STEP 3: Internal Structures of a Plant Leaf (40 minutes)

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What are the internal structures of the plant leaf? |

| |

|ALLOW few students to respond? |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• The leaf is made up of three tissue systems (Dermal, Ground and Vascular)

• The dermal tissue system consists of lower and upper epidermis

• The ground tissue system is found between the epidermal layers of leaf

o Epidermis

▪ In dicot leaves, the epidermis is dorsiventral

▪ Generally, the epidermis is made up of a single layer of cells

that are closely packed and covered with a cuticle

▪ The epidermal tissue is made up of;

• Epidermal cells

• Guard cells

• Subsidiary cells

• Epidermal trichomes

o Epidermal cells

▪ Epidermal cells are the most numerous, largest, and

least specialized

▪ Epidermal cells are more elongated in the leaves of

monocots than in dicots

o Guard cells

▪ Consist of a pair of bean- shaped cells surrounding the

stoma

▪ They contain chloroplasts

▪ Other epidermal cells do not contain chloroplasts

o Subsidiary cells

▪ They are 2 to 4 cells that surround the stoma

▪ They do not contain chloroplasts

o The epidermal layer consists of stomata

▪ The stomata are part of a stoma complex which consists of

a pore surrounded on each side by guard cells and subsidiary

cells

▪ The stoma complex regulates the exchange of gases and

water vapour between the outside air and the interior of the

leaf

▪ There are more stomata over the abaxial that the adaxial

epidermis.

• Main function of the epidermis is to protect inner tissues

Figure 7.1: Transverse Section of a Leaf

[pic]

• Mesophyll

o Mesophyll is the entire tissue between the upper and lower epidermis is

Mesophyll is differentiated in two regions;

▪ Palisade parenchyma and

▪ Spongy parenchyma

• This differentiation gives two anatomical designations of the leaf

• Dorsiventral leaf

• Mesophyll is differentiated into palisade parenchyma (or palisade

mesophyll) on the adaxial (upper) side and spongy parenchyma (or

spongy mesophyll) on the abaxial (lower) side

• Common in dicot leaves

• Isobilateral leaf

• Leaf mesophyll is not differentiated this way (i.e., made of only

spongy or palisade parenchyma)

• Common in monocots

o Palisade Parenchyma (Palisade Mesophyll)

▪ Palisade parenchyma lies beneath the adaxial

epidermis

▪ Palisade mesophyll may be present below both surfaces or

occur only below the upper epidermis

▪ Consists of vertically elongated cylindrical cells in one

or more layers

▪ Cells are compactly arranged with the chloroplasts close to

the walls of the cell

▪ Main function is photosynthesis

o Spongy Mesophyll

▪ Lies below the palisade mesophyll, with irregularly shaped,

loosely arranged cells

▪ Contain fewer chloroplasts than palisade mesophyll

▪ Spongy cells facilitate exchange of gases with the help of

air spaces

▪ The pores or stomata of the epidermis open into sub

stomatal chambers, connecting to air spaces between the

spongy layer cells

o Vascular Tissues

▪ Veins are the vascular tissue of the leaf located in the

spongy layer of the mesophyll

▪ Based on pattern of venation, the vascular system of leaves

falls into two main classes:

• The reticulate (or net) venation typical of dicotyledons

• The parallel venation of the monocotyledons

▪ The veins are made up of xylem and phloem tissues

▪ The xylem typically lies over the phloem

▪ In dicotyledonous leaves the main veins are open and

usually collateral (less commonly bicollateral), closed in

monocot leaves

Figure 7.1: Transverse Section of a Leaf

[pic]

STEP 4: Pharmacognostic Importance of Epidermis (25 minutes)

• Leaves offer diagnostic characteristics which serve in quality control of

leaf drugs

o Shape, size and wall structure of the epidermal cells

▪ Straight –walled epidermal cells are found in medicinal plants such

as coca and Senna leaves

▪ Wavy-walled epidermal cells are in found in Datura stramonium,

Hyoscyamus niger and Atropa belladonna.

▪ Form, distribution and relation to epidermal cells of the stomata

▪ Stomata are classified on the basis of subsidiary cells into;

• Anomocytic Stomata

o When cells surrounding the stomata resemble other epidermal

cells

• Anisocytic stomata

o Stoma is surrounded by three or four subsidiary cells one of

which is markedly smaller than others

• Paracytic stomata

o Two subsidiary cells with their long axes parallel to the

pore

• Diacytic stomata

o Two subsidiary cells with their long axis at right angle to

the pore of the stomata

o Variations among anisocytic, paracytic and diacytic types

of stomata:

• Actinocytic type

o Subsidiary cells are arranged along the radii of a

circle. Form, distribution and abundance of epidermal

trichomes

• Trichomes offer physical and chemical protection from microbes, aphids

and insects.

o Types of trichomes are characteristic of a plant family or genus

▪ Clothing trichomes –cover surface of the leaf

▪ Glandular trichomes –may be unicellular or multicellular (they

store ergastic/drug substances)

• Multicellular trichomes may be;

o Uniseriate, biseriate, multiseriate or complicated branched structures

STEP 5: Classification of Leaves (25 minutes)

• External leaf characteristics (such as shape, margin, hairs, etc.) are

important for identifying plant species

• Leaves are determinant in growth i.e. they grow and achieve a specific

pattern and shape, then stop

• Other plant parts like stems or roots are non-determinant

• Leaves are classified on the basis of:

o Arrangement on the stem

o Alternate, opposite, whorled, rosulate,

o Divisions of the lamina

▪ Simple leaves, compound leaves (palmately compound leaves, pinnately

compound leaves, binately compound leaves)

o Leaf margin

▪ Entire, ciliate, crenate, dentate, denticulate, doubly toothed,

lobate, serrate, serrulate, lanceolate)

o Leaf Apex

▪ Acuminate, acute, cuspidate, ermaginate, obtuse, obcordate,

mucronate,

o Leaf base

▪ Acuminte, acute, cordate, cuneate,

o Surface of the leaf

▪ Farinose, glabrouse, verucose, viscid, pubescent, hirsute,

glandular)

STEP 6: Key Points (5 minutes)

• A leaf is a plant organ above the ground specialized for photosynthesis

• The leaf is made up of dermal, ground and vascular tissue systems

• The dermal tissue system consists of lower and upper epidermis

• The ground tissue system is found between the epidermal layers of leaf

STEP 7: Evaluation (5 minutes)

• What are the functions of the leaf?

• What are the external features of a leaf?

• What is the importance of the leaf in pharmacognosy?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 8: Morphology of the Flower

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define the flower

• List parts of flowers

• Classify flowers

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Introduction to Flowers (20 minutes)

|Activity: Buzzing (5 minutes) |

| |

|ASK students to pair up and buzz on the following question for 2 |

|minutes |

| |

|What is a flower? |

| |

|ALLOW few pairs to respond and let other pairs to add on points not|

|mentioned |

| |

|WRITE their response on the flip chart/board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Flower is the plant organ for sexual reproduction

• The flower produces gametes (sex cells)

• Flowers are produced on the stem of the plant

• Floral parts in monocotyledonous plants are divided into three or

multiple of three

• Floral parts in dicotyledonous plants occur in four or five

• Flowers may be unisexual or bisexual

o Dioecious plants

▪ Are plants with unisexual flowers appearing on different

plants

o Monoecious plants

▪ Unisexual male and female flowers appear on the same

plant

o Polygamous plants

▪ Plants that bear unisexual and hermaphrodite flowers on the

same plant

• Functions of the flower to the plant include;

o Flowers help in pollination process by insects, wind, birds, mammals

or by water

▪ Flowers pollinated by insects have bright colours, sweet

fragrance and produce nectar

▪ Flowers pollinated by wind have large stigmas, no or little

fragrance, and non- sticky pollens

▪ Flowers pollinated by birds are log tube shaped, have bright red

or yellow colours, and with no fragrance

▪ Flowers pollinated by mammals have white flowers with strong

fruity smell and open at night

▪ Flowers pollinated by water may have pollens which floats on

water

STEP 3: Structure of the Flower (40 minutes)

• A typical flower is made up of the following parts;

o Peduncle –the flower stalk

o Receptacle –bears the floral organs

▪ Forms the hypanthium if elongated below the calyx

▪ If below the ovary it is the gynophore or stalk of the ovary

o Calyx –made up of sepals (to protect young flower bud)

▪ Polysepalous if sepals are separate

▪ Gamosepalous if sepals are fused

o Corolla –made up of petals (often colourful)

▪ Polypetalous if petals are separate

▪ Gamopetalous if petals are fused

o Perianth –formed from sepals and petals together

o Stamen –male reproductive structures of the flower

▪ Made up of anther and filaments (produce pollen grains)

▪ Monadelphous if stamens are fused

▪ Diadelphous if stamens are separate

o Pollen -Grains containing the male gametes

o Pistil –female part of the flower

▪ Made up of stigma, style and ovary

o Carpel –A unit of compound pistil or ovary

o Ovule –bears the female gametes, located in the ovaries

o Gynoecium –one or more pistils (carpel, ovary, ovules, female gametes)

o Androecium –one or two whorls of stamens (filament, anther, pollen

grains, male gametes)

STEP 4: Classification of Flowers (45 minutes)

• Flowers are classified in various groups based on different criteria

o Based on presence of male, or female or both reproductive structures

▪ Perfect/Bisexual/Hermaphrodite Flower

• These flowers bear both male and female reproductive

structures

▪ Imperfect/Unisexual Flower

• Bears male or female reproductive structures

• Staminate flower (male flower)

• Pistillate/carpellate flower (female flower)

o Based on presence or absence of any structure

▪ Complete Flower

• Flowers bear sepals, petals, pistils, and stamens

▪ Incomplete Flowers

• Sepals, petals, pistils, or stamen is missing

o Based on the number of flowers

▪ Simple flowers

• One flower on an axis (receptacle)

o Compound flowers or Inflorescence

• Have more than one flower on the receptacle or axis

• The axis forms the rachis and florets are attached on pedicels

o Inflorescence are subsequently classified based on pattern of

arrangement into;

• Single inflorescence –same pattern of arrangement of florets

• Compound inflorescence –complex pattern

• Main inflorescences include;

o Raceme (or racemose)

o Spadix

o Spike

o Corymb

o Umbel

o Head

o Based on flora variations

▪ Flowers are grouped according to the placement of floral parts

on the receptacle into;

• Hypogynous flowers

o Sepals, petals, and stamens are attached to a convex or

conical receptacle at the base of the ovary

o The ovary is called superior and the perianth

is inferior or hypogynous

• Perigynous flowers

o Sepals, petals, and sometimes stamens borne on the edge or

margin of the receptacle and appear to form a cup around

the pistil

• Epigynous flowers

o Sepals, petals, and stamens appear to arise from the top

of the ovary

o The ovary is inferior and the perianth is superior or

epigynous

o Based on floral symmetry

▪ Regular or Actinomorphic flowers

• Flowers divisible into symmetrical halves by more than one

longitudinal plane through the axis

▪ Irregular or Zygomorphic flowers

• Flowers divisible only by a single plane into two mirror-image

halves

▪ Asymmetrical flowers

• Flowers indivisible into identical or mirror-image halves on

any plane

STEP 5: Key Points (5 minutes)

• Flower is the plant organ for sexual reproduction

• Flower produces gametes (sex cells) which are necessary for fertilization

to occur

• Hermaphrodite flowers bear both male and female reproductive structures

STEP 6: Evaluation (5 minutes)

• Mention parts of the flower?

• What is an epigynous flower?

• What is a staminate flower?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 9: Morphology of the Fruit

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define a fruit

• List parts of a fruit

• Classify fruits

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Introduction to Fruits (25 minutes)

|Activity: Buzzing (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What is a fruit? |

| |

|ALLOW few students to respond? |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARISE by using the content below |

• Fruit is the ripened ovary or ovaries of a seed-bearing plant

• Fruits may contain one or more seeds

• A fruit develops from one or more carpels

• After fertilization in the flowering stage, the ovary and sometimes

accessory parts develop into the fruit

• In some species, fruits may be formed without fertilization i.e.

parthenocapy

• Accessory parts including sepals, petals, stamens, receptacle, pedicel,

peduncle and inflorescence axis may be incorporated and become part of

the fruit for instance in apples and pineapple

STEP 3: Structure of the Fruit (30 minutes)

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What are the parts of the fruit? |

| |

|ALLOW few students to respond? |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Fruits consist of dermal, ground (fundamental), and vascular tissue

systems

• The fruit wall is made up three layers collectively forming the

pericarp;

o Exocarp

▪ The outermost layer

o Mesocarp

▪ The middle layer

o Endocarp

▪ The inner layer

• The fruits may also contain one or more seeds

STEP 4: Classification of Fruits (45 minutes)

• Fruits that are formed without including the accessory structures are

called true fruits e.g. tomatoes while those including accessory

structures are false fruits e.g. pears.

• Fruits may be classified based on the number of ovaries, number of

flowers and other structures forming the fruit, into;

o Simple fruits

▪ Fruits formed from one ovary in one flower

o Aggregate fruits

▪ Fruits formed from more than one ovary of one flower

o Multiple fruits

▪ Fruits formed from an inflorescence and include accessory

structures

• After maturity, fruits are also classified into fleshy/Succulent or

dry fruits

o Fleshy/Succulent fruits may be soft or hard

▪ Simple succulent fruits

• Have soft and fleshy epicarp and formed from single ovary

• They include;

o Berries

▪ Have soft epicarp and fleshy mesocarp and endocarp

o Hesperidiums

▪ Berries with a thicker skin containing oils

o Pepos

▪ Berries with a comparatively thick exocarp or rind

o Drupes/stones

▪ Have edible exocarp and fleshy mesocarp and inedible, hard

stone-like endocarp

o Pome

▪ A fleshy fruit with mature ovary and accessory structures

e.g. petals, sepals and receptacle

o Polydrupes

▪ Are soft aggregate fruits (fusion of several drupes) e.g.

strawberries, blackberries etc.

o Dry fruits may be dehiscent or indehiscent depending on whether

they split open to release the seeds or not. They include;

▪ Simple dry indehiscent fruits

• Samara

o A winged fruit

• Achene

o A hard dry fruit with one seed which almost feels the

pericarp but attached loosely

• Nuts

o Simple dry fruit similar to achenes, but formed from two

or three carpels. Pericarp is relatively hard and heavy

• Caryopsis

o It is a simple, dry fruit in which the testa and

pericarp are fused

▪ Simple dry dehiscent fruits

• Legumes

o Are dry fruits which split along both dorsal and ventral

sutures to release their seeds e.g. Cassia angustifolia

• Follicles

o Dry fruits which splits along inner suture only e.g.

strophanthus

• Capsules

o Dry fruits formed from two or more carpels

▪ Valvate Capsule –the tip split open

▪ Porose capsule –form pores to release seeds

▪ Loculicidal capsules –splits along locules

▪ Circumscissile capsules –split through the centre

of the fruit

▪ Septicidal capsule –split along the septa

STEP 7: Key Points (5 minutes)

• Fruit is the ripened ovary or ovaries of a seed-bearing plant containing

one or more seeds

• Fruits that are formed without including the accessory structures are

called true fruits

• A fruit is composed of the fruit wall and seeds

• The fruit wall is made up three layers, exocarp, mesocarp and endocarp

which collectively form the pericarp

• Fruits are classified based on the number of ovaries, number of flowers

and other structures forming the fruit

• After maturity, fruits are also classified into fleshy or succulent

fruits and dry fruits

STEP 8: Evaluation (5 minutes)

• What is a fruit?

• What are dry fruits?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 10: Morphology of the Seed

Total Session Time: 60 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define a seed

• Describe the structure of a seed

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Definition of a Seed (10 minutes)

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What is a seed? |

| |

|ALLOW few students to respond? |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Seed is the structure formed by plants from a ripened ovule after

fertilization

• There numerous sizes and shapes of seeds

• Seeds are formed within a fruits of gymnosperm and angiosperms

• Seeds may be formed from orthotropous ovules, campylotropous or

anatropous ovules

STEP 3: Structure of a Seed (35 minutes)

|Activity: Small Group Discussion (10 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

|Write down the external structures found on a seed |

| |

|ALLOW students to discuss for 15 minutes |

| |

|ALLOW few groups to present and the rest to add points not |

|mentioned |

| |

|CLARIFY and SUMMARIZE by using the contents below |

• Basic parts of a seed are the embryo, endosperm and the seed coat

External structures of a seed

o Seed coat

▪ Most seeds have two seed coats

▪ Testa (the outer seed coat)

• Outer most protective layer of the seed –form the seed coat

• Protects the seed

• Thickness varies with type of seed

▪ Tegmen

• The inner seed coat

o Funicle or stalk

▪ A structure that attaches the seed to the placenta

o Micropyle

▪ An opening that marks position of the radicle

o Hilum

▪ Scar left by the funiculus (attachment to the embryo)

o Raphe

▪ Fibrovascular tissue formed by adhesion of funicle and testa

o Aril

▪ Expansion of placenta or funicle over the surface of the seed

▪ Formed in some seeds

o Elaiosome

▪ Fleshy structures rich in lipids and proteins attached to the

seed

o Caruncle or Strophiole

▪ A structure that arises from the testa near the hilum

• Internal structures of a seed

o Embryo

▪ The immature plant within the seed from which a new plant grows

• Made up of cotyledons

o One cotyledon in monocotyledons plants

o Two cotyledons in almost all dicotyledons and two or more

in gymnosperms

• Has radicle and plumule

▪ Endosperm

• A tissue that forms beginning of food storage of a plant

• Consists of two parts, one part stores starch and the other

part stores proteins

• Exalbuminous seeds

o Seeds with no endosperm at maturity e.g. sunflower

• Albuminous seeds

o Have endosperm at maturity e.g. castor seed

STEP 5: Key Points (5 minutes)

• Seed is the structure formed by plants from a ripened ovule after

fertilization and occurs in many shapes and sizes

• Seeds may be formed from orthotropous ovules, campylotropous or

anatropous ovules

• The seed consists of a seed coat which covers the seed and made up of the

testa and tegmen

• The internal of a seed consists of the embryo and endosperm

• In some seeds the endosperm is absorbed and absent at maturity forming

exalbuminous seeds while in albuminous seeds the endoperm persists

STEP 6: Evaluation (5 minutes)

• What is a micropyle?

• What are the functions of a seed coat?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 11: Pharmaceutical Barks

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define a bark

• Explain the structure of a bark

• Explain the curvatures of a bark

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• Computer and LCD Projector

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Introduction to Pharmaceutical Barks (10 minutes)

|Activity: Buzzing (5 minutes) |

| |

|ASK students to pair up and buzz on the following question for 2 |

|minutes |

| |

|What is a bark? |

| |

|ALLOW few pairs to respond and let other pairs to add on points not |

|mentioned |

| |

|WRITE their response on the flip chart/board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• The bark is the outer surface of the stem and is made of tissues produced

by the cambium. The bark lies outside the cambium.

STEP 2: Structure of Pharmaceutical Barks (20 minutes)

|Activity: Small Group Discussion (15 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

| |

|Describe the structure of a bark |

| |

|ALLOW students to discuss for 15 minutes |

| |

|ALLOW few groups to present and the rest to add points not mentioned|

| |

|CLARIFY and SUMMARIZE by using the contents below |

• A young bark is composed of the following tissues;

o Epidermis

▪ A layer of closely fitting cuticularized cells with occasional

stomata

o Primary cortex

▪ A zone usually consisting of chlorophyll-containing collenchyma

and parenchyma

o Endodermis

▪ Inner layer of cortex, frequently containing starch

o Pericycle

▪ May be composed of parenchyma or fibres, groups of fibres often

occur opposite each group of phloem

o Phloem: Consisting of sieve tubes, companion cells and phloem

parenchyma separated by radially arranged medullary rays

o Activity of the cambium and cork cambium or phelogen modifies the

structure of the young bark

o Pericycle is ruptured

o Phelogen produces secondary cortex or phelloderm

o Periderm is formed

o Lenticels replace stomata for gaseous exchange

o The fully matured barks have two parts; the outer bark and the inner

bark

o But in presentation for the market in some drugs only the inner bark

is presented e.g. in cinnamon

o The bark shows certain characteristics that are of diagnostic

importance;

▪ Origin of the bark

▪ Size and shape of the bark

▪ Fracture of the bark

STEP 4: Bark Curvatures (15 minutes)

• Natural curvature of the bark increases when the bark is removed from the

tree and dried

• Large pieces of trunk bark, especially if subjected to pressure may be

nearly flat

• Commercial bark is presented for the market in various curvatures;

o Flat

o Curve

o Channelled

o Single quill

o Double quill

o Compound quill

STEP 6: Key Points (5 minutes)

• The barks consist of all tissues outside the cambium

• The bark is divided into inner bark and outer bark

• A young bark differs from bark produced after secondary growth

STEP 7: Evaluation (5 minutes)

• What is a bark?

• Mention curvatures of barks?

• What are the structures present in a bark?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 12: Cultivation of medicinal plants

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Classify medicinal plants

• Explain the cultivation of medicinal plants

• List factors affecting cultivation of medicinal plants

• Explain the importance of plant as a major source of drugs

• List available plants commonly used as source of drugs in Tanzania

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and laptop

SESSION OVERVIEW

|4 | | |Factors Affecting Cultivation of |

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Classification and Nomenclature of Medicinal Plants (20 minutes)

• Classification of medicinal plants

o Alphabetical Classification

▪ This classification employs the use of either Latin or Vernacular

names of the medicinal plant

▪ This method is simple and suitable for quick reference

▪ Disadvantageously, this method does not give indication of

interrelationships between drugs e.g. in Pharmacopoeias

o Taxonomic Classification

▪ This method is based on botanical classification

▪ Drugs are arranged according to the plants from which they

are obtained

▪ Drugs are grouped into families, Classes, orders, genera and

species

o Morphological Classification

▪ Physical features of the drugs are used in the

classification

• Organized drugs

o For instance, leaves, flowers, fruits, seeds, wood, barks,

rhizomes & roots

• Unorganized drugs

o For instance, dried lattices, extracts, gums, resins, oils, fats and

waxes

o Pharmacological or therapeutic Classification

▪ Drugs are classified according to pharmacological actions of their

most important constituents or their therapeutic uses, e.g.

cardiotonic drugs, CNS stimulants, Muscle relaxants, etc.

o Chemical or Biogenetic Classification

▪ Drugs are classified according to their important constituents

e.g. alkaloids, glycosides, volatile oils

▪ They are also classified based on their biosynthetic pathways

• Nomenclature in Medicinal Plants

o The binomial system founded by the Swedish biologist Linnaeus is used

o The first name (genus name) starts with a capital letter and the

second name (species) begins with a small letter

o Genus and species names may be followed by author’s name who first

described the species or variety. e.g. Artemisia cina Berg.,

Caryophyllos aromaticus L

o Sometimes, species name is derived from author’s name, e.g. Cinchona

Ledgeriana after Charles Ledger

o The species name usually indicates certain characteristics of the

plant e.g.

▪ Cassia acutifolia means “sharp pointed leaflets”

▪ Atropa belladonna (bella= beautiful, donna=lady)

▪ Piper nigrum (black)

▪ Myristica fragrans (nice aroma)

▪ Hydrastis Canadensis (growing in Canada)

▪ Papaver sominferum (inducing sleep)

o The generic name may indicate certain characters of the plant e.g.

▪ Glycyrrhiza means gluco = sweet, riza = root,

STEP 3: Cultivation of Medicinal Plants (30 minutes)

• Drugs may be collected from wild or cultivated plants

• Collection may be done by skilled or unskilled labour

• Collection from cultivated sources ensure sustainability of medicinal

plants

• In some cases, pharmacopoeias specify cultivated species such as Fennel,

ginger, cinnamon and opium

• Disadvantages of Wild Plant Collection

o Sparse distribution e.g. Sceletium tortuosum. Potentially difficult to

transport plant to area of processing

o Difficult access (e.g. forests, mountains etch)

o Collector ignorance leads to admixture of other plants, collection of

undesired plant parts or stage of development or during an incorrect

season ( loss of medicinal activity.

o Damage to natural environment which leads to extinction of a species.

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What are the advantages of cultivation of medicinal plants? |

| |

|ALLOW few students to respond? |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARISE by using the content below |

• Advantages of Cultivated Medicinal Plants

o Only desired species are collected therefore uniform quality.

o Collection, transport and access to processing facilities is improved.

o Better control of soil quality, pests and plant disease.

o Supply: Constant and Regular (Controlled)

o Collectors are trained

STEP 4: Factors Affecting Cultivation of Medicinal Plants (25 minutes)

• Environmental (Exogenous) Factors

o Temperature

▪ It is a major factor that affects both the growth/development and

metabolism of the plants

▪ Each plant is specialized to adapt to its native environment

▪ But most plants are able to exist in wide temperature ranges e.g.

Tropical and Sub-tropical plants in temperate regions

▪ Temperature affects plant chemical reaction rates

• e.g. Datura stramonium produces lower alkaloids in cloudy/rainy

weather (winter)

• Volatile oils are produced more readily in warmer weather

o Very hot days lead to a physical loss of oil

• Growing peppermint in shade rather than the sun.

o Rainfall

▪ Annual rainfall, distribution, humidity effect medicinal

plants

▪ Rainfall influences the production of glandular hairs

▪ Continuous rainfall may lead to loss of water-soluble

substances such as glycosides, tannins, flavonoids and some

volatile oils through leaves and roots

o Day-length (sunlight)

▪ Amount and intensity of light needed differs from plant to

plant

▪ Amount of glycosides, alkaloids and volatile oils produced

are greatly affected by amount of sunlight

• Long day: menthone, menthol and menthofuran traces

• Short day: menthofuran is a main component

▪ Belladonna, Stramonium and Cinchona ledgeriana full sunshine

gives high content of alkaloids than does shade

▪ Other species: produce more active constituents at night

e.g. Nicotiana

o Radiation

▪ Type of radiation plants receive e.g. Ocimum basilicum –

plants grown in glass houses have less phenols and terpenoids

in the leaves (flavonoids, volatile oils)

o Latitude and Altitude

▪ Gentian produce bitter constituents when grown in higher

altitude

▪ Thyme and Peppermint produce less constituents when grown in

higher altitude

▪ Coconut needs a maritime climate

▪ Sugar cane is lowland plant

▪ Tragacanth, Cinchona succirubra require elevation

▪ Tea requires (1000-2000 M), coffee (800 – 1800 M), and cocoa

(100 – 200 M)

▪ Peanut & olive grown in the subtropics produce a higher

unsaturated fat content.

o Soil Condition

▪ Soil character, composition, permeability, porosity all

effect growth of medicinal plants e.g.

• Chalky soil lead to poor of Digitalis

• Crop rotation improves nutrient content of soils

• pH of soil affects inorganic compounds of soil

• Genetic (Endogenous) Factors

o Allelopathy

▪ Allelopathy is the constant effect which living organisms exert on

each other, which may be either beneficial or harmful

▪ Different plants growing together affect each other in terms

of:

• Germination rate

• Leaf development

• Fruit maturation

• Chemical constituents produced

▪ It is transmitted between plants in a number of ways

• Exhalation of leaves

• Root secretions

• Extractions from fallen leaves into the soil

o Mutual dependant organisms (beneficial) symbiosis e.g. Urtica

dioica

o Destructive allelopathy antibiosis e.g. Belladonna growth is

inhibited when cultivated next to mustard

• Post-Cultivation Factors

o Drying & storage methods of drugs

STEP 5: Plant Breeding Methods (20 minutes)

• Plant breeding methods;

o Selection

o Hybridization

o Transgenic medicinal plants

• Selective Breeding

o Individual plants showing the most desirable characteristics are chosen

and interbred

o Second population has improved quality

• Advantages of Selective Breeding

o Improved growth rate, ]

o Disease resistance

o Winter hardiness

o Increased yield of medicinal actives

• Hybridisation

o Mating of different species or varieties to produce a hybrid progeny,

different from both parents (incorporating desired characteristics).

E.g. Mentha piperita and M. spicata are naturally occurring hybrids

• Transgenic Medicinal Plants

o Genetic Engineering: Recombinant DNA

▪ Transfer DNA sequences from the chromosomes of 1 plant to

another

▪ Lead to the artificial transfer of a particular character

from one organism to another

• Plant Propagation

o Seed

▪ In digitalis for instance, treatment of seed prior to sowing may

influence germination, higher plants need soaking before germination

(water/acid)

o Vegetatively

▪ Includes bulb, tuber, rhizome

o By division

▪ plant separated from aerial stems/buds, each with roots and growing

point

o Runners

▪ mint

o Stolons

▪ Liquorice

o Cuttings

▪ Pieces of stem are used

o Grafting

o Fermentation

o Inoculation

o Cell culture

STEP 6 Key Points (5 minutes)

• Correct cultivation and harvesting is aimed at producing high quality

medicinal plants

• General plant breeding methods include selection, hybridization and

transgenic medicinal plants

• Cultivation of medicinal plants is affected by environmental, genetic and

post-collection factors

STEP 7: Evaluation (5 minutes)

• What are the factors affecting cultivation of medicinal plants?

• What are the advantages of cultivation of medicinal plants?

• What are the factors of variation of active ingredients?

STEP 8: Assignment (10 minutes)

|Activity: Take home Assignment (10 minutes) |

| |

|DIVIDE students in groups or individual. |

| |

|ASK the students to work on the following assignment |

| |

|Explain the importance of plant as a major source of drugs |

|ALLOCATE time for students to do the assignment and submit |

| |

|REFER students to recommended references |

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 13: Collection, Processing and Storage of Medicinal Plants

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• List methods for collection of medicinal drugs

• Explain the importance of processing medicinal plants

• Explain methods of drying of crude drugs

• Explain storage of medicinal plants

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• Computer and LCD Projector

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Collection of Medicinal Plants (30 minutes)

• Collection refers to harvesting or obtaining drugs from medicinal plants

• Drugs may be collected from wild or cultivated plants

• Collection may be done by skilled or unskilled labour

• Collection from cultivated plants is more advantageous and ensures

sustainability of medicinal plants

• In some cases, pharmacopoeias specify collection of certain drugs from

cultivated species such as Fennel, ginger, cinnamon and opium

• Some drugs e.g. senna, tragacanth and others may be collected from wild

or cultivated species.

• Active constituents in plants vary in amount and nature throughout the

year, so collection should be done at the right time when active

constituents are at the highest levels. For instance,

o Time (season) of the year

▪ Rhubarb contains high levels of anthranols in winter and high

levels of anthraquinones in summer. Anthranol are oxidized to

anthraquinones in summer

o Time of the day

▪ Digitalis is collected in the afternoon contains more cardiac

glycosides

▪ Solanaceous leaves collected in the morning have more

alkaloids

o Stage of maturity

▪ In Eugenia caryophyllus, buds contain high oil but mother “blown”

cloves contain very little oil

▪ Vanilla has highest levels of vanillin 8 months after flowers

open

• General factors to consider when harvesting/collecting drugs from

medicinal plants;

o Underground organs are collected when aerial parts die down

o Leaves are collected when flowers are beginning to open

o Flowers are collected in dry weather and just before they fully

expand e.g. cloves

o Fruits and seeds are collected when fully mature but unripe

o Barks are collected in damp weather

o Unorganized drugs are collected in dry weather

o Leaves, flowers and fruits should not be collected when covered with

dew or rain

o Discoloured or parts attacked by insects should not be collected

o Large organs should be sliced soon after collection to facilitate

drying

o Limits of unwanted parts in desired parts must be considered when

collecting medicinal plants e.g. aerial stems in rhizomes

STEP 3: Processing of Crude Drugs (45 minutes)

• After collection, drugs should be processed to meet various requirements

such as market requirements

• Processing of crude drugs is important in order prevent deterioration

• Processing of drugs from natural sources depends on morphological nature,

constituents, geographical source and other related factors

• Drying is an important aspect of processing crude drugs

o There various reasons for drying drugs obtained from medicinal

plants

▪ To decrease size and weight i.e. to facilitate packing,

transport and storage

▪ To facilitate powdering

▪ To prevent enzyme action

▪ To prevent microbial growth

▪ To prevent degradation of active constituents

o Enzyme action may be desired or undesirable after collection

▪ When enzyme action is desired after collection e.g. in vanilla

pods, gentian roots and cocoa seeds, the collected drug is dried

slowly at moderate temperature

▪ Drying is done as soon as possible after harvesting when enzyme

reaction is not desired e.g. digitalis leaves

o Methods of Drying

o There are various methods that are used in drying crude drugs

o The choice of a drying method depends on physical characteristics of

the plant and chemical characteristics of the active constituents

▪ Air Drying

• Sun Drying

o Is done when drugs are not adversely affected by excessive

sunlight.

o Drugs are dried in thin layers and tuned over occasionally

o Drugs dried in this way include clove and cardamom

• Shade Drying

o Done when sunlight causes discoloration and warping/shrivelling

of the drugs e.g. cinnamon

▪ Artificial Drying

• Artificial source of heat is used in the drying process

• Drying in the oven (oven drying) is the commonest methods used in

artificial drying

• Artificial drying is more accepted and more rapid than air-drying

• Artificial drying is more suitable for use in the wet weather

• Drying temperature is governed by constituents

o Generally, leaves, herbs and flowers are dried between 20-40oC,

barks and roots: 40-65oC

• When done rapidly, the drugs retain colour and aroma

▪ Vacuum Drying

• It is also done in oven, but at low temperature

• Low pressure ensures rapid and complete drying

• It is an expensive method and thus reserved for expensive drugs or

drugs which cannot be sufficiently dried by other methods

▪ Lyophilisation

• Involves freezing of the drug and then evaporation under low

pressure

• Very suitable method for drugs that are very sensitive to heat

• The resulting product is a fine powder

• This method is used for drying biological fluids, enzymes,

proteins and royal jelly

• Some general conditions and techniques when drying medicinal plants:

o For Leaves/Herbs:

▪ Temperature should be between 40-50º C to maintain good colour

▪ Leaves or herbs should normally be destalked first

▪ They are best dried for short periods of time only to prevent

shrivelling and discoloration

▪ They may be bleached through the drying process

o For Roots/Rhizomes:

▪ They should be washed

▪ They should be sliced

▪ They should be dried between at temperatures between 30-65ºC

▪ Too high temperature may prevent further drying in deeper parts

of the drug

▪ Thick organs may require long periods of drying (10days-3weeks)

to avoid mould growth

o For Flowers;

▪ Flowers are normally destalked before drying

▪ Flowers may also be bleached when dried

o Volatile oil-containing drugs;

▪ Are air-dried at very low temperature to avoid volatilization of

oil contents

▪ They should be dried separately from other herbs

o Fruits and Seeds;

▪ They are normally partially dry before harvesting

▪ They may be air-dried afterwards

▪ Seeds are normally separated from the fruits before drying

▪ Fruits are normally left whole

▪ Some fruits (cardamom) rupture due to excessive heat.

o Bark

▪ Occasionally requires the removal of the outer layers

o Factors to consider when making a choice of a drying technique

▪ Physical characteristics of the plant

▪ Chemical characteristics of the plant

• Volatile Oils: (Thyme) Dried separately, at low temperature

• Starchy herbs (oats): gelatinize if overheated

▪ Changes occurring in herbs when drying

▪ Changes due to enzyme action

▪ Oxidation

▪ Volatilisation

▪ Browning

STEP 4: Storage of Crude Drugs (30 minutes)

|Activity: Small Group Discussion (10 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

|How should crude drugs be stored? |

| |

|ALLOW students to discuss for 15 minutes |

| |

|ALLOW few groups to present and the rest to add points not |

|mentioned |

| |

|CLARIFY and SUMMARIZE by using the contents below |

• During storage, drugs are affected by physicochemical and biological

factors

• Physicochemical factors include light, moisture, temperature and air

oxygen while biological factors include fungi, bacteria, worms, insects

and mites

• Long storage is not recommended, due to deterioration except in cascara

bark. Active constituents decrease massively

• Drugs should be stored in sealed containers in cool dark places

• Generally, the permissible moisture content is 8% or below.

• Air dried drugs are always liable and are easily attacked by insects and

other pests, so they should be frequently examined during storage or may

require sterilization by ethylene oxide or methyl chloride before storage

STEP 5: Key Points (5 minutes)

• Drugs may be collected from wild or cultivated plants

• Collection of drugs may be done by skilled or unskilled labour

• Collection from cultivated sources ensure sustainability of medicinal

plants

• Drying is an important process in the preparation of drugs for market

STEP 6: Evaluation (5 minutes)

• What are the factors to consider when harvesting medicinal plants?

• What are the reasons for drying crude drugs?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 14: Extraction of Active Medicinal Principles from Natural Sources

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Definition of terms

• List types of extracts

• Explain factors affecting extraction process

• Explain Mechanism of solvent extraction

• Outline properties and types solvents

• Explain methods for extraction of active drugs

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD Projector and laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Objectives (05 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Definition of terms (10 Minutes)

• Extraction is the method of removing active constituents from a solid or

liquid by means of liquid solvent.

o The separation of medicinally active portions of plant or animal

tissues from the inactive or inert components by using selective

solvents.

o In this method the wanted components are dissolved by the use of

selective solvents known as menstrum & undissolved part is a marc,

after the extraction unwanted matter is removed.

• Extract: Extracts can be defined as preparations of crude drugs which

contain all the constituents which are soluble in the solvent.

• Marc: Solid residue obtain after extraction Menstruum

• Solvent is a liquid substance capable to dissolve other substances

(solutes) without chemical changes.

o (The term “Solvents” refers to a class of chemical compounds described

by function – the term derives from Latin, meaning roughly to “loosen.”

In chemistry, solvents – which are generally in liquid form – are used

to dissolve, suspend or extract other materials, usually without

chemically changing either the solvents or the other materials

Step 3: Types of Extracts (05 minutes)

• Type of extracts

o Dry extract (Tab, cap.) E.g. belladonna extract

o Soft (Ointment, suppository) E.g. glycerrhiza extract.

o Liquid: As tincture.

STEP 4: Properties and Types of Solvents (30 minutes)

|Activity: Buzzing (10 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

| |

|What are types of solvents? |

| |

|ALLOW students to discuss for 15 minutes |

| |

|ALLOW few groups to present and the rest to add points not |

|mentioned |

| |

|CLARIFY and SUMMARIZE by using the contents below |

• Types of Solvent

o Molecular structure of solvents

o Inorganic solvents

o Organic solvents

• Molecular structure of solvents

o Molecular structure of solvents, Ability of a substance to dissolve

another substance is determined by compatibility of their molecular

structures (like dissolves like).

▪ Types of molecular structures of the solvents are as follows:

• Polar protic solvents

o A polar protic molecule consists of a polar group OH and a non-

polar tail. The structure may be represented by a formula R-OH.

Polar protic solvents dissolve other substances with polar protic

molecular structure. Polar protic solvents are miscible with water

(hydrophilic).

Examples of polar protic solvents:

▪ Water (H-OH),

▪ Acetic acid (CH3CO-OH)

▪ Methanol (CH3-OH),

▪ Ethanol (CH3CH2-OH),

▪ n-propanol (CH3CH2CH2-OH),

▪ n-butanol (CH3CH2CH2CH2-OH).

• Dipolar aprotic solvent

o Dipolar aprotic molecules possess a large bond dipole moment (a

measure of polarity of a molecule chemical bond). They do not

contain OH group.

Examples of dipolar aprotic solvents:\

▪ Acetone ((CH3)2C=O),

▪ Ehyl acetate (CH3CO2CH2CH3),

▪ Dimethyl sulfoxide ( (CH3)2SO ),

▪ Acetonitrile (CH3CN),

▪ Dimethylformamide ( (CH3)2NC(O)H ).

• Non-polar solvents

o Electric charge in the molecules of non-polar solvents is evenly

distributed, therefore the molecules have low dielectric

constant. Non-polar solvents are hydrophobic (immiscible with

water). Non-polar solvents are liphophilic as they dissolve non-

polar substances such as oils, fats, greases.

Examples of non-polar solvents:

▪ carbon tetrachloride (CCl4),

▪ benzene (C6H6),

▪ and diethyl ether ( CH3CH2OCH2CH3),

▪ hexane (CH3(CH2)4CH3),

▪ methylene chloride (CH2Cl2).

• Inorganic solvents

o The most popular inorganic (not containing carbon) solvents are

o water (H2O) and aqueous solutions containing special additives

(surfacants, detergents, PH buffers, inhibitors).

o Other inorganic solvents are liquid anhydrous

▪ Ammonia (NH3),

▪ concentrated sulfuric acid (H2SO4),

▪ sulfuryl chloride fluoride (SO2ClF).

• Organic solvents

o Oxygenated solvent is an organic solvent, molecules of which contain

oxygen. Oxygenated solvents are widely used in the paints, inks,

pharmaceuticals, fragrance sectors, adhesives, cosmetics, detergents,

food industries.

Examples of oxygenated solvents:

▪ Alcohols,

▪ Glycol ethers,

▪ Methyl acetate,

▪ Ethyl acetate,

▪ Ketones,

▪ Esters,

▪ Glycol ether/esters

STEP 5: Mechanism of Solvent Extraction (15 minutes)

• Mechanism of solvent extraction

o Dissolution of extractive substances out of disintegrated cells.

o Dissolution of extractive substances out of intact plant cell by

diffusion (requires steeping and swelling)

o Penetration of the solvent into the plant cells and swelling of the

cells.

o Diffusion of the dissolved extractive substances out of the cell.

o Plant constituents are usually contained inside the cells.

o Therefore, the solvent used for extraction must diffuse into the cell

to dissolve the desired compounds whereupon the solution must pass the

cell wall in the opposite direction and mix with the surrounding

liquid.

o An equilibrium is established between the solute inside the cells and

the solvent surrounding the fragmented plant tissues

STEP 6: Factors Affecting Extraction Process (05 Minutes)

• Nature of drug

• Solvent

• Temperature

• pH

• Particle size

STEP 7: Methods of extraction (45 minutes)

• Types of extractions are: Infusion, Decoction, Digestion, Maceration,

Percolation, Continues hot extraction, Supercritical fluid extraction,

counter current extraction, Microwave assisted extraction, Ultra

sonication-Assisted Extraction:

o Infusion

▪ Infusion: Fresh infusions are prepared by macerating the crude

drug for a short period of time with cold or boiling water. These

are dilute solutions of the readily soluble constituents of crude

drugs.

• Types of Infusion:

o Fresh Infusion: e.g. Infusion of orange (

o Concentrated Infusion: e.g. concentrated infusion of Quassia

o Decoction

▪ Decoction: In this process, the crude drug is boiled in a specified

volume of water for a defined time; it is then cooled and strained or

filtered. This procedure is suitable for extracting water-soluble,

heat stable constituents. e.g. Tea , Coffee

o Digestion

▪ This is a form of maceration in which gentle heat is used during

the process of extraction. It is used when moderately elevated

temperature is not objectionable. The solvent efficiency of the

menstruum is thereby increased. e.g. Extraction of Morphine

o Maceration

▪ Maceration: In this process solid ingredients are placed in a

stoppered container with the whole of the solvent and allowed to

stand for a period of at least 3 days (3 – 7 days) with frequent

agitation, until soluble matter is dissolved. The mixture is then

strained (through sieves / nets), the marc pressed and the combined

liquids clarified (cleaned by filtration) or by decantation, after

standing.

• Types of maceration

o Simple maceration: for organized and unorganized Crude drug e.g.

i) Tincture of Orange ii) Tincture of Lemon iii) Tincture of

Squill

o Double maceration: Concentrated infusion of orange

o Triple maceration: The maceration process may be carried out with

help of heat or stirring e.g. i) Concentrated infusion of Quassia

ii) Concentrated infusion of Senna

STEP 8: Key Points (5 minutes)

• Extraction is essential for isolation of different chemical constituent

from crude drug material.

• Depends on properties of material to be extracted.

• Hence it is necessary to study extraction methods in detail.

STEP 9: Evaluation (5 minutes)

• What are solvents used in extractions?

• What are the methods of extractions?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 15: Adulteration of Medicinal Plants

Total Session Time: 60 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define adulteration

• List methods of adulteration

• Explain the effects of adulteration

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and Laptop

SESSION OVERVIEW

|3 | 25 |Presentation |Methods and Effects of |

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Meaning of Adulteration (10 minutes)

• Adulteration is defined as anything causing debasement of a drug

• An adulterant is a medicinal plant which does not conform to official

standards or which does not comply with the requirement of the

pharmacopoeia cheap and easily available in large quantities

o An adulterant must be

• Adulteration or debasement of medicinal plants are of two major types;

o Deliberate adulteration

▪ This is intentional and normally commercial mainly for enhancement

of profits

o Accidental adulteration

• Deliberate adulteration is usually practised when certain medicinal

plants are scarce or expensive

• Adulteration of crude drugs usually involves practices such as

substitution of the original crude drugs partially or fully with other

substances which are either free from or inferior in therapeutic and

chemical properties

• Adulteration can occur through;

o Faulty collection of the drug

o Improper preparation of the drug

o Poor storage condition

o Deliberate practices

• Reasons for adulteration of crude drugs include;

o Scarcity of the drug

o High price of the drug in the market e.g. clove, cardamom

o Contraband drug e.g. opium

STEP 3: Methods and Effects of Adulteration (25 minutes)

• Inferior medicinal plant quality

o Which leads to a sub-standard drug

o This may result from;

▪ Ignorance/carelessness e.g. collection of genuine material

regardless of the time factor –collecting herbs prior/after ideal

time

▪ Collection at incorrect stage of development e.g. coriander – fully

ripe fruits (should be nearly ripe), clove (flowers in bud stage)

▪ Collection of parts which are not medicinally valuable e.g.

Chamomile leaves

▪ Collection of incorrect herb (close resemblance to intended herb)

▪ Imperfect preparation e.g. not removing undesired parts e.g. cork

from ginger rhizome/incorrect drying conditions

▪ Incorrect storage: e.g. volatile oils: cool, dry place in air

tight containers

▪ Inferiority may be avoided by careful selection of the plant

material

• Spoilage of Drug

o When the quality or medicinal value/ usefulness of herb is impaired or

destroyed by bacterial/ fungal action, insects, rodents or other pests

o Normally results from incorrect storage (effects of water/temperature)

o Avoided by careful attention to the drying and storage conditions

• Deterioration

o Occurs when value or quality of the drug has been impaired

• Admixture

o Admixture occurs when another species is added to the medicinally

valuable drug; intentional or accidentally

o This may result from;

▪ Poor collection due to unskilled labour

▪ Presence of plant parts other than those allowed by the

definition

▪ Collection of foreign material (stones, dirt)

• Sophistication with inferior varieties

o This is the deliberate addition of inferior material with the intention

of decreasing medicinal action of the desired drug e.g.

▪ Candle wax coloured yellow and being offered as Beeswax

▪ Addition of flour to powdered ginger with chillies for potency

• Substitution

o Substitution is the addition of an allied drug, or one which is

botanically different e.g. Digitalis thaspi for Digitalis purpurea

• Addition of worthless heavy materials

o Large mass of stomes mixed with liquorice root, pieces of limestone

are added in asafoedita

• Adulteration causes problems in natural drugs

STEP 4: Key Points (5 minutes)

• Adulteration addition of anything into the crude drugs that causes

debasement of that drug

• An adulterant is a medicinal plant which does not conform to official

standards or which does not comply with the requirement of the

pharmacopoeia.

• Deliberate adulteration is usually practiced when the drug in question is

scarce or expensive

STEP 5: Evaluation (5 minutes)

• What is adulteration of crude drugs?

• What is sophistication?

• What are effects of adulteration?

STEP 6: Take Home Assignment (10 minutes)

|Activity: Take Home Assignment (10 minutes) |

| |

|DIVIDE students in groups or individuals |

| |

|ASK the students to work on the following Assignment |

|List monographs of medicinal plants |

|List the effects of adulteration |

|List classes of plants containing toxic substances |

|List toxic substances from plants |

|List common misuses of medicinal plants |

| |

|ALLOCATE time for students to do the assignments and submit |

| |

|REFER students to recommended reference |

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 16: Introduction to Ergastic Substances

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define ergastic substances

• Classify ergastic substances

• Describe carbohydrates

• Describe proteins

• Gums, mucillages and Pectins

• Describe tannins

• Describe ergastic crystals

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Objectives (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Meaning and Classification of Ergastic Substances (10 minutes)

• Ergastic substances are non-living cell contents which can be identified

by microscopical examination or by chemical and physical tests

• Ergastic substances are food reserve (storage products) or by-products of

metabolism (excretory/secretory products)

• Classes of ergastic substances are;

o Carbohydrates

o Proteins

o Fixed oils and fats (Elaioplasts/spherosomes)

o Alkaloids (and purines)

o Glycosides

o Gums, mucilages and Pectins

o Volatile oils and Resins

o Tannins

o Crystals (Calcium oxalate, calcium carbonate and silica)

STEP 3: Carbohydrates (15 minutes)

|Activity: Buzzing (10 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

| |

|What are the characteristics and chemicals tests of cellulose and |

|starch? |

| |

|ALLOW students to discuss for 10 minutes |

| |

|ALLOW few groups to present and the rest to add points not mentioned|

| |

|CLARIFY and SUMMARIZE by using the contents below |

• Cellulose and starch are the main ergastic substances of plant cells

• Cellulose is the chief component of cell wall

• Starch occurs as a reserve material in the protoplasm

o Found in plastids (leucoplasts and amyloplasts)

o Occurs in granules (starch grains) of different sizes in almost all

organs of plants

o Occurs abundantly in roots, rhizomes, fruits and seeds

o Physical tests:

▪ Pure starch is a white, tasteless and odourless powder insoluble

in cold water or alcohol

o Chemical tests for starch granules

▪ Starch are unique in shape of starch granules in granular size,

shape and crystallization pattern

▪ Starch grains are observed under the microscope e.g. when stained

with iodine

STEP 4: Proteins (25 minutes)

|Activity: Small Group Discussion (10 minutes) |

| |

|DIVIDE students into small manageable groups |

|ASK students to discuss on the following question |

| |

|What are the characteristics and chemicals tests of proteins? |

| |

|ALLOW students to discuss for 10 minutes |

|ALLOW few groups to present and the rest to add points not |

|mentioned |

| |

|CLARIFY and SUMMARIZE by using the contents below |

• Proteins are large macromolecules made up of long chains of amino acids

joined by peptide bond

• Proteins are the main component of living protoplasm

• Proteins also occur as inactive ergastic bodies in amorphous or

crystalline forms

• They occur in form of aleurone grains which are well seen in oily seeds

(e.g. castor seeds)

• Simplest aleurone grain consists of a mass of proteins surrounded by a

thin membrane

• Ground mass of protein encloses one or more rounded bodies or globoids

and an angular body known as crystalloids

• So, microscopically, they are observed as mass of protein surrounded by

thin membrane (globoidal in shape)

• Aleurone grain are best seen after deflating and removal of starch (if

starch is present in large amounts)

• Chemical tests

o Millon’s reagent, which stains the protein red on warming

o Iodine solution, which stain the ground substance and crystalloid

yellowish-brown but leaves the globoids unstained

o Picric acid which stain stains the ground substance and crystalloid

yellow

STEP 5: Gums, Mucillages and Pectins (15 minutes)

• These are polysaccharides complexes formed from sugar and uronic acid

units

• They are insoluble in alcohol but dissolve or swell in water

• They are usually formed from the cell wall e.g. tragacanth or they are

deposited on the cell wall in successive layers

• When cells containing these substances are mounted in alcohol and

irrigated with water, stratifications (of the successive layers of these

ergastic substances) may often be seen e.g. Mustard and linseed

• Tests

o There are no specific tests for these substances

o The official solution of Ruthenium red

• Stains the mucilage of Senna and Buchu leaves, Althea, Linseed and

Mustard

o Alkaline solution of Corallin

• Stains some forms of mucilage e.g. mucilage from Squill

o Chlor-zinc-iodine or Methylene blue dissolved in alcohol and

glycerine

▪ Stain some mucilage

STEP 6: Tannins (15 minutes)

• Tannins are phenolic compounds obtained from various parts of different

plants

• Tannins are widely distributed in plants

• Occur in solution in cell sap, often in distinct vacuole

• Are abundant in the tree bark, wood, fruit, fruit pod, leaves, and roots

• Tannins are obtained from plants like wattle (Acacia sp.), oak (Quercus

sp.), eucalyptus (Eucalyptus sp.), willow (Salix caprea), pine (Pinus

sp.) etc

• Tannins are found as shapeless yellowish or light brown masses like

powder, flakes or sponge

• Are usually found in large quantities in bark of trees where they act as

a barrier for micro-organisms (bacteria and fungi) and protect the tree

• Tannins are anti-nutrients i.e. lower absorption of e.g. calcium and iron

• Tannins are used as astringent agent in medicines

• Test:

o Sections containing tannins when treated with dilute ferric chloride

are stained bluish-black or greenish colour

STEP 7: Ergastic Crystals (25 minutes)

• Calcium oxalate crystals

o Oxalic acid rarely occurs in free state in plants

o Is extremely common as its calcium salt in the form of crystals

• General forms and sizes of crystals

o The most common forms of crystals encountered are: –

o Prisms e.g. Senna, Hyoscyamus, Quassia, Liquorice, Cascara,

Quillaia, Rauwolfia)

o Rosettes e.g. Rhubarb, Stramonium, Senna, Clove etc.

o Single acicular crystals e.g. Ipecacuanha, Gentian, Cinnamon

o Bundles of acicular crystals e.g. Squill

o Microsphenoidal or sandy crystals e.g. Belladonna

o Cells containing calcium oxalate may differ from the surrounding cells

in size, form or contents and are often referred to as idioblasts

o Tests

▪ They are insoluble in acetic acid and caustic alkali,

▪ Soluble in Hydrochloric and Sulphuric acids without

effervescence

• Calcium carbonate crystals

o Calcium carbonate crystals may be found embedded or incrusted in the

cell walls

o Concentration of calcium carbonate formed on outgrowths of the cell

walls are known as cystoliths

o Families in which calcium carbonate crystals in the orders Urticaceae,

Moraceae, Cannabinaceae (e.g. coriander) etc.

o Well formed cystoliths are seen in the enlarged upper epidermal cells

and in the clothing hairs of the lower epidermis of the leaf of

Cannabis sativa

o Tests

▪ Calcium carbonate crystals can be identified by their property of

dissolving with effervescence in acetic, hydrochloric or sulphuric

acid

▪ If 50% of sulphuric acid is used needle-shaped crystals of calcium

sulphate gradually separate

• Hesperidin and Diosmin

o Occur as feathery-like aggregates or sphaerocrystalline masses in the

cells of many of the Rutaceae (e.g. Lemon and Oranges) and in isolated

plant of other families

• Silica Crystals

o Forms the skeleton of diatoms,

o Occurs as incrustation on cell walls or as masses in the interior of

cells e.g. in the cells of the sclerenchymatous layer of Cardamom seeds

STEP 8: Key Points (5 minutes)

• Ergastic substances are non-living cell contents which can be identified

by microscopical examination or by chemical and physical tests

• Ergastic substances are food reserves or by-products of metabolism

• Ergastic substances are classified as carbohydrates, proteins, fixed oils

and fats, alkaloids, glycosides, gums, mucilages and pectins, volatile

oils and resins, tannins and crystals

STEP 9: Evaluation (5 minutes)

• What are ergastic substances?

• What are the classes of ergastic substances

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 17: Gum, Mucilage and Pectins

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define gum, mucilage and pectins

• Explain natural source, constituents and uses of Tragacanth gum

• Explain natural source, constituents and uses of Acacia gum

• Explain natural source, constituents and uses of Sterculia gum

• Explain natural source, constituents and uses of Psyllium

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Introduction to Gums, Mucilage and Pectins (15 minutes)

• Gums and mucilage have similar constitutuons and on hydrolysis yield a

mixture of sugar and uronic acids.

• Gums are considered to be pathological products formed upon injury of the

plant or owing to unfavourable conditions such as draught, by a breakdown

of cell walls e.g. tragacanth (extracellular formation gummosis)

• They are insoluble in alcohol but dissolve or swell in water

• Conversely, mucilage are generally normal products of metabolism formed

within the cell (intracellular formation) and may represent storage

material, a water storage reservoir or a protection for germinating

seeds.

• They are often found in quantity in the epidermal cells of leaves, e.g

senna, in seed coats (linseed, psyllium etc.) roots (marshmallow) and

barks (slippery elm)

STEP 3: Natural Source, Constituents and Uses of Tragacanth Gum (25

minutes)

• Definition

o Tragacanth is the “air hardened gummy exudate flowing naturally or

obtained by incision, from the trunk & branches of Astragalus gummifer

(Labillardiere) and certain other spp. of Astragalus

o Tragacanth is the gum that exudes immediately after injury of the plant

occurs and is therefore pre-formed in the plant

• Constituents

o Tragacanthin

o Bassorin

o Sugar

o Uronic acids

• Uses

o Used as a suspending agent for insoluble powders

o Binding agent in pills and tablets

o Emulgent

o A binding agent in food industry

STEP 4: Natural Source, Constituents and Uses of Acacia Gum (25 minutes)

• Definition

o Acacia gum is a dried gum obtained from the stem and branches of Acacia

senegal and some other spp of Acacia (Leguminoseae).

• Constituents

o Arabin (Arabic acid)

o Galactose

o Arabinose

o Rhamnose

o Uronic acids

o Oxidase enzyme

|Activity: Buzzing (5 minutes) |

| |

|ASK students to pair up and buzz on the following question for 2 |

|minutes |

| |

|What are the uses of acacia gum in pharmacy? |

| |

|ALLOW few pairs to respond and let other pairs to add on points not |

|mentioned |

| |

|WRITE their response on the flip chart/board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Uses

o Used as a general stabilizer in emulsions

o Used in lozenges

o As demulcent

o Used for treatment of diarrhoea, cough and sore throat

o It is also widely used in food and drink industries

STEP 5: Natural Source, Constituents and Uses of Sterculia Gum (20

minutes)

• Definition

o Sterculia gum is the gummy exudate obtained from the tree, Sterculia

urens (Sterculiaceae).

• Constituents

o Uronic acids

o Partial hydrolysis yields

▪ D-galactose

▪ L-rhamnose

▪ D-galacturonic acid

▪ Acetic acid

• Uses

o Granular grades are used as a bulk laxative (second only to psyllium

seed in use as a bulk laxative).

o Powdered gum is used in lozenges, pastes and denture fixture powders.

STEP 6: Natural Source, Constituents and Uses of Psyllium (20 minutes)

• Definition

o Psyllium consists of the dried, ripe seeds of Plantago afra (Plantago

psyllium), P. indica (P. arenaria) and P. ovata (Plantaginaceae)

• Constituents

o Mucilage

o Fixed oil

o Sugars

o Sterols

o Protein

|Activity: Buzzing (5 minutes) |

| |

|ASK students to pair up and buzz on the following question for 2 |

|minutes |

| |

|What are the uses of psyllium? |

| |

|ALLOW few pairs to respond and let other pairs to add on points not |

|mentioned |

| |

|WRITE their response on the flip chart/board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Uses of Psyllium

o Psyllium is mainly used as a

▪ Dietary fibre to relieve symptoms of both constipation

▪ Mild diarrhea

▪ Occasionally as a food thickener.

▪ Research has shown lowering of blood cholesterol levels in people

with elevated cholesterol,

▪ Lowering of blood glucose levels in people with type 2 diabetes.

STEP 7: Key Points (5 minutes)

• Gums, mucilage and pectins have similar constitutuons and on hydrolysis

yield a mixture of sugar and uronic acids.

• Gums are pathological products formed upon injury of the plant or owing

to unfavourable conditions such as draught, by a breakdown of cell walls

e.g. tragacanth

• Acacia gum is a dried gum obtained from the stem and branches of Acacia

senegal and some other spp of Acacia (Leguminoseae).

STEP 8: Evaluation (5 minutes)

• What is the use of tragacanth in pharmacy?

• What are the uses of Acacia gum?

• What are the reasons for using gums in foods?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 18: Introduction to Alkaloids

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Explain the occurrence and distribution of alkaloids

• Explain naming of alkaloids

• Explain properties of alkaloids

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Occurrence and Distribution of Alkaloids (35 minutes)

• Alkaloids are basic naturally occurring compounds containing one or more

nitrogen atoms usually in a heterocyclic ring and have a marked

physiological action on man or other animals

• Some alkaloids occur in certain families while others only occur in

specific species

• Alkaloids are highly found in apocynaceae, rubiaceae, solanaceae and

papaveracea

• Alkaloids are not found in rosaceae and labiatae families

• Alkaloids are produced by a large variety of organisms, including

bacteria, fungi, plants, and animals

• Most alkaloids are basic (form salts with acids)

• Some alkaloids are not basic e.g. colchicine, piperine, quaternary

alkaloids.

• The nitrogen in some alkaloids is not in a heterocyclic ring e.g.

Ephedrine, Colchicine, Mescaline.

• Alkaloids are rare in lower plants and richer in dicots than in monocots

• Alkaloids may occur in free state (e.g. as free bases), as salts (e.g.

with organic acids), as glycosides, and as alkaloid N-oxides

• Alkaloids may be found in all parts of the plant, in barks, seeds, roots,

fruits, leaves and in latex

• Functions of alkaloids in the plant;

o Protect against insects and herbivores due to their bitterness and

toxicity

o Are final products of detoxification in some cases.

o Source of nitrogen in case of nitrogen deficiency

o Act as growth regulators in certain metabolic systems.

STEP 3: Properties of Alkaloids (35 minutes)

• Physical properties

o Most alkaloids are crystalline solids, a few are amorphous solids e.g.

emetine.

o Some are liquids that are either volatile or non-volatile

o Majority of the alkaloids are colorless but some are colored;

o Alkaloidal bases are soluble in organic solvents and insoluble in water

o Salts of alkaloids are usually soluble in water and, insoluble or

sparingly soluble in organic solvents.

o Alkaloids are bitter tasting

o Many alkaloids are extremely toxic to other organisms.

o Alkaloids exhibit isomerism e.g. optical isomerism i.e L-ephedrine is

3.5 times more active than d-ephedrine

• Chemical properties

o Alkaloids are amines (may be primary, secondary, tertiary and

quaternary)

o Most alkaloids contain oxygen and are solid in nature e.g.

Atropine.

o Alkaloids are decomposed by heat, except Strychnine and Caffeine

o Alkaloids react with acids to form salts

o Dilute alkalis liberate most alkaloids from their salts e.g. NH3

o Some alkaloids are unstable when exposed to light and oxygen

while others are not

STEP 5: Naming of Alkaloids (35 minutes)

• Alkaloids are named by various methods

• Names of alkaloids end by "ine". These names may be derived from:

o Generic plant name – Atropine from Atropa belladonna

o Specific name of the plant – Cocaine from Erythroxylum coca

o Names of loved ones e.g. Cathelenine

o Common name of the plant – Ergotamine from ergot (rye)

o Physiological action of the plant – Emetine producing emesis

• Prefixes and Suffixes used in naming of alkaloids

• Prefixes:

o "Nor-" designates N-demethylation or N-demethoxylation, e.g.

Norpseudoephedrine and Nornicotine.

o "Apo-" designates dehydration e.g. Apomorphine.

o "Iso-, pseudo-, neo-, and epi-" indicate different types of isomers

• Suffixes:

o "-dine" designates isomerism as Quinidine and Cinchonidine.

o "-ine" indicates, in case of ergot alkaloids, a lower pharmacological

activity e.g. Ergotaminine which is less potent than ergotamine

STEP 7: Key Points (5 minutes)

• Alkaloids are basic naturally occurring compounds containing one or more

nitrogen atoms usually in a heterocyclic ring and have a marked

physiological action on man or other animals

• Alkaloids are produced by a large variety of organisms, including

bacteria, fungi, plants, and animals and are part of the group of natural

products

• Alkaloids may occur in free state (e.g. as free bases), as salts (e.g.

with organic acids),

STEP 8: Evaluation (5 minutes)

• What are alkaloids?

• What are the functions of alkaloids in plants?

• Mention physical properties of alkaloids?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 19: Classification, Uses and Extraction of Alkaloids

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Classify alkaloids

• List pharmacological actions and uses of alkaloids

• Explain extraction, purification and isolation of alkaloids from powdered

plants

• Explain chemical tests for alkaloids

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Classification of Alkaloids (40 minutes)

• Alkaloids differ widely in their botanical and biochemical origin, in

chemical structure and their pharmaceutical action

• Therefore, there many different systems for classification of alkaloids

• Major classification systems include

o On the basis of basicity

▪ Alkaloids may be classified into weak bases e.g. caffeine, strong

bases e.g. atropine, amphoteric alkaloids e.g. phenolic alkaloids

like morphine and neutral alkaloids e.g. colchicine

o Biological origin

o Chemical structure

o Biosynthetic pathway

• Classification based on chemical structures (the Hegnauer’s

classification) is more useful and practical

• By the Hegnauer’s Classification, alkaloids are grouped into:

o Typical/True Alkaloids

▪ They are derived from amino acids and contain a nitrogen in a

heterocyclic ring e.g. Atropine

▪ They are toxic

▪ Show a wide range of physiological activity

▪ They are almost invariably basic

▪ They are biosynthesized from amino acids

▪ They normally occur in the plant as salt of an organic acid

▪ Colchicine and quaternary alkaloids are not basic in nature and

do not have heterocyclic ring in their structures

▪ They are divided into the following groups based on their ring

structures

• Pyrrole and Pyrolidine e.g. hygrine, strychnine

• Pyrrolizidine e.g. symphitine, echimidine etc.

• Pyridine and Piperidine e.g. Nicotine etc.

• Tropane (Piperidine/N-methyl-pyrrolidine) e.g. hyoscyamine,

atropine, etc.

• Quinoline e.g. quinine etc.

• Isoquinoline e.g. emetine, morphine, codeine, etc.

• Aporphine (reduced isoquinine/ naphthalene) e.g. boldine

• Quinolizidine e.g. cytisine etc

• Indole or Benzopyrrole e.g. Ergometrine, ergotamine etc.

• Indolizidine e.g. Castanospermine etc.

• Imidazole or Glyoxaline e.g. pilocarpine

• Terpenoid e.g. Aconitine

o Proto-alkaloids/Atypical Alkaloids

▪ Derived from amino acids but do not contain nitrogen in the

heterocyclic ring

▪ They are also called biogenic amines

▪ They are simple amines biosynthesized from amino acids and are

basic

▪ Examples of proto-alkaloids include mescaline, ephedrine,

erythromycin, taxol

o Pseudoalkaloids

▪ They are not derived from amino acids

▪ There are two major series in this class:

• The steroidal alkaloids e.g. Conessine

• The terpenoid alkaloids e.g. Purines, Caffeine, Theophylline and

Theobromine

[pic]

STEP 3: Pharmacological Actions and Uses of Alkaloids (15 minutes)

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What are the uses of alkaloids? |

| |

|ALLOW few students to respond? |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Alkaloids have marked pharmacological activities

o Analgesics and narcotics e.g. morphine and codeine

o CNS stimulants e.g. caffeine and strychnine

o Anticancer activity e.g. vincristine, vinblastine and taxol

o Mydriatics e.g. atropine

o Anti-asthmatic activity e.g. ephedrine

o Antitussive e.g. codeine

o Expectorant effect e.g. lobeline

o Anti-hypertensive e.g. reserpine

o Smooth muscle relaxants e.g. atropine and papaverine

o Skeletal muscle relaxants e.g. d-tubocurarine

o Anthelmintic activity e.g. pelletierine and arecoline

o Antiparasitic action e.g. quinine and emetine

o Antibacterial activity e.g. berberine

STEP 4: Extraction, Purification and Isolation of Alkaloids (25 minutes)

• Stas-Otto Method

o This technique involves the distribution of alkaloid bases between

acid or aqueous solution and immiscible organic solvent

o First Stage

▪ Powdered plant material is moistened with water and mixed with

alkali like sodium and potassium carbonate, ammonia, calcium

hydroxide. A paste is made with water, dried and re-powdered

• The lime combines with acid, tannins and other phenolic

substances and sets free the alkaloids

o Second Stage

▪ The free alkaloids are extracted by hot continuous percolation

with chloroform or other organic solvent

• The free alkaloids dissolve together with other substances

soluble in solvent

o Third stage

▪ Chloroform solution is agitated with successive portions of

dilute sulphuric acid separating the aqueous layer before adding

the next portion

▪ The alkaloids are converted into alkaloidal sulphates, which

being soluble in water, pass into the aqueous layer

o Fourth Stage

▪ The mixed aqueous liquid is made alkaline with ammonia, and

precipitates that form are collected, washed with water and dried

• Ammonia decomposes the alkaloidal sulphates forming ammonium

sulphates, soluble in water and the free alkaloid which being

practically insoluble in water is precipitated

• Volatile alkaloids are extracted by steam distillation i.e.

Plant material + water + Fixed alkali [pic] steam containing

alkaloids

Heat received in

acidic solution

• Alkaloids are purified by;

o Direct crystallization from solvent

o Steam distillation

o Chromatography techniques

o Gradient pH techniques

STEP 5: Chemical Tests for Alkaloids (20 minutes)

• Alkaloids can be identified by chemical tests

• Precipitation reactions:

o Reagents used for carrying out chemical tests for alkaloids

include;

▪ Reagents that form double salts:

• Mayer’s or Valser’s Reagent (Potassium Mercuric Iodide)

o Produces white or yellow colour precipitates

• Dragendorff’s or Krauts Reagents (Potassium Iodide +

bismuth nitrate)

o Produces orange red precipitates

▪ Reagents Containing Halogens:

• Wagner’s Reagent (Iodine-Potassium Iodide)

o Produces brown or reddish-brown precipitates

▪ Organic Acids:

• Hager’s Reagent (Picric Acid)

o Gives yellow crystalline precipitates

• Tannic Acid solution

o Give buff coloured precipitates

• Colour reactions

o Van-Urks test

▪ For ergot alkaloids and gives a blue colour

o Vitali-Morin test

▪ For solanaceous alkaloids and give a violet colour

STEP 6: Key Points (5 minutes)

• Alkaloids differ widely in their botanical and biochemical origin, in

chemical structure and their pharmaceutical action hence classified by

using various methods

• Common chemical tests for presence of alkaloids include; Mayer's reagent

i.e. potassiomercuric iodide solution, Dragendorff's reagent i.e.

solution of potassium bismuth iodide, Wagner’s reagent i.e. iodine in

potassium iodide and Hagers reagent i.e. picric acid

• Alkaloids are tested chemically by using precipitation reactions such as

by using the Wagner’s reagent or by colour reaction tests such as Vitali-

Morin test

STEP 7: Evaluation (10 minutes)

• What are true alkaloids?

• What are proto alkaloids?

• How are alkaloids extracted?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 20: Tropane Alkaloids

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define tropane alkaloids

• Explain natural sources and uses of tropane alkaloids

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Objectives (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Introduction to Tropane Alkaloids (20 minutes)

• Tropane alkaloids are derived from tropine and consist of mandelic,

tropic or benzoic acid esters of tropine

• Chemically they are formed by fusion of pyrrolidine and piperidine ring

with a common methylated nitrogen

o Tropane alkaloids are very closely related to each other

• All tropane alkaloids have pronounced physiological actions

• Tropane alkaloids include:

o Hyoscyamine

o Hyoscine

o Atropine

o Cocaine

• They all occur within the Solanaceae family (except cocaine which occurs

in Erythroxylaceae family)

STEP 3: Natural Sources and Uses of Stramonium (20 minutes)

• Definition

o Stramonium is defined as dried leaves and flowering tops of Datura

stramonium and its varieties, family Solanaceae

o Its synonyms are thornapple, jimson or Jamestown weed

o Drug is required to contain not less than 0.25% of alkaloid calculated

as hyocyamine

o Drug is widely distributed in Africa, Germany, France, Hungary

o Adulterant: Solanum nigrum

o Allied Drugs are Datura inoxia, Datura metel and Datura sanguinea

• Constituents

o Contain 0.2 – 0.45% alkaloids, the major alkaloids are;

▪ Hyoscyamine

▪ Hyoscine

▪ Small quantities of atropine

o Hyoscyamine and hyoscine are found in the ration 2:1 (hyoscyamine:

hyoscine)

o Younger plants contain hyoscine, atropine is little and is formed from

racemization of hyoscyamine

o These alkaloids test positive for Vitali-Morin test

• Uses of Stramonium;

o Hyoscyamine is used to treat urinary tract disorders

o It is used to treat spasms of the bladder

o Hyoscyamine preparations are also used as antispasmodics in the therapy

of peptic ulcers

o Hyoscine hydrobromide is used in pre-operative medication 30 – 60

minutes before induction of anaesthesia

o Hyoscine butylbromide used in irritable bowel syndrome to relief pain

due to abdominal cramps

o It is also used in dysmenorrhea

STEP 4: Natural Sources and Uses of Belladonna (25 minutes)

• Definition

o Consist of the dried leaves and flowering tops of Atropa

belladonna

▪ Its synonym is deadly night shade

▪ Family: Solanaceae

▪ Contains not less than 0.3% of total alkaloids calculated as

hyoscyamine

o Adulterant: Phytolacca dodecandra

o Allied drugs are Indian belladonna and Atropa acuminata

• Constituents

o Contains 0.3 – 0.6% of Tropane alkaloids, the chief of which is

hyoscyamine

o Belladonin

o Small quantities of volatile bases e.g. pyridine and N-

methylpyrroline are present

• Pharmacological Actions

o Atropine

▪ Stimulant on CNS

▪ Dilates eye pupils

▪ Decreases sweating

▪ Produces stomach acid and saliva and relaxes smooth muscle

(asthma and colic)

o Hyoscine

▪ lacks CNS stimulant action of atropine

▪ Sedative – motion sickness

o Atropine and Hyoscine

▪ Used in ophthalmic practice to dilate pupil

• Uses of Belladonna

o Belladonna leaves are used for internal preparations

o Used as sedative, antispasmodic and to check secretions

o Roots are used for external preparations

o Atropine is indicated in organophosphates and carbamate

insecticides poisoning

o It produces mydriatic effect by paralyzing the iris and the

ciliary muscles

o Is it used as an antispasmodic to lessen smooth muscle

spasm/griping

o Used to treat some types of arrhythmias

STEP 5: Natural Sources and Uses of Hyocyamus (20 minutes)

• Definition

o Hyoscyamus leaf consists of the dried leaves or dried leaves and

flowering tops of Hyoscyamus niger, family Solanaceae

o Common name: Henbane

• Constituents:

o Tropane alkaloids mainly:

▪ Hyoscyamine in small amount

▪ Hyoscine (main constituent)

o Allied Drugs are Hyoscyamus albus, Hyosycamus muticus, Hyoscyamus

pusillus, Hyoscyamus aureus

• Uses of Hyocyamus

o Resembles belladonna and stramonium in action but weaker

▪ Higher hyoscine content hence less likely to cause cerebral

stimulation

o Used to relieve spasm of the urinary tract

o Used as a sedative

o Used as an expectorant

o Anti-asthmatic

STEP 6: Natural Sources and Uses of Coca (20 minutes)

• Definition

o Coca is derived from dried leaves of Erythroxylum coca (Bolivian or

Huanuco) and E. truxillense (Peruvian or Truxillo), cultivated in Peru,

Bolivia, Colombia and Indonesia, family Erythroxylaceae

▪ Coca leaves have been used in South America as a masticatory from

very early times

▪ The leaves are artificially or sun-dried and packed in bags.

o Constituents

▪ Coca leaves contain about 0.7 to 1.5% of total alkaloids, of which

cocaine, cinnamylcocaine and α-truxilline are the most important.

▪ These alkaloids occur in different proportions in different

commercial varieties

▪ Other substances are hygrine, hygroline, tropacocaine

o Uses

▪ Local anaesthetic agent

▪ Stimulan

STEP 6: Key Points (5 minutes)

• Tropane alkaloids are very closely related to each other

• Belladonna consists of dried leaves and flowering tops of Atropa

belladonna

• Stramonium is defined as dried leaves and flowering tops of Datura

stramonium and its varieties

• Hyoscyamus leaf consists of the dried leaves or dried leaves and

flowering tops of Hyoscyamus niger

STEP 7: Evaluation (5 minutes)

• What is the source of hyoscyamus?

• What are the uses of atropine?

• What is the use of hyocyamus?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 21: Lobelia and Tobacco

Total Session Time: 60 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define lobelia

• Define Tobacco

• Explain natural sources and uses of lobelia and Tobacco

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Natural Sources and Uses of Lobelia and Tobacco (45 minutes)

• Lobelia

o Lobelia consists of the dried aerial parts of Lobelia inflata

o Common Names: Lobelia, Indian Tobacco

o The plant was traditionally used by the Native Americans for asthma

o Constituents

▪ Lobelia contains about 0.24 – 0.4% of pyrrolizidine alkaloids (BP

1988, not less than 0.25%), the most important of which is lobeline

▪ Other constituents are lobelidine, lobelanine and isolobelanine

o Uses

▪ Treatment of asthma

▪ Chronic bronchitis

▪ In anti-smoking preparations

▪ Injection of lobeline hydrochloride is used in the resuscitation of

new-born infants

|Activity: Buzzing (5 minutes) |

| |

|ASK students to pair up and buzz on the following question for 2 |

|minutes |

| |

|What is tobacco? |

| |

|ALLOW few pairs to respond and let other pairs to add on points not|

|mentioned |

| |

|WRITE their response on the flip chart/board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Tobacco

o Tobacco consists of dried leaves of Nicotiana tobacum, family

Solanaceae

o Tobacco is also known as Tumbakhu

o Constituents

▪ Nicotine

▪ Narcotine

▪ Anabasine

o Uses

▪ Pesticide

▪ Insecticide

STEP 3: Key Points (5 minutes)

• Lobelia herb consists of the dried aerial parts of Lobelia inflate

• Lobelia is used in anti-smoking preparations

• Tobacco is used as insecticide and pesticide

STEP 4: Evaluation (5 minutes)

• What are the uses of Lobelia?

• What are the main constituents of Lobelia?

• What is tobacco?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 22: Quinoline Alkaloids

Total Session Time: 60 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define quinoline alkaloids

• Explain natural sources and uses of alkaloids

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Definition of Quinoline Alkaloids (10 minutes)

• Quinoline consist of alkaloids and alkaloid salts obtained from the bark

of Cinchona species

• Quinolone alkaloids include quinine, quinidine, cinchonine and

cinchonidine

• The amount of alkaloids present depends on the species, environment of

the tree, age, and method of bark collection.

STEP 3: Natural Sources and Uses of Cinchona (25 minutes)

• Definition

o Cinchona bark consist of dried bark of the stem or root of Cinchona

succirubra, Cinchona ledgeriana, Cinchona officinalis and Cinchona

calisaya

o Chinchona belongs to the family Rubiaceae

o The plants are trees indigenous to Colombia Equador, Peru and Bolivia

and are cultivated in Indonesia, India and Tanzania

o There are over 36 known species and hybrids of cinchona

• Constituents

o Contains quinoline alkaloids, the principal quinoline alkaloid are

quinine and quinidine

o Other quinoline alkaloids are quinicine, cinchonicine, cinchotannic

acid and anthraquinones

|Activity: Small Group Discussion (15 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

| |

|What are the uses of Quinine and Quinidine? |

| |

|ALLOW students to discuss for 10 minutes |

| |

|ALLOW few groups to present and the rest to add points not mentioned |

| |

|CLARIFY and SUMMARIZE by using the contents below |

• Uses

o Bitter tonic and stomachic (cinchona extract)

o Used as gargles (tannins in bark – astringent)

o Treatment of malaria

o Prophylaxis of cardiac arrhythmias

o Treatment of atrial fibrillation (quinidine)

STEP 4: Key Points (5 minutes)

• Quinolone alkaloids consist of alkaloids and alkaloid salts obtained from

the bark of Cinchona species

• Cinchona bark consist of dried bark of the stem or root of Cinchona

succirubra, Cinchona ledgeriana, Cinchona officinalis and Cinchona

calisaya

• Important quinolone alkaloids include quinine which is used for treatment

of malaria

STEP 5: Evaluation (5 minutes)

• What is cinchona bark?

• What are the constituents of cinchona?

• Mention the medicinal uses of cinchona

STEP 6: Assignment (10 minutes)

|Activity: Take home Assignment (10 minutes) |

| |

|DIVIDE students in groups or individual. |

| |

|ASK the students to work on the following assignment |

| |

|What is cinchonism? |

|List the sign and symptoms of cinchonism |

| |

|ALLOCATE time for students to do the assignment and submit |

| |

|REFER students to recommended references |

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 23: Isoquinoline Alkaloids

Total Session Time: 60 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define isoquinoline alkaloids

• Explain natural sources and uses of isoquinoline alkaloids

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Definition of Isoquinoline Alkaloids (10 minutes)

• Isoquinoline consist of alkaloids and alkaloid salts obtained from opium

and ipecacuanha

• Both of these alkaloids are in the same group but differ chemically and

in their pharmacological actions

• The amount of alkaloids present depends on the species, environment age,

and method of bark collection

STEP 3: Natural Sources Uses of Opium (15 minutes)

|Activity: Buzzing (5 minutes) |

| |

|ASK students to pair up and buzz on the following question for 2 |

|minutes |

| |

|What is opium? |

| |

|ALLOW few pairs to respond and let other pairs to add on points |

|not mentioned |

| |

|WRITE their response on the flip chart/board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Definition

o Opium (raw opium) is the latex obtained by incision from the unripe

capsules of Papaver somniferum, family papaveraceae

o It is dried partially by spontaneous evaporation and partly by

artificial heat

o It is commercially known as Indian opium.

o According to the BP, opium is intended only as a starting point for the

manufacture of galenicals, and should not be dispensed as such.

• Constituents

o There are 6 main alkaloids produced by opium;

▪ Morphine

▪ Codeine

▪ Thebaine

▪ Noscapine

▪ Narceine

▪ Papaverine

• Uses

o Opium and Morphine are used to relieve pain, as hypnotic, and for

decreasing metabolism

▪ Morphine is a potent analgesic

o Opium

▪ Closely resembles morphine – exerts action more slowly – preferred

to morphine (e.g. in diarrhoea).

▪ Opium is a diaphoretic agent

o Codeine

▪ Milder sedative

▪ Relieve cough

▪ Habitual use may cause constipation

STEP 4: Natural Sources and Uses of Curare (10 minutes)

• Definition

o Curare refers to various South America arrow poisons extracts obtained

from members of Menispermaceae (Stephania) and Loganiaceae

(Chondrodendron tomentosum)

o There are three kinds of curare depending on their containers and

chemical characteristics;

▪ Tube-curare

▪ Packed in bamboo tubes (Brazil and Peru)

▪ The alkaloid was then named “tubocurarine”

▪ Calabash-curare

• Packed in gourds (Guiana, Venezuela and Columbia)

o Pot-curare

• Packed in earthenware pots

• Constituents

o Tubocurarine

o Curarine

• Uses

o Tubocurarine chloride is used to produce muscular relaxation in

surgical operations and neurological conditions

STEP 5: Natural Sources and Uses of Ipecacuahnha (10 minutes)

• Ipecacuanha consists of dried rhizome and roots of Cephalis ipecacuanha

(Brazilian ipec) or Cèphalis acuminata (Costa Rica ipecac), family

Rubiaceae

• Constituents

o Emetine (60-75%)

o Cephaeline,

o Psychotrine

o Psychotrine methyl ether

o Ipecacuanhin

• Other constituents;

o Emetamine

o Psychotrine methylether

o Ipecoside (glycoside)

• The drug also contains crystalline glucosidal tannin (ipecacuanhin,

ipecacuanhic acid) ipecoside, starch and calcium oxalate

• Uses of ipecacuanha

o Expectorant

o Emetic

o Amoebic Dysentry

o Emetine is more expectorant and less emetic in action than

cephaeline

o Psychotrine:

o Selective HIV inhibitors (study could lead to therapeutically

useful agents)

STEP 6: Key Points (5 minutes)

• Isoquinoline alkaloids consist of alkaloids and alkaloid salts obtained

from opium and ipecacuanha

• Opium (raw Opium) is the latex obtained by incision from the unripe

capsules of Papaver somniferum, family papaveraceae

• Curare refers to various South America arrow poisons made from different

plants

STEP 7: Evaluation (5 minutes)

• What is the source of ipecacuanha?

• What are the uses of opium?

• What is the natural source of Opium?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 24: Indole and Imidazole Alkaloids

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define indole and imidazole alkaloids

• Explain natural sources and uses of alkaloid

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• Computer and LCD Projector

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Natural Sources and Uses of Pilocarpus (15 minutes)

• Definition

o Pilocarpus consists of imidazole alkaloids obtained from leaves of

closely related species of Pilocarpus jaborandi and other species of

the genus Pilocarpus, family Rutaceae

o It is also known as Jaborandi

• Constituents

o Pilocarpine

o Isopilocarpine

o Pilocarpidine

o Pilosine

o Pseudopilocarpine

o Isopilosine

• Uses

o Used in form of Pilocarpine Hydrochloride

o It is a physiological antagonist of Atropine

o Used in ophthalmic practices e.g. treatment of glaucoma

o Causes contraction of pupil of the eye

STEP 3: Natural Source and Uses of Vinca Alkaloids (15 minutes)

• Definition

o Vinca alkaloids are oncolytic indoline alkaloids obtained from dried

whole plant of Catharanthus roseus, family Apocynaceae

• Constituents

o Leurocristine (vincristine)

o Vincaleukoblastine (vinblastine)

▪ Vinblastine is converted into vincristine by chemical reactions or

by microbial N-demethylation using Streptomyces albogriseolus

|Activity: Buzzing (5 minutes) |

| |

|ASK students to pair up and buzz on the following question for 2 |

|minutes |

| |

|What are uses of Vinca Alkaloids? |

| |

|ALLOW few pairs to respond and let other pairs to add on points |

|not mentioned |

| |

|WRITE their response on the flip chart/board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Uses

o Vinblastine – treatment of generalized Hodgkin’s disease, lymphocytic

lymphoma, histiocytic lymphoma, advanced testicular carcinoma, kaposi’s

sarcoma, choriocarcinoma and breast cancer unresponsive to therapy

o Vincristine – treatment of acute lymphocytic leukemia in combination

therapy in Hodgkin’s disease, ymphosarcoma, reticulum cell sarcoma,

neuroblastoma and Wilm’s tumour

STEP 4: Natural Sources and Uses of Ergot Alkaloids (15 minutes)

• Definition

o Ergot is the dried sclerotium of a fungus Claviceps purpurea, arising

in the ovary of the rye, Secale cereal, family Hypocreaceae

o The sclerotium arises in the ovary of the rye – secale cereale

• Constituents

o Contains water soluble and water insoluble alkaloids

o Water soluble:

▪ Ergometrine

▪ Ergonovine

▪ Ergometrinine

o Water insoluble:

▪ Ergotamine

▪ Ergotaminine

▪ Ergotoxine

o Derivatives of lysergic acid

▪ Lysergic acid diethylamide (LSD)

• Uses of ergot alkaloids

o Ergometrine is used to control postpartum haemorrhage

o Ergometrine produces oxytocic effects

o Ergotamine and semi-synthetic dihydrohydroxy ergotamine are employed as

specific analgesic for treatment of migraine (caffeine enhances

absorption)

o Lysergic acid derivative, LSD is a psychomimetic (a potent

hallucinogen) controlled under narcotics

STEP 5: Natural Sources and Uses of Nux vomica (15 minutes)

• Definition

o Nux vomica are dried, ripe seeds of Strychnous nux-vomica, family

Loganiaceae

• Constituents

o The Main indole alkaloids are;

▪ Strychnine

▪ Brucine

• Strychnine is more physiologically active than brucine

• Strychnine is present in the inner part of the endosperm while

brucine is in the outer layers

▪ Other alkaloids are:

• α-colubrine, β-colubrine, vomicine, pseudostrychnine and

isostrychnine

o The drug also contains 3% fixed oils, glycoside – loganin

• Uses

o It stimulates peristalsis in chronic constipation and is often combined

with cascara and other laxatives

o Bitter stomachich and tonic (increases gastric juice to improve

appetite and digestion)

o Improves the pulse and raises blood pressure

o At higher doses it is a lethal poison

o Brucine is used commercially as an alcohol denaturant (as it is

extremely bitter)

STEP 6: Natural Sources and Uses of Calabar Beans (15 minutes)

• Definition

o Calabar beans are dried seeds of Physostigma venonosum, family

Leguminosae

o The seeds are extremely hard

• Constituents

o Physostigmine,

o Isophysostigmine,

o Physovenine

o Eserinmine

o Geneserine

• Uses

o A reversible inhibitor of cholinesterase thus enhancing the effect of

endogenous Acetylcholine

o It is used systematically as an antidote for atropine poisoning and

other anticholinergic drugs

o Used in ophthalmology to contract the pupil, to combat mydriasis

o It is used in the treatment of glaucoma

▪ It decreases intra-ocular pressure caused by increased outflow of

the aqueous humour

STEP 7: Natural Sources and Uses of Rauwolfia (15 minutes)

• Definition

o Rauwolfia consist of dried rhizome and roots of Rauwolfia serpentine,

family Apocynaceae

o The drug is commonly known as Indian snake root

o The African rauwolfia consists of dried roots of Rauwolfia vomitoria

widely distributed in tropical Africa

• Constituents

o Major alkaloids are:

▪ Reserpine

▪ Resinnamine

o Other Alkaloids include:

▪ Rauwolfine (Ajmaline)

▪ Ajamalicine

▪ Serpentine

▪ Serpentinine

▪ Yohimbine

o Other constituents:

▪ Unsaturated fatty acids, phytosterols, esters, alcohols and

sugars

o African rauwolfia contains mainly Reserpine and Rescinnamine

• Uses

o It is used as a centrally acting anti-hypertensive agent (reserpine)

▪ Used in very small concentration in combination with other

antihypertensive agents due to its major side effect –suicidal

depression

STEP 8: Natural Sources and Uses of Yohimbe Bark (15 minutes)

• Definition

o Consists of dried bark of Pausinystalia yohimbe (family Rubiaceae)

o Grows in Cameroon

• Constituents

o Chief constituent is Yohimbine

• Use

o As an aphrodisiac agent

o Symptomatic treatment of erectly dysfunction

STEP 9: Key Points (5 minutes)

• Pilocarpus consists of imidazole alkaloids obtained from leaves of

closely related species of Pilocarpus jaborandi and other species of the

genus Pilocarpus

• Vinca alkaloids are oncolytic indoline alkaloids obtained from dried

whole plant of Catharanthus roseus

• Ergot is the dried sclerotium of a fungus Claviceps purpurea, arising in

the ovary of the rye, Secale cereal

STEP 10: Evaluation (5 minutes)

• What in the natural source of vinca alkaloids?

• What are the constituents of ergot alkaloid?

• What are the therapeutic uses of ergot alkaloids?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 25: Purine Alkaloids

Total Session Time: 60 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define purine alkaloids

• Explain natural sources and uses of alkaloids

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD Projector and laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Introduction to Purine Alkaloids (15 minutes)

• Purine alkaloids are derivatives of Xanthines

• They have amphoteric character

• They exhibit peculiar solubility in warm water and in chlorinated

solvents

• These alkaloids include caffeine (seeds of coffee plants, kola plants,

tea leaves and guarana seeds), theobromine (Theobroma cocao) and

theophylline (tea leaves and cola nuts)

• The stimulant action in beverages such as tea and coffee is due to the

purine alkaloids

• Caffeine (1, 3, 7-trimethylxanthine) stimulates CNS and has a weak

diuretic action.

• Theobromine (3,7-dimetylxanthine) produce opposite action to that of

Caffeine

• Theophylline (1,3-dimetylxanthine) relaxes involuntary muscles more

effectively than caffeine or theobromine

STEP 3: Natural Sources and Uses of Alkaloids (30 minutes)

• Cocoa

o Cocoa consists of seeds of Theobroma cacao, family sterculiaceae

o Cocoa is produced in South America (Ecuador, Columbia, Venezuela), West

Indies and West Africa (Nigeria, Ghana and Java)

o Cocoa kernels contain 0.9 – 3% theobromine and the husk 0.19- 2.98% of

this alkaloid

o The seed also contains 0.05 – 0.36% caffeine, cocoa fat/butter,

condensed tannins and volatile compounds

o Main constituents are Theobromine and Theophyllline

o Uses

▪ Theobromine is used

• As base for suppositories (cocoa butter)

• For heart and kidney tonic

• As a drink e.g. cocoa

• As flavouring agent e.g. chocolate

▪ Theophylline

• Relaxes bronchial smooth muscles

• Stimulates respiratory centre in the brain stem by increasing

sensitivity to CO2

• Stimulates the CNS

• Slightly inotropic

• Diuretic activity is stronger than that of caffeine

• Used for relief of cough (bronchodilator)

• Smooth muscle relaxant for symptomatic relief/prevention of

bronchial asthma

• Treatment of reversible bronchospasm associated with chronic

bronchitis and emphysema

• Coffee

o Coffee consists of seeds of coffea arabica and other species of coffee,

family rubiaceae

o Constituents:

▪ Caffeine, tannins, Nicotinic acid, fixed oils and chlorogenic acid

▪ Caffeine eenhances alertness, ffacilitates thought formation and

decreases the sensation of fatigue. At high doses caffeine induces

nervousness, insomnia and tremors.

o Another source of caffeine is Tea, which consists of prepared leaves of

Thea sinensis/Camellia sinensis

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What are the uses of Caffeine? |

| |

|ALLOW few students to respond |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARISE by using the content below |

o Uses

▪ Coffee produce caffeine which is used in combinations with

antipyretics and analgesics, cold and flu medication (increases the

intestinal absorption of some of these drugs or to counteract

drowsiness)

▪ Caffeine is also used as an ingredient in non-alcoholic beverages

and “energizing” beverages

STEP 4: Key Points (5 minutes)

• Purine alkaloids are derivatives of xanthines

• Purine alkaloids exhibit peculiar solubility in warm water

• Main constituents of cocoa are Theobromine and Theophyllline

• Cocoa butter is used a suppository base

STEP 5: Evaluation (5 minutes)

• Mention the cardiovascular use of caffeine

• What are the pharmacological uses of Theophylline?

• What are the uses of Theobromine?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 26: Proto alkaloids

Total Session Time: 60 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define proto-alkaloids

• Explain natural source and uses of proto-alkaloids

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD Projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Introduction to Proto-alkaloids (10 minutes)

|Activity: Brainstorming (3 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What are the characteristics of proto-alkaloids? |

| |

|ALLOW few students to respond |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Proto-alkaloids do not have nitrogen as part of the heterocyclic ring

• Proto-alkaloids include ephedrine adrenaline,

• Both cause dilation of the bronchi, increase heart rate and peripheral

vasoconstriction

STEP 3: Natural Sources of Proto-alkaloids (35 minutes)

• Ephedra

o Ephedra is a protoalkaloid obtained from dried young stems of Ephedra

gerardiana and Ephedra nebrodensis, family Ephedraceeae

o Its synonym is Ma-Huang

o Constituents

▪ Ephedrine

▪ Nor-ephedrine

▪ Pseudoephidrine

▪ N-methylephedrine

o Uses

▪ Included in asthma, colds, flu and Hayfever medications

• It is a bronchodilator

• Action is more prolonged than adrenaline

• Need not be given by injection, but can be administered orally

• Allopathic: Sinumed (dries a runny nose)

• Used as an anti-inflammatory.

• Used for weight loss

• Increases metabolism

• Decreases appetite

• CNS stimulant – acts on adrenergic receptors

• Colchicum

o Colchicum is the dried ripe seeds of Colchicum luteum and Colchicum

autumnale.

o Family: Liliaceae

o Constituents

▪ Colchicine (main constituent)

▪ Demecolcine

o Uses

▪ Relieves gout (used with caution – professional supervision)

▪ Also used in biological experiments to produce polyploidy

(multiplication of the chromosomes in a cell nucleus) in

horticulture and cultivation of medicinal plants

STEP 4: Key Points (5 minutes)

• Proto-alkaloids do not have nitrogen as part of the heterocyclic ring

• Ephedra is a protoalkaloid obtained from dried young stems of Ephedra

gerardiana and Ephedra nebrodensis

• Ephedrine is a bronchodilator which is included in asthma, colds, flu and

hay fever medications

STEP 5: Evaluation (5 minutes)

• What is the natural source of Ephedra?

• What are the uses of ephedrine?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 27: Introduction of Glycosides

Total Session Time: 60 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Explain the meaning of glycosides

• List the characteristics of glycosides

• Classify glycosides

• List functions of glycosides in the plants

Resources Needed

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Meaning and Characteristics of Glycosides (15 minutes)

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What is a glycoside? |

| |

|ALLOW few students to respond |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARIZE by using the content below |

← Glycosides are molecules in which a sugar part (sugar moiety called the

glycone) is bound to a non-sugar part (non-sugar moiety called the

aglycone) joined together by glycosidic bond

← Glycosides play numerous important roles in living organisms

← Many plants store important chemicals in the form of inactive

glycosides

← Many such plant glycosides are used as medications

← Characteristics of glycosides include;

o Glycosides are soluble in water but insoluble in organic solvents

▪ The glycone part is water soluble but insoluble in the organic

solvents

▪ The aglycone part is water insoluble but soluble in the organic

solvents

▪ Some glycosides are soluble in alcohol

o Glycosides are ccolorless (except flavonoid- yellow, anthraquinone-red

or orange)

o They are solid, amorphous and nonvolatile

o They give a positive reaction with Molisch's and Fehling's solution

test (after hydrolysis).

o Most glycosides have bitter taste

o They are oodorless except saponin (glycyrrhizin).

o Glycosides with lots of sugars have increased solubility in water

o Glycosides hydrolyzed by using mineral acids and temperature or by

using enzymes

STEP 3: Classification of Glycosides (30 minutes)

← Glycosides can be classified base on the following basis:

o Based on therapeutic effects

▪ Cardiac glycosides, Laxative glycosides etc.

o Based on glycone moiety

▪ Rhamnosides, glucorhamnosides, rhamnoglucosides etc.

o Based on glycosidic linkage/bond

▪ O-glycosides, s-glycosides, N-glycosides, C-glycosides

o Based on chemical nature of the aglycone

▪ Alcoholic and phenolic glycosides

▪ Anthraquinone glycosides

▪ Coumarin glycosides

▪ Cyanogenic glycosides

▪ Flavanoidal glycosides

▪ Steroidal glycosides

▪ Thioglycosides

STEP 4: Key Points (5 minutes)

← Glycosides are made up of a glycone and aglycone moieties

← Glycosides are water soluble

← Glycosides are hydrolysed by acids, bases and acids into their

components

STEP 5: Evaluation (5 minutes)

← What is a glycoside?

← What are characteristics of glycosides

← What are the classes of glycosides

References:

Gleadow, RM; Møller, BL (2014). "Cyanogenic glycosides: synthesis,

physiology, and phenotypic plasticity". Annual Review of Plant

Biology. 65: 155–85. doi:10.1146/annurev-arplant-050213-

040027. PMID 24579992.

Sun, Hong-Xiang; Xie, Yong; Ye, Yi-Ping (2009). "Advances in saponin-based

adjuvants". Vaccine. 27 (12): 1787–1796. doi:10.1016/j.vaccine.01.091.

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 28: Cardiac Glycosides

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define cardiac glycosides

• List properties of cardiac glycosides

• Mention natural sources of cardiac glycosides

• Explain mechanisms of action

• Differentiate types of cardiac glycosides

• Explain chemical tests for cardiac glycosides

• Mention general uses of cardiac glycoside

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD Projector and Lapatop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Properties of Cardiac Glycosides (30 minutes)

• Cardiac glycosides are a group of glycosides with powerful action on

cardiac muscles (positive ionotropic effect on the heart)

• Cardiac glycosides are also made up of aglycone and glycone moities

• The Glycone part

o consists of one or more monosaccharide units

o contains a steroid nucleus and a lactone ring

• The Aglycone part

o has steroidal nucleus

o is always attached at C-3 position of aglycone part

• There are two groups of cardiac glycosides;

o Cardenolides

▪ The cardenolides have an unsaturated butyrolactone ring –a five

membered-ring e.g. strophanthus

o Bufadienolides

▪ In this group the lactone ring is a 6 membered (pyrrone) ring

▪ These are obtained from animal sources e.g. Bufadieonolides

from toads

• Characteristics of Cardiac Glycosides;

o Amorphous

o Odorless

o Bitter tasting

o Soluble in water

o Insoluble in organic solvents

o Very toxic compounds

• Chemical tests for cardiac glycosides

o Keller Kilian test

▪ Cardiac glycoside + CH3COOH + H2SO4 + FeCl3, produces brown

colour

o Legal test

▪ Cardiac glycoside + pyridine Sodium Nitroprusside, produces

red to pink colour

STEP 3: Sources, Constituents and Uses of Selected Cardiac Glycosides (60

minutes)

• Digitalis

o Definition

▪ Digitalis consists of dried leaves of Digitalis lanata or Digitalis

purpurea (common name purple fox glove), family Scrophulariaceae

▪ Digitalis – finger-like corolla

▪ Purpurea – purple colour

o Constituents

▪ D. purpurea produces primary glycosides

• Purpurea glycoside A

• Purpurea glycoside B

• Glucogitaloxin

▪ On drying, enzyme degradation taken place with the loss of the

terminal glucose to produce;

• Digitoxin from purpurea glycoside A

• Gitoxin from purpurea glycoside B

• Gitaloxin

o D. lanata produces

▪ Digoxin

▪ Lanatosides A, B and C

• During drying: acetyl terminal sugar can be lost

• Deacetylation produces primary glycosides as those produced

by Digitalis purpurea

• Lanatoside A produces Purpurea glycoside A

• Lanatoside B produces Purpurea glycoside B

• Lanatoside C produces Deslanoside C/ Deacetyllanatoside

o Uses of digitalis

▪ Digitalis glycosides are used for the treatment of;

• Congestive Heart Failure (CHF)

• Arrhythmias

• Atrial fibrillations

• Squill

o Definition

▪ Squill consists of the dried sliced bulbs of Urgenea maritima, from

which the membrenous outer scales have been removed (family

Liliaceae)

▪ The common name for squill is “sea onion”

▪ There are two types of squill; red squill and white squill

o Constituents

▪ Squill contains the glycosides;

• Scillaren A

o Which is crystalline in form

• Scillaren B

o An amorphous mixture of glycosides

• The red squill contains Scillirosides in addition to the

other glycosides

o Uses

▪ White squill

• As cardiotonic drugs

• As diuretics agents

• In small dose –as expectorant agents

• In large dose –as emetic agents

▪ Red squill

• Used as a rodenticide (due to Scillirosides)

• Strophanthus

o Definition

▪ Consist of the dried ripe seed of Strophanthus kombe/strophanthus

hispidus, family apocynaceae

o Constituents

▪ Mixture of glycosides

• K-strophanithin, erysimoside, K strophanthoside and

cymarin

• Fixed oils, resins and mucilage are also present

• K-strophanthosides;

o Composed of the genin strophanthidin

o Coupled to a trissaccharide with cymarose, β-glucose

and α-glucose

o Are short-acting cardiac glycosides

STEP 4: Mechanism of Action for Cardiac Glycosides (15 minutes)

• Cardiac glycosides act by;

o Inhibition of Na+/K+ ATPase of the cardiac cells, which increases the

intracellular Na+ ions levels

o The increased Na+ ion levels within the cardiac cells inhibits the

Na+/Ca2+ exchanger, this in turn, results in increased concentrations

of Ca2+ within the cardiac cells

o The increased intracellular Ca2+ increases contractile force of the

cardiac muscles

[pic]

STEP 5: Key Points (5 minutes)

• Cardiac glycosides are glycosides with powerful positive inotropic action

on cardiac muscles

• Digitalis consists of dried leaves of Digitalis lanata or Digitalis

purpurea

• Digoxin is obtained from Digitalis lanata

• Digitalis glycosides are used for the treatment of heart conditions

including congestive heart failure (CHF), arrhythmias and atrial

fibrillations

STEP 10: Evaluation (5 minutes)

• What is the source of digoxin?

• What is the main use of digoxin?

• What is strophanthus?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 29: Anthraquinone Glycosides

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define anthraquinone glycosides

• Explain natural sources and uses of Senna

• Explain natural sources and uses of Cascara

• Explain natural sources and uses of Aloe

• Explain natural sources and uses of Rhubarb

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD Projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Introduction to Anthraquinone Glycosides (20 minutes)

• Are glycosides in which the aglycone portion contains an anthracene ring

structure and attached to glycone portion

• They are found in drugs such as cascara, rhubarb, senna, aloes

• They are used as cathartics or stimulant laxative

• They act by increasing the tone of the smooth muscle in the walls of the

colon and stimulate the secretion of water and electrolytes

STEP 3: Natural Sources and Uses of Senna (20 minutes)

• Definition

o Senna consists of the dried leaflets of Casssia senna (Alexandrian

senna) and Cassia angustifolia (Tinnevelly senna), family Fabaceae

(Leguminosae)

o Cassia senna is indigenous to tropical Africa and is cultivated in

Sudan

o Cassia angustifolia is indigenous to Somaliland, Arabia, Pujab and is

cultivated in South India

• Constituents

o The basic constituents of senna are the anthraquinone glycosides;

▪ Sennoside A

▪ Sennoside B

o Other constituents include;

▪ Aloe-emodin

▪ Rhein

• Uses

o Laxative

▪ Senna is a useful purgative either for habitual constipation or on

occasional use

▪ Senna increases the peristaltic movements of the colon by its local

action upon the intestinal wall

STEP 4: Natural Sources and Uses of Cascara (20 minutes)

• Definition

o Cascara consists of the dried bark of Rhamnus purshianus, family

Rhamnaceae

o Requires long storage to destroy compounds called anthrones in the

fresh bark, which cause vomiting

• Constituents

o Cascaroside A

o Cascaroside B

o Cascaroside C

o Cascaroside D

o Tannins

o Volatile oils

• Uses

o Purgative

▪ Used in the form of liquid extract/elixir/as tablets prepared

from dry extract

STEP 5: Natural Sources and Uses of Aloe (25 minutes)

|Activity: Buzzing (5 minutes) |

| |

|ASK students to pair up and buzz on the following question for 2 |

|minutes |

| |

|What are Aloes? |

| |

|ALLOW few pairs to respond and let other pairs to add on points not|

|mentioned |

| |

|WRITE their response on the flip chart/board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Definition

o Aloes consists of a solid residue obtained by evaporating the liquid

which drains from the transversely cut leaves of various species of

aloe, family Liliaceae

o The species that yield aloe are:

▪ Aloe barbadensis

▪ Aloe ferox

▪ Aloe perryi

▪ Aloe vera

• Constituents

o The most important constituents of Aloes are the two Aloins:

▪ Barbaloin

▪ Isobarbaloin

• Barbaloin is the major constituent of the plant

o Other constituents are resins and Aloe-emodin

• Uses

o Stimulant purgative

o Anthelminthic

STEP 6: Natural Sources and Uses of Rhubarb (20 minutes)

• Definition

o Rhubarb consists of the dried underground parts of Rheum palmatum or R.

officinale, family Polygonaceae

• Constituents

o Rhubarb contains free anthraquinone

▪ Rhein

▪ Emodin

▪ Aloe-emodine

▪ Emodin monomethylether

• Uses

o Rhubarb can be used as a strong laxative

o Rhubarb has an astringent effect on the mucous membranes of the mouth

and the nasal cavity

STEP 7: Key Points (5 minutes)

• Anthraquinones are glycosides in which the aglycone portion contains an

anthracene ring structure and attached to glycone portion

• Anthraquinone glycosides are obtained from sources including cascara,

rhubarb, senna, aloes

• Anthraquinone glycosides are generally used as cathartics or laxatives

STEP 8: Evaluation (5 minutes)

• What are the therapeutic uses of Rhubarb?

• What are the constituents of Senna leaf?

• Mention the uses of aloe vera?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 30: Introduction to Volatile Oils and Resins

Total Session Time: 120 minutes

Prerequisites

None

Learning Tasks

By the end of this session students are expected to be able to:

• List characteristics of volatile oils

• Describe the composition of volatile oils

• Classify volatile oils

• Describe extraction of volatile oils

• List therapeutic uses of volatile oils

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD Projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Characteristics of Volatile Oils (25 minutes)

• Volatile oils, also known as essential oils, are concentrated,

odoriferous liquids that entirely or almost entirely volatile in steam

• Volatile oils are referred to as "essential" in the sense that they carry

a distinctive scent, or essence of the plant

• Essential oils do not as a group need to have any specific chemical

properties in common, beyond conveying characteristic fragrances

(Essential oils should not be confused with essential fatty acids)

• Volatile oil originates from plants, possess a unique odour or flavour,

mainly used in perfumes and flavourings

• Essential oils have the following general characteristics

o They evaporate under atmospheric pressure at room temperature

o They are soluble in alcohol and other organic solvents

o They are insoluble in water

o They have high refractive index

o They are optically active

o Most of them are colourless or pale yellow

o They are odoriferous

o They are sensitive to air (resinify on exposure to air)

o Most of them are terpenoid in nature

• Resins

o Resins are hydrocarbon secretions of many plants, more or less solid

amorphous products of complex chemical nature

o Resin produced by most plants is a viscous liquid

o Resins may be associated with volatile oils or gum or may be found in

irregular masses which are insoluble in water but soluble in alcohol

o Resins, oleoresins (resins associated with oils) and gum resins (resins

associated with gums) are usually secreted into secretory cavities or

ducts

STEP 3: Composition of Volatile Oils (20 minutes)

|Activity: Brainstorming (10 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

| |

|What is composition of volatile oils? |

| |

|ALLOW students to discuss for 15 minutes |

| |

|ALLOW few groups to present and the rest to add points not |

|mentioned |

| |

|CLARIFY and SUMMARIZE by using the contents below |

• Volatile oils are chemically derived from terpenes (mainly from mono and

sesqui terpenes)

o Terpenoids are hydroxycarbons of plant origin with general formula

(C5H8) n i.e. isoprene units

o Terpenoids are naturally occurring and give plants and flowers their

fragrance

• Many oils are terpenoid in origin, some oils such as cinnamon and clove

contain principally aromatic (benzene) derivatives mixed with terpenes

• With the exception of oils derived from glycosides (e.g. bitter almond

oil and mustard oil), volatile oils are mixtures of hydrocarbons and

oxygenated compounds derived from these hydrocarbons

• Some oils are acyclic, aromatic or contain sulphur or nitrogen

• In some oils (e.g. Oil of turpentine) the hydrocarbons predominate and

only limited amount of oxygenated constituents are present, other

volatile oils (e.g. Oil of cloves) the bulk of the oil consists of

oxygenated compounds

STEP 4: Classification of Volatile Oils (15 minutes)

• Volatile oils can be classified based on extraction method into;

o Concretes

▪ Uses solvent e.g. hexane and waxes or resins to contact the plant

materials and then the solvent removed by gent heating e.g. jasmine

oil

o Pomades

▪ Obtained by enfleurage (hot or cold) e.g. oils from flowers

o Resinoids

▪ Extraction with resinous materials i.e. to prolong effect of

fragrance

o Absolutes

▪ Remains after alcoholic extraction from pomades or concretes

• Volatile can be classified on the basis of their functional groups into;

o Hydrocarbon volatile oils e.g. turpentine

o Alcoholic volatile oils e.g. peppermint, cardamom and coriander oils

o Aldehydic volatile oils e.g. lemon oil, orange oil, cinnamon

o Ketonic volatile oils e.g. camphor, spearmint oils

o Phenolic volatile oils e.g. clove, anise, nutmeg oils

o Phenolic ether volatile oils e.g. fennel oil

o Oxide volatile oils e.g. rosemary oil

STEP 5: Extraction of Volatile Oils (30 minutes)

• The following methods are used as general extractions for volatile oils;

o Distillation

▪ Water (Simple) distillation (for dry plant materials, materials not

destroyed by boiling e.g. turpentine oil)

▪ Water and steam distillation (for dry plant materials not destroyed

by direct heating e.g. clove and cinnamon oils)

▪ Steam distillation (for fresh plant materials e.g. peppermint and

spearmint oils)

• Simple steam distillation

• Saturated steam distillation

• Hydrodifusion

o Scarification

▪ Sponge extraction

▪ Ecuelle method

▪ Enzymatic hydrolysis

o Soxhlet extraction

o Solvent extraction

▪ Extraction by non-volatile solvents

• Enfleurage (hot or cold)

• Maceration

• Spraying or pneumatic method

o Extraction by volatile solvents

o Uses light petroleum followed by distillation

▪ Extraction by supercritical gases

• Mainly using carbon dioxide gas

• Each of the extraction method has advantages and disadvantages

o Choice of a suitable method is very important

STEP 6: Therapeutic Uses of Volatile Oils (15 minutes)

|Activity: Small Group Discussion (10 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

| |

|List down the therapeutic uses of volatile oils? |

| |

|ALLOW students to discuss for 15 minutes |

| |

|ALLOW few groups to present and the rest to add points not |

|mentioned |

| |

|CLARIFY and SUMMARIZE by using the contents below |

• Therapeutic uses of volatile oils include;

o Topically as irritants

o Used for improving circulation

o Used for preparation of lotions and liniments

o Used as carminative agents

o Used as local anaesthetic

o Used for respiratory problems e.g. cough, asthma

o Some volatile oils have antibacterial and antifungal effects

o Some volatile oils have anthelminthic activity

STEP 7: Key Points (5 minutes)

• Volatile oils or essential oils are odoriferous liquids that entirely or

almost entirely volatile in steam

• Volatile oils are chemically derived from terpenes (mainly from mono and

sesqui terpenes

• Volatile oils are classified according to their functional groups or by

methods of extraction

STEP 8: Evaluation (5 Minutes)

• Define volatile oil

• What are classes of volatile oils

• What are the methods used in extraction of volatile oils

References

Oxford English Dictionary , 2014),"essential oil". (online, American

English ed.). Archived from the original, Retrieved 2014-07-21.

Ryman, Daniele (1984). The Aromatherapy Handbook: The Secret Healing Power

of Essential Oils. Century Publishing CO. Ltd. pp. Chapter 3.

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 31: Alcoholic and Hydrocarbon Volatile Oils

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Describe peppermint oil

• Describe cardamom oil

• Describe coriander oil

Resources Needed

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD Projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Peppermint Oil (25 minutes)

• Definition

o Peppermint oil is an oil that has a strong peppermint odour and

produces a cooling sensation in the mouth obtained by distillation

from dried leaves and flowering tops of Mentha piperita L. (Fam.

Labiatae)

• Constituents

o Menthol

o Menthone

o Methyl acetate

o The official oil is required to contain 4.5 – 10% of esters calculated

as methyl acetate, not less than 44% of free alcohols calculated as

menthol and 15-32% of ketones calculated as menthone

• Uses

o Peppermint, and is used chiefly as a flavouring agent and as a

carminative

o Treatment of common cold, cough, inflammation of the mouth and throat,

sinus infections, and respiratory infections

o Treatment of digestive problems including heartburn, nausea, vomiting,

morning sickness, irritable bowel syndrome, cramps of the upper

gastrointestinal tract and bile ducts, upset stomach, diarrhea,

bacterial overgrowth of the small intestine, and gas

o Peppermint oil is also used for headache, muscle pain, nerve pain,

toothache, inflammation of the mouth, joint conditions, itchiness (the

oil is a counterirritant), allergic rash, bacterial and viral

infections, relaxing the colon during barium enemas, and for repelling

mosquitoes

o Used as a flavouring agent

o It has carminative action

STEP 3: Cardamom Oil (25 minutes)

• Definition

o Cardamom oils is an oil obtained from dried ripened seeds of Elettaria

cardamomum, family Zingiberaceae

• Constituents

o Terpinol

o Terpinyl acetate

o Borneol

o Fixed oils

• Uses

o Flavouring agent

o Carminative

o Gastrointestinal stimulant

o Used in dyspepsia and flatulence

STEP 4: Coriander Oil (25 minutes)

• Definition

o Coriander oil is an oil obtained from fresh leaves and dried seeds of

Coriander sativum, family Umbeliferae

• Constituents

o d-pinene

o fixed oil

o Calcium oxalate

|Activity: Buzzing (10 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

| |

|What are the uses of coriander oils? |

| |

|ALLOW students to discuss for 5 minutes |

| |

|ALLOW few groups to present and the rest to add points not |

|mentioned |

| |

|CLARIFY and SUMMARIZE by using the contents below |

• Uses

o Flavouring agent

o Carminative agent

o Stimulant

STEP 5: Turpentine Oil (25 minutes)

• Definition

o Turpentine oil is an oil obtained by distilation from Pinus palustris

and other species of Pinus e.g. Pinus longifolia, family Pinaceae

o The oil is colourless with characteristic odour and highly flammable

o The oil is re-distilled with NaOH to form rectified oil of turpentine

• Constituents

o ( and (- Pinene

o Methylcarbachol

o Camphene

• Uses

o Counter irritant

o Local irritant

o Rectified oil is used internally as a diuretic, urinary antiseptic,

anthelminthic and expectorant

STEP 7: Key Points (10 minutes)

• Peppermint oil is an oil that has a strong peppermint odor and produces a

cooling sensation in the mouth obtained by distillation from dried leaves

and flowering tops of Mentha piperita

• Peppermint, and is used chiefly as a flavouring agent and as a

carminative

• Turpentine oil is an oil obtained by distilation from Pinus palustris

and other species of Pinus belonging to family Pinaceae

STEP 8: Evaluation (5 minutes)

← What are the uses of peppermint oil?

← What is the use of coriander oil?

← What is the source of cardamom oil?

References

Ryman, Daniele (1984). The Aromatherapy Handbook: The Secret Healing Power

of Essential Oils. Century Publishing CO. Ltd. pp. Chapter 3.

Soares, I., Loreto, É, Rossato, L., Mario, D., Venturini, T., Baldissera,

F., Alves, S. (2015). In vitro activity of essential oils extracted

from condiments against fluconazole-resistant and -sensitive Candida

glabrata. Journal De Mycologie Médicale,25(3), 213-217. doi:10.1016/j.

mycmed.2015.06.003

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 32: Ketonic and Aldehydic Volatile Oils

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Describe Spearmint Oil

• Describe Camphor Oil

• Describe Lemon Oil

• Describe Orange Oil

• Describe Cinnamon Oil

Resources Needed

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD Projector and laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Spearmint Oil (20 minutes)

• Definition

o Spearmint oil is an aromatic essential oil obtained by steam

distillation of the dry/fresh leaves and flowering tops of Mentha

spicata

• Constituents

o Carvone

o Limonene

o Phellandrenes

o Esters

o Official oil should contain not less than 55% of carvone

• Uses

o As a carminative agent

o As a flavouring agents in pharmaceutical preparations and foods

STEP 3: Camphor Oil (20 minutes)

• Definition

o Camphor is an oil obtained by distillation of wood of stem ad root of

Cinnamomum camphora

o Brown and yellow camphor oil has high safrol levels and are toxic and

carcinogenic

• Constituents

o Main constituents include α-pinene, camphene, β-pinene, sabinene,

phellandrene, limonene, geraniol, safrole, cinnamaldehyde, eugenol,

methyl cinnamate

• Uses

o Analgesic

o Antidepressant

o Anti-inflammatory

o Antiseptic

o Diuretic, febrifuge, anti-hypertensive, insecticide, laxative,

rubefacient, stimulant and vermifuge

o It is also used in cosmetics

STEP 4: Lemon Oil (20 minutes)

|Activity: Buzzing (5 minutes) |

| |

|ASK students to pair up and buzz on the following question for 2 |

|minutes |

| |

|What is lemon oil? |

| |

|ALLOW few pairs to respond and let other pairs to add on points not|

|mentioned |

| |

|WRITE their response on the flip chart/board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Definition

o Lemon oil is an oil obtained by expression from the fresh peel of the

fruits of Citrus limon

• Constituents

o Vitamin C

o Limonene

o Flavonoids

o Glycosides

o Citronellol

o Hisperidine

• Uses

o Carminative

o Aromatic

o Flavouring agent

STEP 5: Orange Oil (20 minutes)

• Definition

o Orange oil is an essential oil obtained by expression from the rind

(peels) of bitter orange (Citrus aurantium) and sweet orange (Citrus

sinensis) family Rutaceae

• Constituents

o Vitamin C

o α-pinene

o Sabinene

o Limonene

o Myrcene

o Linanool

o citronellal

o Neral

o Geranial

o Calcium oxalate

• Uses

o Carminative

o Flavouring agent

o Antiseptic

o Anti-depressant

o Antispasmodic

o Anti-inflammatory agent

o Carminative agent

o Cholagogoue

o Diuretic

o Sedative

o Tonic

STEP 6: Cinnamon Oil (20 minutes)

• Definition

o Cinnamon oil is an oil obtained from dried inner bark of the shoot of

Cinnamomum loureirii, family Lauraceae

▪ The outer bark is scrapped off and inner bark removed with care

from hard wood as quill

o Constituents

▪ Cinnamic acid

▪ Cinnamaldehyde

▪ Caryophylline

▪ Resins

▪ Tannins

▪ Mucillages

▪ Calcium oxalate

o Uses

▪ As flavouring agent

▪ Carminative agent

▪ Diuretic

STEP 7: Key Points (10 minutes)

• Spearmint oil is an aromatic essential oil obtained by steam distillation

of the aerial structures of Mentha spicata

• Orange oil is an essential oil obtained by expression from the rind

(peels) of an orange fruit, Citrus sinensis family Rutaceae

• Camphor is an oil obtained by distillation of wood of stem ad root of

Cinnamomum camphora

STEP 8: Evaluation (5 minutes)

← What are the uses of lemon oil?

← What is orange oil?

← What are therapeutic uses of cinnamon oil

References

Ryman, Daniele (1984). The Aromatherapy Handbook: The Secret Healing Power

of Essential Oils. Century Publishing CO. Ltd. pp. Chapter 3.

Soares, I., Loreto, É, Rossato, L., Mario, D., Venturini, T., Baldissera,

F., Alves, S. (2015). In vitro activity of essential oils extracted

from condiments against fluconazole-resistant and -sensitive Candida

glabrata. Journal De Mycologie Médicale,25(3), 213-217.

doi:10.1016/j.mycmed.2015.06.003

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 33: Phenolic ether, Phenolic, Oxide and Ester Volatile Oils

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Describe fennel oil

• Describe anise oil

• Describe clove oil

• Describe eucalyptus oil

• Describe lavender oil

• Describe rosemary oil

• Describe dill oil

Resources Needed

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD projector and laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Fennel Oil (15 minutes)

• Definition

o Fennel oil is an oil obtained from dried ripened seeds of Foeniculum

vulgare family Umbelliferae

• Constituents

o Anethole

o Fenchone

• Uses

o Carminative

o Stimulant

o Flavouring agent

STEP 3: Anise Oil (15 minutes)

• Definition

o Anise oil is an oil distilled from dried ripened fruit of Pimpenella

anisum, family Umbelliferae

• Constituents

o Anethole

o Safrole

o Fixed oils

• Uses

o Carminative

o Stimulant

o Flavouring agent

STEP 4: Clove Oil (15 minutes)

• Definition

o Clove oil is a colourless or pale yellow oil obtained by distillation

from dried flower buds of Eugenia caryophyllus (or Syzygium

aromaticum), family Myrtaceae

o The oil is sensitive to air

• Constituents

o Eugenol

o Acetyleugenol

o Gallotamic acid

o Carvacrol

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What are uses of clove oil? |

| |

|ALLOW few students to respond? |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Uses

o Stimulant

o Carminative

o Irritant

o Condiment

o Local anaesthetic

o Analgesic

o Antiseptic

o Flavouring agent

STEP 4: Eucalyptus Oil (15 minutes)

• Definition

o Eucalyptus oil is an oil obtained by distilled from the fresh leaves of

Eucalyptus globlus, family Myrtaceae

o The oil is colourless or pale yellow with aromatic (camphoraceous)

odour

• Constituents

o Eucalyptol

o Cineol

o Resins

o Tannins

o Eucalyptic acid

• Uses

o As an expectorant agent

o Rubefacient

o Antiseptic

o Decongestant

o Diaphoretic

STEP 5: Lavender Oil (15 minutes)

• Definition

o Lavender oil is an oil obtained by steam distillation from flowering

tops of Lavandulla officinalis (Family Lamiaceae)

o The oil is colourless or pale yellow in colour with light fresh aroma

• Constituents

o α-pinene

o Limonene

o Linalyl acetate

• Uses

o As an antiseptic agent

o Used to relieve tension, depression, panic hysteria and nervous

exhaustion

o Used for headache, migraines and insomnia

o Relives pain associated with rheumatism, arthritis, lumbago and muscles

o It is employed pharmaceutically in the anti-arthropod preparation of

Gamma Benzene Hexachloride

o Relives problems associated with gastrointestinal tract including

nausea, vomiting, colics and flatulence

STEP 6: Rosemary Oil (15 minutes)

• Definition

o Rosemary oil is an oil obtained from flowering tops of Rosmarinus

officinalis (family Lamiaceae)

• Constituents

o Rosmarinic acid

o Camphor

o Caffeic acid

o Betulinic acid

o Rosmaridiphenol

• Uses

o As an antioxidant

o Relief of gastrointestinal problems including heartburn, flatulence and

loss of appetite

o Used for gout, cough, headache, toothache, high blood pressure, and

reducing age-related memory loss (It is a memory enhancer)

o It is also used topically for preventing and treating baldness, eczema

and promotion of wound healing

o It is also used as an insect repellent

STEP 6: Dill Oil (15 minutes)

• Definition

o Dill oil is an essential oil obtained by distillation from dried leaves

and seeds of Anethum graveolens, family Apiaceae

o The oil has a grass smell

• Constituents

o Carvone

o Limonene

• Uses

o Carminative

o Flavouring agent

o Used with water to create dill water

STEP 7: Key Points (5 minutes)

• Lavender oil is an oil obtained by steam distillation from flowering tops

of Lavandulla officinalis (Family Lamiaceae)

• Fennel oil is an oil obtained from dried ripened seeds of Foeniculum

vulgare

• Rosemary oil is an oil obtained from flowering tops of Rosmarinus

officinalis

• Dill oil is an essential oil obtained by distillation from dried leaves

and seeds of Anethum graveolens

STEP 8: Evaluation (5 minutes)

← What is the chief constituent of clove oil?

← What are the constituents of dill oil?

← What is dill water?

References

Ryman, Daniele (1984). The Aromatherapy Handbook: The Secret Healing Power

of Essential Oils. Century Publishing CO. Ltd. pp. Chapter 3

Soares, I., Loreto, É, Rossato, L., Mario, D., Venturini, T., Baldissera,

F., Alves, S. (2015). In vitro activity of essential oils extracted

from condiments against fluconazole-resistant and -sensitive Candida

glabrata. Journal De Mycologie Médicale,25(3), 213-217.

doi:10.1016/j.mycmed.2015.06.003

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 34: Introduction to Fixed oils and Fats

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define fixed oils and fats

• Explain the distribution and occurrence of fixed oils and fats

• List methods for extraction of fixed oils and fats

• Explain the evaluation of fixed oils and fats

• List uses of fixed oils and fats

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD Projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Distribution and Characteristics of Fixed Oils and Fats (25

minutes)

• Occurrence

o Fixed oils and fats are lipids (esters) of long chain fatty acids and

alcohol

o Fixed oils and fats are widely distributed and occur in both vegetative

and reproductive structures

o They are found often in seeds, where they may replace the carbohydrate

as reserve food material

o They are also associated with protein reserves

o As lipids, fats form an essential component of biological membranes

o Fixed oils occur in plant materials as small highly refractive drops

o Oil globules associated with aleurone grains can be well seen in

cotyledons of linseed and colocynth, and in the endosperm of nux vomica

• Physical Characteristics

o Fixed oils and fats are soluble in ether-alcohol, few exceptions such

as castor oil are sparingly soluble in alcohol

o At ordinary temperature fats are semisolid/ solid and fixed oils are

liquid at normal temperature

o Most vegetable oils are liquid at ordinary temperature but animal fats

are solid

o There are exceptions, e.g. coconut oil, in temperate temperature is

solid and tropic temperature it is liquid oil

• Chemical Characteristics

o They are esters of long chain fatty acids and alcohols or closely

related derivatives of alcohols

o The fatty acids forming the oils can be saturated or unsaturated

o Most animal products contain saturated fatty acids while most plant

products contain unsaturated fatty acids

o A special group of unsaturated fatty acids (the ω-3fatty acids) are

vital to human health as they lower cholesterol levels in the body

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What are the chemical tests for fixed oils and fats? |

| |

|ALLOW few students to respond? |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Fixed oils and fats are coloured brown or black with a 1% solution of

Osmic acid

• In dilute tincture of Alkanna, fixed oils and fats slowly turn red

• Saponification reaction

• A cold mixture of equal parts of a saturated solution of potash and

strong solution of ammonia slowly saponifies fixed oils and fats

resulting in observable characteristic soap crystals

STEP 3: Extraction of Fixed Oils and Fats (25 minutes)

• Processes that are employed in the extraction of oil from raw materials

depends on the botanical source of the oil

• Important processes include;

o Decortication –crushing to remove seed coat

o Expression – kernels are placed onto the oil presses and subjected to

pressure with or without application of heat

o Filtration – separates oil from other matters and may be done several

times to attain purity.

o Steaming -at high temperature to inactivate proteins and other

materials e.g. castor oil requires steaming

• Extraction methods used for fixed oils and fats include;

o Expression (cold or hot)

o Solvent extraction

STEP 4: Evaluation of Fixed Oils and Fats (30 minutes)

• Each kind of fixed oil or fat has a specific standard used for evaluation

o Physical standards include;

▪ Specific gravity

▪ Melting point

▪ Refractive index

▪ Optical rotation

▪ Color

▪ Odor

• Chemical standards include;

o Acid Value

o Saponification Value

o Iodine value

o Ester value

STEP 5: Uses of Fixed Oils and Fats (25 minutes)

|Activity: Small Group Discussion (10 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

|What are the uses of fixed oils and fats? |

| |

|ALLOW students to discuss for 10 minutes |

| |

|ALLOW few groups to present and the rest to add points not mentioned|

| |

|CLARIFY and SUMMARIZE by using the contents below |

• They are used in preparation of suppositories

• They are used in tablet coating

• They are employed as emulsifying agents

• They have therapeutic uses e.g. laxatives etc.

STEP 6: Key Points (5 minutes)

• Fixed oils and fats are esters of long chain fatty acids and alcohol

• At ordinary temperature fats are semisolid/ solid and fixed oils are

liquid at normal temperature

• Fixed oils and fats are coloured brown or black with a 1% solution of

Osmic acid

STEP 7: Evaluation (5 minutes)

• What are the physical standards for fixed oils and fats

• What is saponification value?

• What are the uses of fixed oils and fats?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 35: Castor, Olive, Cod-liver and Peanut Oils

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Explain natural source, constituents and uses of Castor oil

• Explain natural source, constituents and uses of Olive oil

• Explain natural source, constituents and uses of Cod liver oil

• Explain natural source, constituents and uses of Peanut oil

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD Projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Natural Source, Constituents and Uses of Castor Oil (30 minutes)

|Activity: Buzzing (5 minutes) |

| |

|ASK students to pair up and buzz on the following question for 2 |

|minutes |

| |

|What is Castor oil? |

| |

|ALLOW few pairs to respond and let other pairs to add on points not |

|mentioned |

| |

|WRITE their response on the flip chart/board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Definition

o Castor oil is a monounsaturated fixed oil obtained from ripe seeds of

Ricinus communis, family Euphorbiaceae

o Castor seeds are decorticated and the kernels separated from the testa

and cold-expressed in hydraulic presses

o The oil is pale yellow or almost colorless, transparent

• Constituents

o The seeds contain 45-55% fixed oil, 20% protein, ricin (toxic

alkaloid), recinine and several enzymes e.g. lipase

• Uses

o Stimulant cathartic for total colonic evacuation prior to surgery

o Emollient

o Employed in manufacture of soaps

o Hydrogenated oil is used as a stiffening agent in some pharmaceutical

formulations

STEP 3: Natural Source, Constituents and Uses of Olive Oil (25 minutes)

• Definition

o Olive oil is a fixed oil obtained from the ripe fruit of Olea europoae

family Oleaceae

o The oil is an evergreen tree and fruits are drupes, purple when ripe

o Oil is pale yellow/light greenish yellow, slight odor, taste is bland

to faintly acrid

• Constituents

o Linoleic acid

o Oleic acid

o Palmitic acid and

o Stearic acid

• Uses

o Externally as demulcent & emollient agent

o Laxatives

o Used as a purgative administered after food poisoning

STEP 4: Natural Source, Constituents and Uses of Cod-liver Oil (25

minutes)

• Definition

o Cod-liver oil is a fixed oil from the fresh livers of cod fish, Gadus

morrhua, family Gadidae

o The oil is a mixed triglyceride, mainly unsaturated C16-22 acids and

decahexanoic acid

• Constituents

o Omega 3 fatty acids

o Vitamin A

o Vitamin D

• Uses

o Prevention and cure of rickets

o Important source of vitamin A and D

o For treatment of pain and stiffness of joint in arthritis

STEP 5: Natural Source, Constituents and Uses of Peanut Oil (25 minutes)

• Definition

o Peanut oil or arachis oil is a fixed oil obtained from seeds of Arachis

hypogaea (Leguminosae)

o Seeds contain 40-50% oil

• Constituents

o Oleic acid 60%

o Linoleic acid 24%

o Palmitic acid 9%

o Arachidonic acid

• Uses

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What are the uses of Arachis oil? |

| |

|ALLOW few students to respond? |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARISE by using the content below |

• Dietary supplements

• Pharmaceutically solvent for intravenous and intramuscular injections

STEP 6: Key Points (5 minutes)

• Castor oil is monounsaturated fixed oil obtained from ripe seeds of

Ricinus communis

• Olive oil (also known as salad oil, sweet oil) are fixed oil from the

ripe fruit of Olea europoae

• Arachis oil is obtained from seeds of Arachis hypogaea

• Cod-liver oil is a fixed oil from the fresh livers of cod fish, Gadus

morrhua, and it is used as a supplement for vitamin A and D

STEP 7: Evaluation (5 minutes)

• What are constituents of cod liver oil?

• What are the uses of arachis oil?

• What are the uses of Castor oil?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 36: Almond, Linseed, Coconut and Cottonseed Oils

Total Session Time: 60 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Explain natural source, constituents and uses of Almond oil

• Explain natural source, constituents and uses of Linseed oil

• Explain natural source, constituents and uses of Coconut oil

• Explain natural source, constituents and uses of Cottonseed oil

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD Projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Natural Source, Constituents and Uses of Almond Oil (15 minutes)

• Definition

o Almond oil is a fixed oil obtained by expression from kernels of Prunus

amygdalus, family Rosaceae Var dulcis (sweet almond) or P. amygdalus

Var amara (bitter almond)

o The oil is pale yellow liquid with a slight odour and bland, nutty

taste

• Constituents

o Oleic acid

o Linolenic acid

o Amygdalin (bitter almond)

• Uses

o Vehicle in oily injections

o Laxative

o Volatile oils are flavouring agents

STEP 3: Natural Source, Constituents and Uses of Linseed Oil (10 minutes)

• Definition

o Linseed oil (or flaxseed oil) is a fixed oil obtained from the dried,

ripe seed of Linum usitatissimum (flaxseed), family Linaceae

• Constituents

o Palmitic acid

o Stearic acid

o Alpha linoleic acid (ALA)

o Oleic acid

• Uses

o Used in lowering blood cholesterol levels (due to presence of ALA),

control blood pressure

o Used in treatment of inflammation associated with gout

o Controls constipation

o It is an important drying oil in the paint and varnish industry

STEP 4: Natural Source, Constituents and Uses of Coconut Oil (10 minutes)

• Definition

o Coconut oil is a fixed oil obtained by expression or extraction from

the seeds of Cocos nucifera (Palmae)

o The oil is pale yellow to colourless liquid which may have an odour of

coconut

• Constituents

o Lauric acid (chief constituent)

o Myristic acid

o Stearic acid

o Caproic acid

o Capric acid

o Caprylic acid

o Palmitic acid

• Uses

|Activity: Buzzing (5 minutes) |

| |

|ASK students to pair up and buzz on the following question for 2 |

|minutes |

| |

|What are the uses of Coconut oil? |

| |

|ALLOW few pairs to respond and let other pairs to add on points not |

|mentioned |

| |

|WRITE their response on the flip chart/board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Uses of coconut oil include;

o Pharmaceutically in ointment base

o Cosmetically as a moisturizer

o Also used in making soap, candles, chocolate, candies etc.

STEP 5: Natural Source, Constituents and Uses of Cottonseed Oil (10

minutes)

• Definition

o Cotton seed oil is a fixed oil expressed from seeds of Gossypium

hirustum family Malvaceae

• Constituents

o Oleic acid

o Linoleic acid

o Palmitic acid

o Stearic acid

• Uses

o Solvent in injections

o Used in the manufacture of soaps

STEP 6: Key Points (5 minutes)

• Coconut oil is the fixed oil obtained from the seeds of Cocos nucifera

(Palmae)

• Almond is used as vehicle in oily injections and as laxative agent

• Cottonseed oil is obtained from expressed seeds of Gossypium hiruslum

STEP 7: Evaluation (5 minutes)

• What are the natural source of Coconut oil

• What are the uses of cottonseed oil?

• What are the uses of Linseed oil?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 37: Fats

Total Session Time: 60 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define fats

• Explain natural source, constituents and uses of Wool fats

• Explain natural source, constituents and uses of Lanolin

• Explain natural source, constituents and uses of Lard

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD Projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Definition of Fats (15 minutes)

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What are fats? |

| |

|ALLOW few students to respond |

| |

|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARIZE by using the content below |

• Fats are natural oily substances occurring in animal bodies, especially

deposited as a layer under the skin or around internal organs

• They are a group of natural esters of glycerol and various fatty acids,

which are solid at room temperature and are the main constituents of

animal and vegetable fat

STEP 3: Natural Source, Constituents and Uses of Lanolin and Wool Fats

(20 minutes)

|Activity: Small Group Discussion (10 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following questions |

|What is lanolin and wool fats? |

| |

|ALLOW students to discuss for 10 minutes |

| |

|ALLOW few groups to present and the rest to add points not |

|mentioned |

| |

|CLARIFY and SUMMARIZE by using the contents below |

• Definition

o Lanolin is a purified fat-like substance prepared from the wool of the

sheep Ovis aries, family Bovidae

o Lanolin is also known as hydrous wool fat

o Wool fat is a pale yellow substance with a characteristic odor obtained

after purification, bleaching and dehydration of lanolin

• Constituents

o Both lanolin and wool fat are rich in cholesterol, isocholesterol and

unsaturated monohydric alcohols

• Uses

o Emollient base for creams and ointments

o Major component of most ointments

STEP 4: Natural Source, Constituents and Uses of Lard (10 minutes)

• Definition

o Lard is a purified internal fat of the hog, Sus scrofa

o Prepared from the abdominal fat

o Obtained by treatment with hot water.

o Lard is soft, white fat with a non-rancid odor.

• Constituents

o Lard contains 40% solid glycerides such as myristin and 60% of mixed

liquid glycerides such as olein

• Uses

o In preparation of ointments and perfumes

STEP 5: Key Points (5 minutes)

• Fat is any of a group of natural esters of glycerol and various fatty

acids, which are solid at room temperature and are the main constituents

of animal and vegetable fat.

• Wool fat is used as an emollient base for creams and ointments

• Lard is an abdominal fat obtained from purified internal fat of the hog,

Sus scrofa

STEP 6: Evaluation (5 minutes)

• What is the natural source of wool fat?

• What is the use of lanolin in pharmacy?

• What is lard?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

Session 38: Waxes

Total Session Time: 60 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Define wax

• Explain natural sources, constituents and uses of wax

• Explain natural sources, constituents and uses of Carnauba wax

• Explain natural sources, constituents and uses of Bees wax

• Explain natural source, constituents and uses of Spermaceti

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• LCD Projector and Laptop

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Introduction to Waxes (10 minutes)

• Waxes are natural mixtures of esters derived from higher monohydric

alcohols e.g. ceryl and myricyl alcohols, cholesterols and phytosterols

combined with of high molecular weight straight-chain acids

• They are a mixture of esters and acids but do not contain esters of

glycerol

• Simply, waxes are mixtures of different molecular weight acids and

alcohols

• Saponification of waxes is through treatment alcoholic caustic alkali

• Waxes may contain paraffins

• Waxes are found in plants and animals

• Wax has a melting point above approximately 45°C, differentiating waxes

from fats and fixed oils

o Fats and oils may be saponified by means of either aqueous or alcoholic

alkali but waxes are only saponified by alcoholic alkali

o This fact is used for the detection of fats when added as adulterants

to waxes

• The general uses of waxes are as hardening agents in ointments and

cosmetic creams

• Waxes are also used for protective coating in industry and arts

STEP 3: Natural Sources, Constituents and Uses of Carnauba Wax (5

minutes)

• Definition

o Carnauba wax is a wax obtained from the leaves (cuticle) of Copernicia

cerifera (Palmae)

• Constituents

o The wax consists of alkyl esters of wax acids mainly myricyl cerotate

• Uses

o Tablet coatings

STEP 4: Natural Sources, Constituents and Uses of Bees Wax (20 minutes)

|Activity: Small Group Discussion (10 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

|What is the constituents and uses of bees waxes |

| |

|ALLOW students to discuss for 10 minutes |

| |

|ALLOW few groups to present and the rest to add points not mentioned|

| |

|CLARIFY and SUMMARIZE by using the contents below |

• Definition

o Bees wax is the purified wax from the honeycomb of the bee Apis

mellifera (Apidae)

o Is secreted in cells of abdomen of worker bees

o It is solid varying in colour from yellow to greyish brown

• Constituents

o 80% of myricyl palmitate (myricin)

o 15% free cerotic acid an aromatic substance cerolein, hydrocarbons,

lactones, cholesteryl esters and pollen pigments

• Uses

o Yellow bees wax is used

▪ as stiffening agents in yellow ointments

▪ as a base in plasters

▪ in the manufacture of candles and cosmetics and polish

o White bees wax (bleached, purified yellow wax)

▪ Used in pharmaceutical ointments and in creams

STEP 5: Natural Source, Constituents and Uses of Spermaceti (10 minutes)

• Definition

o Spermaceti is a solid wax obtained from mixed oils derived from the

head and blubber of the sperm whale Physeter macrocephalus and the

bottle-nosed whale, Hyperoodon rostratus.

• Constituents

o The wax is white translucent, crystalline masses consists of alkyl

(cetyl) esters with cetyl palmitate, cetyl myristate, acetyl laurate

and cetyl laurate

• Uses

o Emollient agent

STEP 6: Key Points (5 minutes)

• Waxes are natural mixtures of esters derived from higher monohydric

alcohols e.g. ceryl and myricyl alcohols, cholesterols and phytosterols

combined with of high molecular weight straight-chain acids

• Waxes melt at higher temperatures than fixed oils and fats

• Carnauba wax is obtained from the leaves (cuticle) of Copernicia cerifera

(Palmae)

STEP 7: Evaluation (5 minutes)

• What is the natural source of Beeswax?

• What are the uses of yellow beeswax

• What is the use of wax?

References

Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans

pharmacognosy. London: Saunders.

Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical

Press

Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.

Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).

Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &

Wilkins.

Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.

D. (2012). Fundamentals of pharmacognosy and phytotherapy. Edinburgh:

Churchill Livingstone/Elsevier.

———————–

PST 05210 Basic Pharmacognosy

NTA Level 5 Semester 2

March 2019

Rhizodermis

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