Introduction to Volatile Oils and Resins
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:
Resources Needed:
SESSION OVERVIEW
|Step |Time |Activity/ |Content |
| | |Method | |
|1 |05 minutes |Presentation |Introduction, Learning Tasks |
|2 |25 minutes |Presentation |Characteristics of Volatile Oils |
| | | |and Resins |
|3 |20 minutes |Presentation |Composition of Volatile Oils |
| | |Brainstorm | |
|4 |15 minutes |Presentation |Classification of Volatile Oils |
|5 |30 minutes |Presentation |Extraction of Volatile Oils |
|6 |15 minutes |Presentation |Therapeutic Uses of Volatile Oils |
| | |Small group | |
|7 |05 minutes |Presentation |Key Points |
| 8|05 minutes |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: Characteristics of Volatile Oils (25 minutes)
odoriferous liquids that entirely or almost entirely volatile in steam
a distinctive scent, or essence of the plant
properties in common, beyond conveying characteristic fragrances
(Essential oils should not be confused with essential fatty acids)
mainly used in perfumes and flavourings
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
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 |
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
contain principally aromatic (benzene) derivatives mixed with terpenes
oil and mustard oil), volatile oils are mixtures of hydrocarbons and
oxygenated compounds derived from these hydrocarbons
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)
o Concretes
materials and then the solvent removed by gent heating e.g. jasmine
oil
o Pomades
o Resinoids
fragrance
o Absolutes
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)
o Distillation
destroyed by boiling e.g. turpentine oil)
by direct heating e.g. clove and cinnamon oils)
spearmint oils)
o Scarification
o Soxhlet extraction
o Solvent extraction
o Extraction by volatile solvents
o Uses light petroleum followed by distillation
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 |
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)
almost entirely volatile in steam
sesqui terpenes
methods of extraction
STEP 8: Evaluation (5 Minutes)
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.
Churchill Livingstone/Elsevier.
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