Introduction to Alkaloids
Session 18: Introduction to Alkaloids
Total Session Time: 120 minutes
Prerequisites
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 |35 minutes |Presentation |Occurrence and Distribution of |
| | | |Alkaloid |
|3 |35 minutes |Presentation |Naming of Alkaloids |
|4 |35 minutes |Presentation |Properties of Alkaloids |
|5 |05 minutes |Presentation |Key Points |
|6 |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 objectives and clarify
ASK students if they have any questions before continuing.
STEP 2: Occurrence and Distribution of Alkaloids (35 minutes)
nitrogen atoms usually in a heterocyclic ring and have a marked
physiological action on man or other animals
specific species
papaveracea
bacteria, fungi, plants, and animals
alkaloids.
Ephedrine, Colchicine, Mescaline.
with organic acids), as glycosides, and as alkaloid N-oxides
fruits, leaves and in latex
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)
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.
3.5 times more active than d-ephedrine
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 Some alkaloids are unstable when exposed to light and oxygen
while others are not
STEP 5: Naming of Alkaloids (35 minutes)
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
Norpseudoephedrine and Nornicotine.
o "Iso-, pseudo-, neo-, and epi-" indicate different types of isomers
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)
nitrogen atoms usually in a heterocyclic ring and have a marked
physiological action on man or other animals
bacteria, fungi, plants, and animals and are part of the group of natural
products
with organic acids),
STEP 8: Evaluation (5 minutes)
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.
Churchill Livingstone/Elsevier.
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