Anthraquinone Glycosides
Session 29: Anthraquinone Glycosides
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 |5 minutes |Presentation |Introduction, Learning Tasks |
|2 |20 minutes |Presentation |Introduction to Anthraquinone |
| | | |Glycosides |
|3 |20 minutes |Presentation |Natural Sources and Uses of Senna |
|4 |20 minutes |Presentation |Natural Sources and Uses of |
| | | |Cascara |
|5 |25 minutes |Buzzing |Natural Sources and Uses of Aloe |
| | |Presentation | |
|6 |20 minutes |Presentation |Natural Sources and Uses of |
| | | |Rhubarb |
|7 |5 minutes |Presentation |Key Points |
|8 |5 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: Introduction to Anthraquinone Glycosides (20 minutes)
structure and attached to glycone portion
colon and stimulate the secretion of water and electrolytes
STEP 3: Natural Sources and Uses of Senna (20 minutes)
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
o The basic constituents of senna are the anthraquinone glycosides;
o Other constituents include;
o Laxative
occasional use
action upon the intestinal wall
STEP 4: Natural Sources and Uses of Cascara (20 minutes)
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
o Cascaroside A
o Cascaroside B
o Cascaroside C
o Cascaroside D
o Tannins
o Volatile oils
o Purgative
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 |
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:
o The most important constituents of Aloes are the two Aloins:
o Other constituents are resins and Aloe-emodin
o Stimulant purgative
o Anthelminthic
STEP 6: Natural Sources and Uses of Rhubarb (20 minutes)
o Rhubarb consists of the dried underground parts of Rheum palmatum or R.
officinale, family Polygonaceae
o Rhubarb contains free anthraquinone
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)
anthracene ring structure and attached to glycone portion
rhubarb, senna, aloes
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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