Page 126 - Medicinal Plants_PharmD general
P. 126
The following are the important groups of glycosides:
1. Phenolic glycosides:
The aglycones of this group of glycosides contain phenolic groups and
frequently together with either alcoholic groups or carboxylic groups e.g.
of these phenolic glycosides are arbutin and salicin.
Arbutin is the main active constituent of Uva ursi leaves and is used as
diuretic and antiseptic in urethritis and cystitis.
Test for arbutin
OC6H11O5 H2O OH
+HCl C6H12O6 +
OH OH
Arbutin Hydroquinone
Upon hydrolysis of arbutin with dilute acid, it yields crystals of
hydroquinone (aglycone).
2. Anthracene glycosides or anthraquinone glycosides:
Definition:
A number of glycosides in which the aglycones are anthracene
derivatives occur as the pharmacologically active constituents of several
cathartics of plant origin e.g. cascara and senna. Anthracene derivatives
occur in vegetable drugs in different forms at different oxidation levels i.e
they may occur as derivatives of:
a) Anthraquinone. b) Anthrone.
c) Oxanthrone. d) Dianthrone.
-126-
