Page 135 - PG 504-theoretical notes-phyto-1-2024-2025..

Clinical pharmacy PharmD program Third level Phytochemistry-1 (PG-504)

Definition

The term glycoside , however, applies to every compound that arises from the union
of:

a sugar with a ny hydroxyl compound through the hemi - acetal hydroxyl group of
the sugar.

Other definitions

• Glycosides are formed by the linkage of the reducing group of a sugar molecule
to a non-sugar molecule.

• Glycosides are non-reducing organic compounds that on hydrolysis yield:

1. A sugar part (glycone) and

2. A non-sugar part (aglycone, also called genin).

Hydrolysis of Glycosides

1. Acid hydrolysis:

• Cleavage of the glycosidic linkage upon heating with dilute acids to give
the free sugar and genin.
• C-glycosides differs from other classes in non-hydrolysable by acids or
enzymes.

CH OH Hydrolysis CH OH
2
2
+ C H O 6
6
12
O C H O 5 OH
6
11

The Glycoside The Genin The Glycone
116
(Salicin) (Saligenin) (Glucose)