Define Glycosides. Classify it on the basis of Glycosidic linkage with example.
Glycosides are organic compounds of plant and animal origin which yield on either acidic or
enzymatic hydrolysis, one or more sugars and non-sugar residue.
Classification on the basis of glycosidic linkage: ( any 3 classes of the following with 1
example of each)
i) O- glycosides: They are very commonly in higher plants. They are hydrolysed by treatment
of acid or alkali into aglycone and sugar.
e.g. Senna, Rhubarb.
ii) C- glycosides: They are not hydrolysed by heating with dilute acids or alkalies, but by
oxidative hydrolysis with ferric chloride.
e.g. Aloe, Cascara
iii) S- glycosides: they are occurring only in isothiocyanate type of glycoside. They are formed
by interaction of sulfhydryl group of aglycone and hydroxy group of glycone moiety.
e.g. Black mustard.
iv) N- glycosides : N- glycoside is nucleosides where amino group of base react with hydroxyl
group of base ribose or deoxyribose and ultimately give N- glycosides form.
e.g. Cinchona