glycosidesnatural

Glycosides are natural products in which a sugar moiety, called glycone, is bound to a non-sugar aglycone via a covalent glycosidic linkage. The bond is typically O-glycosidic, but C-glycosides also occur and are more resistant to hydrolysis. The sugar part can be glucose, but other sugars such as rhamnose, galactose, or arabinose are common. The aglycone may be a phenolic, terpenoid, steroid, or other structure.

Natural glycosides are widespread in plants and occur in some microbes and animals. They often serve defensive roles against herbivores or pathogens, act as storage reservoirs of bioactive aglycones, or participate in signaling. Enzymatic or acid hydrolysis releases the sugar and aglycone, frequently modulating biological activity.

Major classes include cardiac glycosides (cardenolides and bufadienolides) used in heart medicine; cyanogenic glycosides that can release toxic hydrogen cyanide when hydrolyzed; saponin glycosides that produce foaming and display surfactant and pharmacological properties; anthraquinone and flavonoid glycosides typical of many medicines and foods; and numerous glycosides of terpenoids and steroids.

In pharmacology and chemistry, glycosylation can alter solubility, stability, and bioavailability of the aglycone and can influence target interactions. Analytical work often involves hydrolysis to determine sugar and aglycone components, or spectroscopic and chromatographic methods to characterize intact glycosides.