Definition of Glycosides
Glycosides are compounds consisting of a sugar moiety (glycone) linked to a non-sugar aglycone via a glycosidic bond.
Aglycones can be terpenoids, phenols, or alkaloids.
Structure and Classification
Based on aglycone:
Flavonoid Glycosides: Flavonoid aglycone.
Cardiac Glycosides: Steroid or triterpenoid aglycones.
Saponins: Triterpenoid or steroid aglycones with soap-like properties.
Cyanogenic Glycosides: Release hydrogen cyanide upon hydrolysis.
Additionally classified by sugar type (e.g., glucose, rhamnose) and glycosidic bond type.
Biosynthesis
Formed by glycosyltransferase enzymes attaching sugar moieties to aglycones, altering solubility, stability, and bioactivity.
Occurrence in Nature
Common in plants for defense, pigmentation, and storage. Also found in some animals and microorganisms.
Biological Activities and Uses
Pharmacological Effects: E.g., cardiac glycosides like digoxin for heart conditions.
Defense Mechanisms: Toxins or deterrents against pests.
Industrial Uses: Natural colorants and antioxidants in food and cosmetics.
Examples
Rutin: Flavonoid glycoside with antioxidant properties in various fruits and vegetables.
Glycyrrhetinic Acid: Saponin glycoside from licorice root, used in flavorings and as an anti-inflammatory agent.