Betaglucosides

Beta-glucosides are a broad class of glycosides in which a molecule of β-D-glucose is bound to an aglycone via a β-D-glucosidic linkage. The glucose moiety is typically in the pyranose form, and the bond to the aglycone is formed at the anomeric carbon with a beta orientation. This category encompasses many natural products in which glucose serves as a solubility-enhancing, storage, or activation group.

In plants, beta-glucosides are common storage or defense compounds. Notable examples include salicin, a β-D-glucoside of salicyl alcohol found in willow bark; arbutin, a hydroquinone β-D-glucoside; and phloridzin, a β-D-glucoside of phloretin found in apples and related species. Amygdalin is a well-known cyanogenic β-D-glucoside occurring in bitter almonds and some stone fruits. Isoflavone and flavone glycosides, such as genistin, also belong to this category.

Biochemical processing of beta-glucosides involves beta-glucosidases, which hydrolyze the glycosidic bond to release glucose and the aglycone. This hydrolysis can activate biological activity, release toxic or defensive compounds in plants after tissue damage, or enable metabolism in animals and humans. Biosynthesis of beta-glucosides in plants typically proceeds via glycosyltransferases that transfer UDP-glucose to the aglycone, forming the characteristic beta-glycosidic linkage.