3Oglycosides

3-O-glycosides are a class of glycosides in which a sugar moiety is linked to the aglycone via an O-glycosidic bond at the 3-position of the aglycone, a common arrangement in flavonoids and related phenolics. The sugar can be a single monosaccharide such as glucose or a disaccharide such as rutinose, and linkages may vary in stereochemistry and position on the sugar.

These compounds are widespread in plants and arise through the action of plant glycosyltransferases, which attach sugars to hydroxyl groups on aglycones. Glycosylation often increases solubility, stabilizes the aglycone, and modulates storage, transport, and bioavailability. In plants, 3-O-glycosides can act as storage or transport forms and may influence color, bitterness, and defense responses. In humans, they commonly occur in the diet as forms of flavonoids and can be hydrolyzed in the gut to release active aglycones.

Common examples include isoquercitrin (quercetin 3-O-glucoside), astragalin (kaempferol 3-O-glucoside), and rutin (quercetin 3-O-rutinoside). These illustrate the diversity of sugar moieties that can be attached at the 3-position. Analytical studies typically rely on high-performance liquid chromatography and mass spectrometry, often following enzymatic or acid hydrolysis to identify the aglycone and sugar components.

Overall, 3-O-glycosides are an important structural and functional class of plant secondary metabolites, influencing solubility, stability, and bioactivity, with relevance in nutrition, pharmacology, and phytochemistry.