Cglucoside

C-glucoside, or C-glucoside, refers to a class of glycosides in which a glucose moiety is attached to an aglycone via a carbon–carbon bond rather than the typical oxygen linkage found in most glycosides. This C–C linkage is formed by specialized enzymes known as C-glycosyltransferases, primarily in plants, and it renders the molecule more resistant to hydrolysis by acids and by glycosidases compared with O-glycosides.

Natural occurrence and examples: C-glucosides occur in various plant secondary metabolites, especially flavonoids and isoflavonoids. The best-known example is puerarin, the 8-C-glucoside of daidzein, isolated from the roots of Pueraria lobata (kudzu). Other C-glucosides have been described in different plant species and may involve attachment at positions such as C-6, C-7, or C-8 on the aglycone core.

Biogenesis and chemistry: Glucose is donated by UDP-glucose in reactions catalyzed by C-glycosyltransferases; the resulting C–C bond yields a hydrolysis-resistant glycoside. The inherent stability of C-glucosides to hydrolysis makes them relatively persistent in planta and in some processed foods and medicinal preparations. The chemistry of C-glycosylation is a focus of ongoing research, including enzyme mechanism and substrate scope.

Applications and significance: C-glucosides are of interest for their chemical stability and potential pharmacological properties. Puerarin, for example, has been studied for antioxidant, anti-inflammatory, and potential neuroprotective activities, though findings vary by context. Research continues on biosynthesis, enzymology, and the ecological role of C-glycosides in plant defense and metabolite diversity.