Cglycosidic
C-glycosidic bonds, or C-glycosides, are a class of covalent linkages in which a sugar unit is attached to an aglycone through a carbon–carbon bond rather than through an oxygen atom. In this arrangement, the anomeric carbon (usually C-1) of the sugar forms a direct C–C bond to a carbon on the aglycone, yielding a stable, non-oxygenated linkage that is distinct from the more common O-glycosidic bonds found in many natural products and drugs.
This bond type is found predominantly in plant secondary metabolites, especially flavonoids and related polyphenols. C-glycosides
Notable examples include flavonoid C-glycosides such as apigenin-6-C-glucoside, known as isovitexin, and luteolin-6-C-glucoside, known as isoorientin.
Biosynthesis and occurrence involve specialized enzymatic processes that form C–C linkages between sugar donors and carbon