A new benzoin derivative from the medicinal plant Viscum coloratum

Chemical investigation of Viscum coloratum resulted in the isolation of a new benzoin, named 7-O-demethylamycolabenzoyl (1), along with two known isoflavones (2 and 3) and two known flavones (4 and 5). The structure of 1 was elucidated through extensive NMR and HRESIMS analysis and was further confirmed by 13CNMRcalculations. The absolute configuration at the sole chiral center was assigned as R by comparison of its experimental ECD spectrum with that of the analogue amycolabenzoyl (1a). A plausible biosynthetic pathway for 1 is proposed, suggesting its derivation from the co-isolated isoflavone 2. Compound 1 showed weak α-glucosidase inhibitory effects.