Unusual phenolic glycosides from Cotoneaster orbicularis

The whole plant of Cotoneaster orbicularis contains the novel di- C-glycosylflavone, 4″,4‴-di- O-β-glucopyranosyl-vicenin II, or 6,8-di- C-β-Cellobiosylapigenin, as well as the hitherto unknown natural phenolic glucoside, gentisic acid 2- O-β-glucopyranoside, or orbicularin. Further phenolics are protocatechuic, anisic, caffeic, p-coumaric acids, catechin, epicatechin, 2″- O-α-rhamnopyranosylvitexin, vitexin, rutin, isoquercetrin, hyperin and naringenin. All structures were determined by routine methods of analysis and confirmed mostly by 1 H - and 13 C -NMR.