Unusual phenolic glycosides from Cotoneaster orbicularis

The whole plant of Cotoneaster orbicularis contains the novel di-C-glycosylflavone 4,4'-di-O-beta-glucopyranosyl-vicenin II, or 6.8-di-C-beta-Cellobiosylapigenin, as well as the hitherto unknown natural phenolic glucoside, gentisic acid 2-O-beta-glucopyranoside, or orbicularin. Further phenolics are protucatechuic. anisic, caffeic, p-coumaric acids, catechin, epicatechin. 2-O-alpha-rhamnopyranosylvitexin, vitexin, rutin, isoquercetrin, hyperin and naringenin. All structures were determined by routine methods of analysis and confirmed mostly by H-1- and C-13-NMR. (C) 2000 Elsevier Science Ltd. All rights reserved.