New flavonol glycosides from Barbeya oleoides Schweinfurth

Three new flavonol glycosides, 3',5' dimethoxymyricetin-4 `'-O-alpha-L-rhamnopyranosyl (1-4) beta-D-glucopyranoside (1), 3'-methoxyquercetin-4 `'-O-alpha-L-rhamnopyranosyl (1-4) beta-D-glucopyranoside (2) and 3'-methoxyqurecetin-6 `'-O-alpha-L-rhamnopyranosyl (1-6) beta-D-glucopyranoside (3), have been isolated from the aerial part of Barbeya oleoides Schweinf., along with twelve known compounds, uvaol (4), ursolic acid (5), corosolic acid (6), arjunolic acid (7), beta-sitosterol-3-O-beta-D-glucoside (8), (+)-catechin (9), (-)-epicate-chin (10), isorhamnetin-4'-O-glucoside (11), arjunglucoside I (12), D-(-)-bornesitol (13), gallocatechin (14) and epigallocatechin (15). Compounds 4-15 were isolated for the first time from Barbeyaceae. Structure elucidation of compounds 1-3 was based on MS and NMR data. The ethyl acetate extract of the stems as well as compounds 5, 6, 14 and 15 showed significant antimicrobial activity, while the ethanol extracts of leaves, stems and compounds 4, 7, 8, 13-15 have dose-dependent spasmolytic action. (C) 2011 Elsevier Ltd. All rights reserved.