[Chemical constituents of flavonoids and their glycosides in Melastoma dodecandrum].

The chemical constituents of 95% ethanol extract of Melastoma dodecandrum were isolated and purified by chromatography on silica gel, Sephadex LH-20, and HPLC, to obtain thirteen compounds eventually. On the basis of their physico-chemical properties and spectroscopic data, these compounds were identified as quercetin (1), quercetin-3-O-β-D-glucopyranoside (2), quercetin-3-O-(6"-O-p-coumaroyl) -β-D-glucopyranoside (3), kaempferol (4), kaempferol-3-O-β-D-glucopyranoside (5), kaempferol-3-O- [2",6"-di-O-(E)-coumaroyl]-β-D-glucopyra-noside (6), luteolin (7), luteolin-7-O-(6"-p-coumaroyl) -β-D-glucopyranoside (8), apigenin (9), apigenin-7-(6"-acetyl-glucopyranoside) (10) , naringenin (11), isovitexin (12), and epicatechin-[8,7-e] -4β-(4-hydroxyphenyl)-3,4-dyhydroxyl-2(3H)-pyranone (13). Eight compounds(3,5,6,8-11 and 13) were obtained from M. dodecandrum for the first time.