cytotoxic flavonoid glycosides from rapistrum rugosum l.

five flavonoid glycosides were isolated from the n-butanol soluble fraction of the ethanolic extract of rapistrum rugosum and their structures were assigned from 1h- and 13c-nmr spectra (dept) with 2d nmr as quercetin-3-o-α-l-rhamnopyranoside (1), quercetin-3-o-β-d-xyloside (2), quercetin, 3-o-α-l-arabinopyranoside,7-o-α-l-rhamnopyranoside (3), kaempferol 3-o-α-l-arabinopyranoside, 7-o-α-l-rhamnopyranoside (4) and rutin (5). the srb cytotoxic assay was used to investigate the antitumor activities of n-butanol extract, compound 3 and its hexaacetate 3a, for the first time. compounds 3 and 3a showed cytotoxic activity against the human cancer cell line, namely, hepg2 (hepatocellular carcinoma cell line) with ic50 (concentration of compound required to reduce cell survival by 50%) 0.86 µg/ml and 3.50 µg/ml, respectively. these results proved that compound 3, the major flavonoid of the n-butanol soluble fraction, has significant cytotoxic activity compared with the standard antitumor drug doxorubicin (0.60 µg/ml).