Phytochemical constituents of Thesium chinense TURCZ and their cytotoxic activities in vitro

Column chromatographic separation of the MeOH extract from the aerial parts of Thesium chinense TURCZ led to the isolation of two norsesquiterpenes (1 - 2), two phenylpropanes (3 - 4) and four flavonoids (5 - 8). Their structures were determined by spectroscopic means to be 5,6-epoxy-3-hydroxy-7-megastigmen-9-ene (1), (-)-loliolide (2), methyl-p-hydroxycinnamate (3), methyl caffeate (4), kaempferol (5), kaempferol-3-O-β-D-glucopyranoside (6), kaepmferol-3,7-di-O-β-D-glucopyranoside (7) and kaempferol-3-O-β-D-glucopyranoside-6"- (3-hydroxy-3-methylglutarate) (8). Compounds 1 - 4, 7 and 8 were first isolated from this source. The isolated compounds were evaluated for their cytotoxicty in vitro using the sulforhodamin B bioassay (SRB).