Saponins isolated from Allium chinense G. DON and antitumor-promoting activities of isoliquiritigenin and laxogenin from the same drug

Investigation of the Chinese crude drug "Xiebai," the bulbs of Allium chine nse G. DON (Liliaceae), led to the isolation of 2 saponins, xiebai-saponin I (laxogenin 3-O-beta-xylopyranosyl (1-->4)-[alpha-arabinopyranosl (1-->6)] -beta-glucopyranoside) (1) and laxogenin 3-O-alpha-arabinopyranosyl (1-->6) -beta-glucopyranoside (2), and the aglycone, laxogenin (3), together with 2 chalcones. isoliquiritigenin (4) and isoliquiritigenin-4-O-glucoside (5), and beta-sitosterol glucoside (6), Compounds 1-5 were tested in vitro for t heir inhibitory effect on the 12-O-tetradecanoylphorbol-13-acetate (TPA)-st imulated (32)Pi-incorporation into phospholipids of HeLa cells. In addition to this, laxogenin (3) was proven to have an antitumor-promoting activity in a two-stage lung carcinogenesis experiment.