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

Abstract

Investigation of the Chinese crude drug 'Xiebai,' the bulbs of Allium chinense G. DON (Liliaceae), led to the isolation of 2 saponins, xiebai- saponin I (laxogenin 3-O-β-xylopyranosyl (1→4)-[α-arabinopyranosyl (1→6)]-β-glucopyranoside) (1) and laxogenin 3-O-α-arabinopyranosyl (1→6)- β-glucopyranoside (2), and the aglycone, laxogenin (3), together with 2 chalcones, isoliquiritigenin (4) and isoliquiritigenin-4-O-glucoside (5), and β-sitosterol glucoside (6). Compounds 15 were tested in vitro for their inhibitory effect on the 12-O-tetradecanoylphorbol-13-acetate (TPA)- stimulated 32Pi-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.