Saponins Isolated from Allium chinense G. DON and Antitumor-promoting Activities of Isoliquiritigenin and Laxogenin from the Sama 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 1-5 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.