Antitumor activities of dammarane triterpene saponins from Bacopa monniera

Bioassay-guided methods were used to test the antitumor activity of methanol extract of the whole plant of Bacopa monniera (L.) Wettst. and four different fractions (petroleum ether, CHCl(3), EtOAc, and n-BuOH fractions) of the methanol extract. Among the five crude samples, n-BuOH fraction was noted to have the highest antitumor activity. The dammarane triterpene saponins isolated from n-BuOH fraction, bacopaside E (1) and bacopaside VII (3), had potential antitumor effect. 1 and 3 showed cytotoxicity of all the tested human tumor cell lines MDA-MB-231, SHG-44, HCT-8, A-549 and PC-3M in MTT assay in vitro, and showed 90.52 % and 84.13 % inhibition in mouse implanted with sarcoma S180 in vivo at the concentration of 50 micromol/kg, respectively. The remaining two compounds, bacopaside II (2) and bacopasaponin C (4) were found to be much less potent compared with 1 and 3. 1 and 3 significantly inhibited human breast cancer cell line MDA-MB-231 adhesion, migration and Matrigel invasion in vitro at the concentration of 50 micromol/L. Since no antitumor activities about the monomers from Bacopa monniera (L.) Wettst. have been reported, these results indicate that the mechanism of action of 1 and 3 needs further study.