Cytotoxic oleanane triterpenoids from the rhizomes of Astilbe chinensis (Maxim.) Franch. et Savat.

Bioassay-guided fractionation of the rhizomes of Astilbe chinensis afforded four cytotoxic pentacyclic triterpenoids, 3beta-hydroxy-olean-12-en-27-oic acid (1), 3beta,6beta-dihydroxy-olean-12-en-27-oic acid (2), 3beta-acetoxy-olean-12-en-27-oic acid (3), and 3beta-hydroxy-urs-12-en-27-oic acid (4). The isolation and purification of these compounds was conducted with the application of column chromatography. Their structures were elucidated on the basis of chemical and spectral evidence. 2D NMR techniques including 1H-1H COSY, HMQC, HMBC spectra and HREIMS were extensively applied to establish the structures. Compounds 1-4 showed cytotoxic activities against HO-8910, Hela and HL60 in vitro; moreover, compound 1 induced apoptotic cell death of the HO-8910 in a dose-dependent manner, ranging from 2.5 to 40.0 microg/ml. The presence of these active compounds may be responsible, at least in part, for the antineoplastic action of the traditional crude drug Rhizoma Astilbe chinensis.