Two new bufadienolides from the rhizomes of Helleborus thibetanus Franch
摘要:
Two new bufadienolides, named tigencaoside A(1) and tigencaoside B(2), were isolated from the rhizomes of Helleborus thibetanus Franch., along with two known bufadienolides, hellebrigenin (3) and 5 beta,14 beta-dihydroxy-19-oxo-3 beta-[(alpha-L-rhamnopyranosyl)oxy]bufa-20,22-dienolide (4). Their structures were elucidated on the basis of extensive spectroscopic analysis. Two new compounds were evaluated for their cytotoxic activities against four strains of cultured tumor cells. (C) 2010 Elsevier B.V. All rights reserved.