Two new bufadienolides from the rhizomes of Helleborus thibetanus Franch

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 5β,14β-dihydroxy-19-oxo-3β-[(α-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.

Graphical abstractFour compounds, including two new bufadienolides named tigencaoside A(1) and tigencaoside B(2) and two known bufadienolides were isolated from the rhizomes of Helleborus thibetanus Franch. Their structures were elucidated on the basis of extensive spectroscopic analysis.Figure optionsDownload full-size imageDownload as PowerPoint slide