Two new steroidal saponins from the roots of Cynanchum limprichtii

As a part of our continuing research for bioactive constituents from Cynanchum limprichtii Schltr., two new C₂₁ steroidal glycosides limproside A (1) and limproside B (2) were isolated from the roots of Cynanchum limprichtii. Their structures were elucidated on the basis of 1D- and 2D-NMR spectroscopic data as well as HR-ESI-MS analysis. The cytotoxicity of two compounds against two selected human cancer cell lines was assayed.