Abstract
Seven new 15-keto pregnane glycosides, namely Stemmosides E–K, were isolated from
Solenostemma argel. Stemmosides E–J are characterized by the occurrence of an uncommon 14β proton configuration while stemmosides E and F possess in addition a rare enolic function in C-16. On the other hand, stemmosides G–J display an unusual C-17α side chain. Their structures were established by ESI-MS and NMR experiments. Moreover, the effect of these compounds on the VEGF-induced in Kaposi's sarcoma cell proliferation was tested. Results indicated that all the compounds reduced the cell proliferation in a dose dependent manner.