Two New Sesquiterpenoids from the Root of Strophanthus divaricatus

Two new sesquiterpenoids, strophanthoids A and B (1and 2), along with seven known cardiac glycosides were isolated from the roots of Strophanthus divaricatus. Their structures were elucidated on the basis of extensive analyses by IR, HR-ESI-MS, NMR, and single-crystal X-ray diffraction. And the new compounds were tested cytotoxic activities on the tumor cells SK-MEL-110 and SK-MEL-28.