Antiproliferative Triterpenoid Saponins from Leptaulus Citroides Baill. from the Madagascar Rain Forest

Bioassay-guided fractionation of EtOH extracts obtained from the roots and wood of the Madagascan plant Leptaulus citroides Baill. (Cardiopteridaceae) led to the isolation of ethyl esters of three new triterpenoid saponins ( 1 – 3 ) and the known sesquiterpenoid cinnamosmolide ( 4 ). The structures of 1 – 3 were elucidated by extensive 1D and 2D NMR experiments and mass spectrometry. Compounds 1 , 2 , and 4 showed moderate cytotoxicity against the A2780 human ovarian cancer cell line with IC 50 values of 2.8, 10.2 and 2.0 µM, respectively. Graphical Abstract