Antiproliferative Cardenolide Glycosides of Elaeodendron alluaudianum from the Madagascar Rainforest

Abstract Bioassay-guided fractionation of an ethanol extract of a Madagascar collection of Elaeodendron alluaudianum led to the isolation of two new cardenolide glycosides ( 1 and 2 ). The 1 H and 13 C NMR spectra of both compounds were fully assigned using a combination of 2D NMR experiments, including 1 H– 1 H COSY, HSQC, HMBC, and ROESY sequences. Both compounds 1 and 2 were tested against the A2780 human ovarian cancer cell line and the U937 human histiocytic lymphoma cell line assays, and showed significant antiproliferative activity with IC 50 values of 0.12 and 0.07 μM against the A2780 human ovarian cancer cell line, and 0.15 and 0.08 μM against the U937 human histiocytic lymphoma cell line, respectively.