New cytotoxic triterpene acids from aboveground parts of Manihot esculenta from the Suriname rainforest.

Two novel triterpene acids, esculentoic acid A ( 1) and B ( 2) as well as the seven known compounds 3 - 9 were isolated from an EtOAc extract of leaves, stems, and twigs of Manihot esculenta by bioassay-guided fractionation for cytotoxic activity. The structures of the two new compounds were established as 3alpha-hydroxytaraxer-14-en-29-oic acid ( 1) and 3-oxotaraxer-14-en-29-oic acid ( 2) on the basis of 1D and 2D NMR spectroscopic data interpretation and chemical conversions. The two new compounds 1 and 2 showed moderate cytotoxicity against the A2780 human ovarian cancer cell line.