New cytotoxic cucurbitacins from the pericarps of Trichosanthes tricuspidata fruits

An extract of the fruits of Trichosanthes tricuspidata collected in North Vietnam was found cytotoxic in KB cells. A bioassay-guided fractionation led to the isolation of a series of cucurbitacins of which two are new: tricuspidatin and 2-O-glueocucurbitacin J. Their isolation and structure determination are described.