Cytotoxic cucurbitane-type triterpenoids from Elaeocarpus hainanensis.

Bioassay-guided fractionation of the crude extract of Elaeocarpus hainanensis (Elaeocarpaceae), using the proliferation of non-small cell lung cancer A549/ATCC and human hepatocellular carcinoma BEL-7402 cells as a monitor, led to the isolation of ten cucurbitane-type triterpenoids, including three new compounds (1-3) and seven known compounds (4-10). Their structures were determined on the basis of spectroscopic analyses, chemical methods, and comparison with spectroscopic data in literature. The two known compounds, cucurbitacins D (5) and I (10) were found to exhibit the strongest cytotoxicity against A549/ATCC and BEL-7402 cells in vitro with IC50 values of less than 1 microM.