Cytotoxic Constituents from the Stem Bark of Chisocheton pentandrus

Eight cytotoxic constituents, consisting of six triterpenoids, cabralealactone (1), cabraleadiol (2), prototiamin A (3), 23-desmethyllimocin B (5), melianodiol (7) and indicalilacol (8) along with one limonoid, neemfruitins A (4) and one protolimonoid, protoxylocarpin G (6), were isolated from the extract of n-hexane of the stembark of Chisocheton pentandrus. The chemical structures were identified on the basis of spectroscopic evidence and compared to previously reported spectra. These isolated compounds appear for the first time in the plant. Compounds 1 - 8 were evaluated for their cytotoxic effect against MCF-7 breast cancer lines in vitro. Among the isolated compounds, melianodiol (7) showed the strongest cytotoxic activity with IC50 values of 16.8 μM.