Cytotoxic limonoids from the bark of Walsura cochinchinensis.

Three new limonoids, walsucochinones A-C (1-3), along with eight known compounds, were isolated from an ethyl acetate extract of the bark of Walsura cochinchinensis. Their structures were determined using spectroscopic techniques, mainly 1-D and 2-D NMR. The ethyl acetate extract showed cytotoxic activity against MCF-7 human breast cancer cells and cytotoxicity of the isolated compounds were evaluated in vitro using the SRB assay. Walsucochinone C (3) exhibited the most active effect with IC₅₀ value of 16.4 ± 0.2 μM.