Cytotoxic constituents of Psoralea corylifolia.

A coumestan derivative, psoralidin (1) was found to be a cytotoxic principle of the seeds of Psoralea corylifolia L. (Leguminosae) with the IC50 values of 0.3 and 0.4 microg/ml against the HT-29 (colon) and MCF-7 (breast) human cancer cell lines, respectively. A coumarin, angelicin (2) was also isolated as a marginally cytotoxic agent along with an inactive compound, psoralen (3) from the plant. The isolates 1-3 were not active against the A541 (lung) and HepG2 (liver hepatoma) cancer cell lines.