Antimalarial, antimycobacterial and cytotoxic limonoids from Chisocheton siamensis.

Five limonoids isolated from the seeds of Chisocheton siamensis were tested for their antimalarial activity against Plasmodium falciparum, antimycobacterial activity against Mycobacterium tuberculosis and cytotoxic activity against NCI-H187 (human small cell lung cancer), KB (oral human epidermal carcinoma) and MCF-7 (breast cancer) cancer cell lines. All limonoids (1-5) showed inhibitory effect against Plasmodium falciparum with IC(50) values ranging from 2.06 to 6.31 microg/ml. Only azadiradione (2) exhibited strong inhibitory effect against Mycobacterium tuberculosis with the MIC of 6.25 microg/ml. Compounds 1-4 also showed cytotoxic activity against NCI-H187, KB and MCF-7 cancer cell lines and dysobinine (1) had the highest activity with IC(50) of 1.67, 3.17 and 2.15 microg/ml, respectively.