Cytotoxic limonoids from the barks of Chisocheton siamensis.

A phytochemical study of 90% methanol extract of the barks of Chisocheton siamensis afforded three undescribed limonoids, siamensisines A-C (1-3). The structures of the new compounds were elucidated by spectroscopic analysis (NMR, IR, UV, and MS). The isolated limonoids were tested in vitro for cytotoxic activities against 5 pancreatic cell lines. As a result, limonoid 3 exhibited some cytotoxic activities against all the tested tumor cell lines with IC50 values less than 20 μM.