Cytotoxic limonoids from the twigs of Chisocheton paniculatus.

A chemical study on 80% methanol extract of the twigs of Chisocheton paniculatus led to the isolation of two novel limonoids, paniculatusines A and B (1 and 2). The structures of the new compounds were elucidated by spectral methods such as 1D and 2D (HMQC, and HMBC) NMR spectroscopy, as well as high resolution mass spectrometry. The isolated limonoids were tested in vitro for cytotoxic activities against 5 hepatocellular carcinoma cell lines (SMMC-7721, Bel-7402, MHCC97, HepG2, and Hep3B). Consequently, limonoid 1 exhibited some cytotoxic activities against all the tested tumor cell lines with IC50 values less than 20 μM.