Two new cytotoxic constituents from the Clausena lansium (Lour.) Skeels

- Compounds of the stems of Clausena lansium were studied. Among them, there were two new compounds with four known compounds.
- Up to now there are no reports on the new compounds and the cytotoxicity of the compounds against three tumor cell lines.
- The results of the cytotoxicity were discussed.

Two new compounds 6-methoxy-9H-carbazole-3-carboxylic acid (1) and 9-[3-methyl-4-(4-methyl-5-oxo-tetrapydro-furan-2-yl)-but-2-enyloxy]-furo[3,2-g]chromen-7-one (5) along with four known compounds clausine D (2), claulansines J (3), O-demethylmurrayanine (4) and pabularinone (6) were isolated from the Clausena lansium. The chemical structures of the new compound were elucidated by 1D and 2D NMR as well as HR-ESIMS spectral analysis. All the compounds isolated were evaluated for cytotoxic effects against human breast cancer (MCF-7), non-small lung carcinoma (H1299) and liver cancer (SMMC-7721). Compounds 2 and 4 exhibited strong cytotoxicity against MCF-7 and SMMC-7721 with IC50values in the range 2.63-7.59 μg/ml, and Compounds 1 and 5 showed moderate cytotoxicity against MCF-7, H1299 and SMMC-7721 tumor cell lines.