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.

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