The chemical constituents from the stems and leaves of Clausena emarginata were separated and purified by column chromatographies on silica gel,ODS,Sephadex LH-20,and PR-HPLC. The structures of the isolated compounds were identified on the basis of physicochemical properties and spectroscopic analysis,as well as comparisons with the data reported in the literature. Sixteen compounds were isolated from the 90% ethanol extract of the stems and leaves of C. emarginata,which were identified as siamenol( 1),murrastanine A( 2),3-formyl-1,6-dimethoxycarbazole( 3),3-methoxymethylcarbazole( 4),3-methylcarbazole( 5),murrayafoline A( 6),3-formylcarbazole( 7),3-formyl-1-hydroxycarbazole( 8),3-formyl-6-methoxycarbazole( 9),murrayanine( 10),murrayacine( 11),girinimbine( 12),nordentatin( 13),chalepin( 14),8-hydroxy-6-methoxy-3-pentylisocoumarin( 15) and ethyl orsellinate( 16). Compounds 1-4,14-16 were isolated from C. emarginata for the first time. Among them,compounds 1,2,15 and 16 were isolated from the genus Clausena for the first time. All isolated compounds were evaluated for their cytotoxic activities against five human cancer cell lines: HL-60,SMMC-7721,A-549,MCF-7 and SW480 in vitro. Compounds 12 and 14 showed significant inhibitory effects against various human cancer cell lines with IC_(50) values comparable to those of doxorubicin.
Keywords: Clausena emarginata; Rutaceae; chemical consituents; cytotoxic activities.