The CH2Cl2 soluble part of the leaves of Helianthus tuberosus L. (Compositae) exhibited a potent cytotoxic activity against the cultured human tumor cell lines including A-549, SK-OV-3, SK-MEL-2 XF498 and HCT-15 in vitro. Bioassay-directed fractionati...
The CH2Cl2 soluble part of the leaves of Helianthus tuberosus L. (Compositae) exhibited a potent cytotoxic activity against the cultured human tumor cell lines including A-549, SK-OV-3, SK-MEL-2 XF498 and HCT-15 in vitro. Bioassay-directed fractionation of the CH2CL2 soluble part of this plant led to the isolation of four cytotoxic sesquiterpene lactones having a-methylene-g-lactone ring in the molecule. On the basis of physical and spectral evidences. their structures were characterized as △4.15-isoatripliciolide tiglate (1), △4.15-isoatripliciolide methacrylate (2), budlein A isobutylate (3) and budlein A tiglate (4), The △4.15-isoatripliciolide tiglate (1) showed the most potent cytotoxic activity (0.26 μM<ED50<2.16μM) against all of the cell lines tested.