• Korean Journal of Pharmacognosy
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• v.43 no.1
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• pp.6-9
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• 2012

The $CH_2Cl_2$ 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. Bioassaydirected fractionation of the $CH_2Cl_2$ soluble part of this plant led to the isolation of four cytotoxic sesquiterpene lactones having ${\alpha}$-methylene-${\gamma}$-lactone ring in the molecule. On the basis of physical and spectral evidences, their structures were characterized as ${\Delta}^{4,15}$-isoatripliciolide tiglate (1), ${\Delta}^{4,15}$-isoatripliciolide methacrylate (2), budlein A isobutylate (3) and budlein A tiglate (4). The ${\Delta}^{4,15}$-isoatripliciolide tiglate (1) showed the most potent cytotoxic activity ($0.26{\mu}M<ED_{50}<2.16{\mu}M$) against all of the cell lines tested.