Cytotoxic sesquiterpene coumarins from the roots of heptaptera cilicica

Preliminary 2-day cancer cell screening assays indicated that the dichloromethane extract of the roots of Heptaptera cilicica showed relatively strong cytotoxic activity. Eleven sesquiterpene coumarin ethers with potent and selective cytotoxic activities were isolated from the dichloromethane extract of the roots of H. cilicica. Furthermore, revised spectroscopic data for 14'-acetoxybadrakemone (4) and complete NMR spectroscopic assignments for colladonin (6) and colladin (7) are reported.