Sesquiterpene Coumarin Ethers and Phenylpropanoids from the Roots of Ferula drudeana, the Putative Anatolian Ecotype of the Silphion Plant.

Four new sesquiterpene coumarin ethers (1-4) and a new phenylpropanoid compound (5) were isolated from a hexane extract of the roots of Ferula drudeana, the putative Anatolian ecotype of the silphion plant, in addition to nineteen previously described sesquiterpene coumarins (6-24) and four known phenylpropanoid derivatives (25-28). The structures of these compounds were elucidated by extensive spectroscopic analysis and computational studies. The cytotoxic activities of all isolated compounds were evaluated on renal, malignant pleural mesothelioma (MPM) and colon cancer cell lines. While 11 sesquiterpene coumarin derivatives showed strong-to-moderate cytotoxic activity against the UO31 renal cancer cell line, 13 compounds showed strong cytotoxic activity against the MPM cell line, and four sesquiterpene coumarin derivatives displayed moderate cytotoxic activity against the colon cancer cell line.