title: Cytotoxic sesquiterpene lactones from the root of Saussurea lappa.
abstract: Bioassay-directed fractionation of Saussurea lappa led to the isolation of a novel lappadilactone (1) and seven sesquiterpene lactones (2-8) as cytotoxic principles against selected human cancer cell lines. Lappadilactone (1), dehydrocostuslactone (2), and costunolide (5) exhibited the most potent cytotoxicity with CD50 values in the range 1.6-3.5 microg/mL in dose- and time-dependent manners. The cytotoxicities were not specific and showed similar activities against HepG2, OVCAR-3 and HeLa cell lines. The structure-activity relationship showed that the alpha-methylene-gamma-lactone moiety is necessary for cytotoxicity, and activity is reduced with the presence of a hydroxyl group. In addition, seven noncytotoxic compounds (9-15) were also isolated, including two novel sesquiterpenes, a guaianolide-type with a C17 skeleton, lappalone (13), and 1beta,6alpha-dihydroxycostic acid ethyl ester (14). The structures of the new compounds were elucidated from spectroscopic and/or X-ray data interpretations. Some representative compounds were also tested for antibacterial activity; however, only marginal activities were observed. Therefore, compounds 1-8 are potential cytotoxic agents but without significant antibacterial effect.
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D006528:Carcinoma, Hepatocellular; D018360:Crystallography, X-Ray; D004354:Drug Screening Assays, Antitumor; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D005260:Female; D006367:HeLa Cells / Q000187:drug effects; D006801:Humans; D007783:Lactones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010051:Ovarian Neoplasms; D018517:Plant Roots / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D030441:Saussurea / Q000737:chemistry*; D012717:Sesquiterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D004365:Drugs, Chinese Herbal; D007783:Lactones; D012717:Sesquiterpenes; C481580:lappadilactone