Sesquiterpene lactones from Cyathocline purpurea

Cyathocline purpurea (Buch-Ham ex D Don) O Ktze is a folk drug used to treat inflammations and pulmonary tuberculosis in Yunnan Province. Cytotoxicity screening of extracts and its fractions from C. purpurea was carried out by L1210 cell. Isolation of chemical constituents by column chromatography was undertaken in step with cytotoxicity test. The structures of constituents were identified by spectroscopic and chemical methods. The chloroform and ethyl acetate extracts possess cytotoxic activity with IC50's being 3.5 and 2.8 mu g/mL, respectively. Three sesquiterpene lactones were established as Santamarin (compound 1), 9,beta-acetoxycostunolide (compound 2) and 9,6-acetoxypathenolide (compound 3). Their IC50 were 0.41, 0.89, 0.59 mu g/mL by L1210 cell respectively. The three constituents were obtained for the first time from this plant. They are all anticancer active constituents. The last one is a new compound.