The structures and anticancer effects of two sesquiterpene lactones, 1 R,10S,3S,4R-diepoxyguai-5S,6S,7S-11(13)-en-6,12-olide (1) and hanphyllin (2) isolated from the aerial part of Tanacetopsis karataviensis (Kovalevsk.) Kovalevsk were investigated. The compound 1 was isolated for the first time as a natural compound and its structure was investigated by HR-ESI-MS, IR and NMR techniques. The X-ray diffraction analysis was performed to accurately determine the spatial structures of 1 and 2. Furthermore, we evaluated the cytotoxic activity of 1 and 2, and the chloroform fraction which contains both of them. Cytotoxic activity revealed that the effect of the chloroform fraction is stronger in growth inhibition of HeLa (89.7%) and HEp-2 (63.0%) cancer cells than the effect of individual compounds 1 (55.9 and 36.3%), 2 (78.6 and 50.3%) and the reference cisplatin (58.0 and 46.8%) respectively. Moreover, the chloroform fraction is less toxic to the hepatocytes.
Keywords: Tanacetopsis karataviensis (Kovalevsk.) Kovalevsk; X-ray analysis; cytotoxic activity; sesquiterpene lactones.