Sesquiterpenes with various carbon skeletons from Ligularia virgaurea spp. oligocephala

Two new 8,9-seco-cacalol-type sesquiterpene lactones, ligulolide C (1 and 2) and six known sesquiterpenes, adenostylicle (3 and 4), cacalol (5), 1 -hydroxy-2-(3'-pentenyl)-3,7-dimethylbenzofuran (6), 1 beta, 6 alpha-dihydroxy-4(14)-eudesmene (7) and (+)-oplopanone (8), have been isolated from an extract of the whole plant of Ligularia virgaurea spp. oligocephala. The structures of 1 and 2 were confirmed by spectroscopic methods including 1D and 2D NMR spectra. A discussion of biogenesis of 1 and 2 was described. Cytotoxicity against selected cancer cells human promyelocytic leukemia (HL-60), human ovarian (HO-8910) and human lung epithehial (A-549) of compounds 1-8 were measured in vitro.