Structure and cytotoxic evaluation of five 12-oxygenated eremophilanes from Ligularia lingiana

Five new 12-oxygenated eremophilane sesquiterpenoids bearing a B-ring enone system were isolated from Ligularia lingiana S.W. Liu (Asteraceae) collected in China. Compound 5 was a Diels-Alder adduct of 3 alpha-angeloyloxy-7 beta H-8-oxoeremophila-9,11(13)-dien-12-al and the monoterpene, ocimene. Compound I showed cytotoxic activities against HeLa, HL60, Jurkat, and NIH-3T3 cells at IC50 0.0407, 0.440, 0.313, and 3.48 mu M, respectively. (C) 2014...