Sesquiterpenoids from Ligularia virgaurea spp. oligocephala

Four novel eremophilane-type sesquiterpene lactones, 6 beta,10 alpha-dihydroxy-l-oxoeremophila-7(11),8(9)-dien-12,8-olide (1), 6 beta-acetyl-2-oxoeremophila-1(10),7(11),8(9)-trien-12,8-olide(2),60,8-diacetyl-2-oxoeremophila-1(10),7(11)-dien-12,8-olide(3),dimeric eremophilane ligulolide B (5), and known sesquiterpenoid, 6 beta,8 alpha-diacetyleremophila-1(10),7(11)-dien-12,8-olide (4), were isolated from an extract of the whole plant of Ligularia virgaurea spp. oligocephala. The structure of 1 was confirmed by NMR spectra and single crystal X-ray crystallography investigation, as well as 2, 3, and 5 were elucidated by spectroscopic methods including 1D and 2D NMR spectra. A discussion of biogenesis of 5 was described. Cytotoxicities of compound 1 were measured in vitro against selected cancer cells human promyelocytic leukemia (HL-60), human ovarian (HO-8910) and human lung epithehial (A-549). (c) 2005 Elsevier Ltd. All rights reserved.