Sesquiterpenoids from Ligularia virgaurea spp. Oligocephala

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