Three new polymeric isopropenyl benzofurans from Ligularia stenocephala.

Three new polymeric isopropenyl benzofurans, 4-methyl-2,4-bis(5,6-dimethoxy-2-benzofuranyl)-1-pentene, stenocephalin A (1), 4,6-dimethyl-2,4,6-tri(5,6-dimethoxy-2-benzofuranyl)-1-heptene, stenocephalin B (2) and 4,6,8-trimethyl-2,4,6,8-tetra(5,6-dimethoxy-2-benzofuranyl)-1-nonene, stenocephalin C (3), together with seven known compounds (4-10) were isolated from the roots of Ligularia stenocephala. The structures of the new compounds were elucidated on the basis of spectral evidence, especially on 2D NMR. In addition, the cytotoxic activity and the anti-bacterial activity of compounds 2, 3, 5 and 6 were tested.