Novel modified furanoeremophilane-type sesquiterpenes and benzofuran derivatives from Ligularia veitchiana

Three new compounds, 2-acetyl-5-isopentenyl-6-methylbenzofuran (1), 1,3-dimethoxy-4,6-dimethylnaphthofuran (2), and 3,4,5-trimethoxycinnamyl angelic acid ester (3), along with 13 known compounds were isolated from the roots of Ligularia veitchiana, which are commonly used as a folk medicine and food supplement in China. Their structures were elucidated by spectroscopic techniques. Biological screening studies indicated that compound 2 displayed a moderate activity against Staphylococcus aureus, which may be due to the existence of a modified eremophilane skeleton, whilst compounds 11, 12 and 15 exhibited potent activity against HL-60 and HeLa cell lines.