Chemical Constituents from Inonotus obliquus and Their Biological Activities

Seven new triterpenes, inonotusol A–G (1–7), one new diterpene, inonotusic acid (8), and 22 known compounds were isolated from Inonotus obliquus. Their structures were elucidated on the basis of spectroscopic analysis, including homonuclear and heteronuclear correlation NMR (1H–1H COSY, ROESY, HSQC, and HMBC) experiments. In in vitro assays, compounds 6 and 8–16 showed hepatoprotective effects against d-galactosamine-induced WB-F344 cell damage, with inhibitory effects from 34.4% to 81.2%. Compounds 7, 17, and 18 exhibited selective cytotoxicities against KB, Bel-7402, or A-549 cell lines. Compounds 16 and 17 showed inhibitory effects against protein tyrosine kinases, with IC50 values of 24.6 and 7.7 μM, respectively.