Chemical constituents from Inonotus obliquus and their antitumor activities.

Four new lanostane-type triterpenes (inonotusanes D-G, 1-4), including a 24,25,26,27-tetranorlanostane, together with 11 known compounds (5-15), including 7 lanostane derivatives, 2 steroids and 2 aromatic compounds, were isolated from the sclerotia of Inonotus obliquus. Their structures were elucidated by 1D and 2D NMR spectroscopy and HRMS. To our knowledge, 1 is the first 24,25,26,27-tetranorlanostane-type triterpenoid from fungus, and this is the first time that 31-member lanostane-type triterpenes, 5 and 6, have been isolated from the sclerotia of I.