New lanostane-type triterpenoids, inonotsutriols D, and E, from Inonotus obliquus

Two new lanostane-type triterpenoids, inonotsutriols D (1) and E (2), were isolated from the sclerotia of Inonotus obliquus (Pers.: Fr.) Pil. (Japanese name: kabanoanatake; Russian name: chaga). Their structures were determined to be lanost-8-ene-3β,22R,24R-triol (1) and lanost-8-ene-3β,22R,24S-triol (2) on the basis of spectral data, including 2D NMR analysis. In addition, major compounds, inotodiol (3), trametenolic acid (4), 3β-hydroxylanosta-8,24-dien-21-al (5), 21-hydroxylanosterol (6), inonotsuoxide A (7) and inonotsuoxide B (8) were identified, and all compounds, except 2, were evaluated for their cancer cell growth inhibitory activity against P388, HL-60, L1210 and KB cell lines.