Three new lanostane triterpenoids from Inonotus obliquus

Three new lanostane-type triterpenoids, inonotsulides A, B, and C (1-3, resp.) were isolated from the sclerotia of Inonotus obliquus (PERS.: Fr.) (Japanese name: Kabanoanatake; Russian name: Chaga). Their structures were determined to be (20R,24S)-3 beta,25-dihydroxylanost-8-en-20,24-olide (1), (20R,24R)-3 beta,25-dihydroxylanost-8-en-20,24-olide (2), and (20R,24S)-3 beta,25-dihydroxylanosta-7,9(11)-dien-20,24-olide (3) on the basis of chemical transformation, NMR spectroscopy including ID and 2D (H-1,H-1-COSY, NOESY, HMQC, HMBC), EI-MS, and single-crystal X-ray analysis.