Terpenoids with alpha-glucosidase inhibitory activity from the submerged culture of Inonotus obliquus

Abstract Lanostane-type triterpenoids, inotolactones A and B, a drimane-type sesquiterpenoid, inotolactone C, and five known terpenoids 6 β -hydroxy- trans -dihydroconfertifolin, inotodiol, 3 β ,22-dihydroxyanosta-7,9(11),24-triene, 3 β -hydroxycinnamolide, and 17-hydroxy- ent -atisan-19-oic acid, were isolated from the submerged culture of chaga mushroom, Inonotus obliquus . Their structures were characterized by spectroscopic methods, including MS and NMR (1D and 2D) spectroscopic techniques. Inotolactones A and B, examples of lanostane-type triterpenoids bearing α , β -dimethyl, α , β -unsaturated δ -lactone side chains, exhibited more potent alpha-glucosidase inhibitory activities than the positive control acarbose. This finding might be related to the anti-hyperglycemic properties of the fungus and to its popular role as a diabetes treatment. In addition, a drimane-type sesquiterpenoid and an atisane-type diterpenoid were isolated from I. obliquus .