Antibacterial lanostane triterpenoids from Ganoderma tsugae

A phytochemical investigation on the 80% EtOH extract of the fruiting bodies of Ganoderma tsugae resulted into the isolation of two previously undescribed lanostane triterpenoids, 7,11-dioxo-3 beta-acetyloxy-26,27-dihydroxy-lanosta-8,24-diene (1) and 7,20-dioxo-3 beta-acetyloxy-11 beta,15 alpha-dihydroxy-22,23,24,25,26,27-hexanorlanosta-8-ene (2), togeher with one known lanostane triterpenoid ganodermanontriol (3). Structural elucidation of all the compounds were performed by spectral methods such as 1D and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy. All the triterpenoids were in vitro evaluated for their antibacterial activities against six pathogenic microorganisms. Compound 3 exhibited some activities against three Gram positive bacteria with MIC values less than 30 mu g/ml.