New lanostanoids of Ganoderma tsugae

Three new compounds, (24R,S)-3 alpha-acetoxy-24-hydroxy-5 alpha-lanosta-8,2 5dien-21-oic acid, named tsugaric acid C (1); 3 alpha-acetoxy-5 alpha-lanos ta-8,24-diene-21-O-beta-xyloside, named tsugarioside B (2); and 3 alpha-ace toxy-(Z)-24-methyl-5 alpha-lanosta-8,23,25-trien-21-oic acid ester beta-D-x yloside, named tsugarioside C (3), and a mixture of two known steroids were isolated from the fruit bodies of Ganoderma tsugae. The structures of 1-3 were determined by spectral and chemical methods. The cytotoxic activity of the lanostanoid constituents of this fungus was evaluated against several different cancer cell Lines.