Triterpene Acids from Poria cocos and Their Anti-Tumor-Promoting Effects

The structures of six new lanostane-type triterpene acids isolated from the epidermis of the sclerotia of Poria cocos were established to be 15α-hydroxydehydrotumulosic acid (5), 16α,25-dihydroxydehydroeburicoic acid (9), 5α,8α-peroxydehydrotumulosic acid (10), 25-hydroxyporicoic acid H (11), 16-deoxyporicoic acid B (12), and poricoic acid CM (16) on the basis of spectroscopic methods. On evaluation of these six and 11 other known triterpene acids isolated from the sclerotium, 1−4, 6−8, 13−15, and 17, against the Epstein−Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells, all of the compounds except for 1, 3, 4, and 8 exhibited inhibitory effects with IC50 values of 195−340 mol ratio/32 pmol TPA. Compound 12 and poricoic acid C (13) exhibited inhibitory effects on skin tumor promotion in an in vivo two-stage carcinogenesis test using 7,12-dimethylbenz[a]anthracene (DMBA) as an initiator and TPA as a promoter.