Inhibitory effects of lanostane-type triterpene acids, the components of Poria cocos, on tumor promotion by 12-O-tetradecanoylphorbol-13-acetate in two-stage carcinogenesis in mouse skin.

Pachymic acid, 3-O-acetyl-16 alpha-hydroxytrametenolic acid, and poricoic acid B had been isolated from the sclerotium of Poria cocos Wolf. These compounds showed a strong inhibitory activity against 12-O-tetradecanoylphorbol-13-acetate-induced inflammation in mice. At 0.2 mumol/mouse, these compounds markedly inhibited the promoting effect of 12-O-tetradecanoylphorbol-13-acetate (1 microgram/mouse) on skin tumor formation following initiation with 7,12-dimethylbenz[a]anthracene (50 micrograms/mouse).