Poricoic acid B shows inhibitory activity against TPA-induced ear inflammatory oedema, it also shows potent inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA)

These two, and eight other known compounds isolated from the sclerotium, Poricoic acid B (3), poricoic acid A (4), tumulosic acid (5), dehydrotumulosic acid (6), 3-epidehydrotumulosic acid (7), polyporenic acid C (8), 25-hydroxy-3-epidehydrotumulosic acid (9), and dehydroabietic acid methyl ester (10), showed potent inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Evaluation of the cytotoxicity of compounds 1 and 4 against human cancer cell lines revealed that 1 was significantly cytotoxic to leukemia HL-60 cells [GI(50) (concentration that yields 50% growth) value 39.3 nM], although it showed only moderate cytotoxicity to the other cells. Compound 4 exhibited moderate cytotoxicity to all of the cancer cell lines tested.