Antitumor-promoting effects of cyclic diarylheptanoids on Epstein–Barr virus activation and two-stage mouse skin carcinogenesis

Eleven cyclic diarylheptanoids were screened as potential antitumor promoters by examining the ability of the compounds to inhibit Epstein–Barr virus early antigen activation (induced by 12- O-tetradecanoylphorbol-13-acetate) in Raji cells. 13-Oxomyricanol and myricanone showed the highest activity and also exhibited remarkable inhibitory effects on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. These data suggest that certain diarylheptanoids might be valuable antitumor promoters and/or chemopreventors.