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 promote rs 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 a nd also exhibited remarkable inhibitory effects on mouse skin tumor promoti on in an in vivo two-stage carcinogenesis test. These data suggest that cer tain diarylheptanoids might be valuable antitumor promoters and/or chemopre ventors. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.