Lack of tumor promoting activity of capsaicin, a principal pungent ingredient of red pepper, in mouse skin carcinogenesis

Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) is the major pungent pri nciple of hot peppers of the genus Capsicum. There have been numerous inves tigations to evaluate the effects of capsaicin on experimental carcinogenes is and mutagenesis, bur the results are discordant. In the present study, w e have assessed the tumor promoting potential of capsaicin using a two stag e mouse skin carcinogenesis model. Repeated applications of capsaicin (10 m u mol) onto the shaven back of female ICR mice following a single-initiatio n dose of 7,12-dimethylbenz[alpha]anthracene did not cause any significant increase- in papilloma formation and abnormal hyperplastic or inflammatory skin lesions, compared with the solvent control Furthermore, the topical ap plication of capsaicin did not induce the epidermal ornithine decarboxylase activity, suggesting that it lacks tumor-promotional activity. On the cont rary, the compound ameliorated the mouse skin carcinogenesis wizen given si multaneously with the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate.