Stomach carcinogenicity of caffeic acid, sesamol and catechol in rats and mice.

The carcinogenic potential of caffeic acid, sesamol and catechol was examined in male and female F344 rats and B6C3F1 mice, groups of 30 animals being treated with diets containing 2% caffeic acid, 2% sesamol or 0.8% catechol for 104 weeks (rats) or 96 weeks (mice). Histological examination revealed that caffeic acid induced forestomach squamous cell carcinoma in 57% (P less than 0.001 vs. controls) and 50% (P less than 0.001) of male and female rats, respectively, whereas sesamol was associated with squamous cell carcinoma at incidences of 31% (P less than 0.001) in male rats, and 38% (P less than 0.001) and 17% (P less than 0.05) in male and female mice, respectively. Catechol induced glandular stomach adenocarcinomas in 54% (P less than 0.001) and 43% (P less than 0.001) of male and female rats, respectively. The results thus clearly demonstrated that all three antioxidants are carcinogenic in rodent stomach epithelia.