Inhibition of experimental carcinogenesis by painting with garlic extract.

The inhibitory effect of topical garlic extract on 7,12-dimethylbenz[a]anthracene (DMBA)-induced oral carcinogenesis in Syrian hamsters was studied to define the local anticarcinogenicity of garlic. Two other chemicals, benzo[a]pyrene (BP) and 5-nitroso-2,4,6-triaminopyrimidine (NTP), were also testing materials. All chemicals were applied topically to the cheek pouches of hamsters. The tumorigenesis and architecture of blood vessels on pouch mucosa were examined periodically. The amount of DNA synthesis and gamma-glutamyl transpeptidase activity of the pouch mucosa was detected when the animals were killed. The anticarcinogenicity of garlic and other chemicals was determined by comparing the data obtained from all the examinations with each other and with those shown in the control animals. The apparent local inhibitory effect of garlic on DMBA-induced carcinogenesis was demonstrated, which was even stronger than those of BP and NTP. It suggests that garlic could be developed as a potential chemopreventive agent for oral cancer. This study also disclosed that the examination parameters used were reliable and reproducible. Therefore, they might be utilized for screening the anticarcinogenicity of materials or for early diagnosis of carcinogenesis. The animal model could also be adopted appropriately in evaluating the inhibitory effect of other materials on experimental carcinogenesis because of its comparability.