Anticarcinogenic Effect of Corn Tortilla Against 1,2-Dimethylhydrazine (DMH)-Induced Colon Carcinogenesis in Sprague-Dawley Rats

Mexico has the highest per capita consumption of corn in the world, which is consumed mainly as tortilla. However, only a few in vivo studies have demonstrated the anticarcinogenic potential of some maize components against colon cancer, but not as a whole food product. Therefore, our objective was to evaluate the protective effect of corn tortillas against the development of colon cancer. First, blue, red, yellow and white corn grains were lime-cooked and processed to elaborate tortillas. Then, tortillas were administered into the diet (27 % w/w) to male Sprague-Dawley rats induced with the colon carcinogen 1,2-dimethylhydrazine (DMH). Our results indicated that consumption of tortillas, particularly from white and blue corns, significantly decreased adenocarcinoma incidence (up to 77.5 %) and mean number compared to DMH-treated animals. In addition, an inhibition of beta-glucuronidase activity, and induction of detoxifying enzymes in liver and colon, as well as a decrease in the expression of the two most important proliferative proteins (K-ras and beta-catenin) involved in colon carcinogenesis, were also observed. These results highlight some of the molecular mechanisms related to the chemopreventive effect of tortillas, thus indicating that corn products retain their biological properties even after nixtamalization and tortilla processing.