Silk protein, sericin, suppresses colon carcinogenesis induced by 1,2-dimethylhydrazine in mice.

Male 5-week old ICR mice were examined for the effect of feeding silk protein, sericin on colon carcinogenesis. In experiment 1, mice were fed the diets supplemented with 1.5% or 3% sericin for five weeks, and given weekly injections of 1,2-dimethylhydrazine (DMH) for the initial three weeks. Supplemental sericin caused a dose-dependent decrease in the development of colonic aberrant crypt foci. In experiment 2, mice were fed the diet supplemented with 3% sericin for 115 days, and given weekly injections of DMH for the initial ten weeks. The incidence and number of colon tumors were suppressed by consumption of sericin. The results suggest a potential usefulness of sericin as a chemopreventive agent for colon carcinogenesis.