Citrus Flavonoid Nobiletin Suppresses Azoxymethane-Induced Rat Colon Tumorigenesis

We investigated the modulatory effect of citrus nobiletin on colon carcinogenesis initiated with azoxymethane (AOM) in rats. Starting one week after the initiation, rats received the diet mixed with 100 or 500 ppm nobiletin for 34 weeks. The inhibition rates of colonic adenocarcinoma in rats that received 100 or 500 ppm nobiletin after AOM exposure were 18% and 48%, respectively. Also, nobiletin feeding suppressed the prostaglandin E 2 levels and cell proliferation activity, and enhanced apoptosis in colonic adenocarcinomas. These results suggested that citrus nobiletin might be a possible chemopreventive agent against colon cancer development.