DIETARY QUERCETIN AND RUTIN - INHIBITORS OF EXPERIMENTAL COLONIC NEOPLASIA

the phenolic flavonoids quercetin (QU) and rutin (RU) found in the outer leaves of vegetables and fruits were examined as modifiers of an experimental model of colon cancer. CF1 mice were fed an AIN-76A diet to which was added various levels of QU or RU. Acute studies revealed that, in control mice, QU and RU had no effect on colonic epithelial cell proliferation but 2% QU and 4% RU significantly reduced azoxymethanol (AOM) induced hyperproliferation of these cells. The same doses also significantly inhibited the development of focal areas of dysplasia (FADs). Compared with controls, 2% QU for 50 weeks significantly depressed colon tumor incidence while both 2% QU and 4% RU suppressed tumor multiplicity. Thus, under conditions of low dietary fat intake, these flavonoids have considerable activity to suppress the hyperproliferation of colonic epithelial cells, thereby reducing FADs and ultimately colon tumor incidence.