Effect of complex polyphenols on colon carcinogenesis

Background: Complex polyphenols and tannins fi om wine (WCPT) are being con sidered increasingly as potential cancer chemopreventive agents, since epid emiological studies suggest that populations consuming a high amount of pol yphenols in the diet may have a lower incidence of some types of cancer. Aim of the study: We studied the effect of WCPT on a series of parameters r elated to colon carcinogenesis in rats. Methods: WCPT were administered to F344 rats at a dose of 14 or 57 mg/kg/d. mixed with the diet. The higher dose is about ten times the exposure to po lyphenols of a moderate drinker of led wine. In rats treated with WCPT, we measured fecal bile acids and long chain fatty acids, colon mucosa cell pro liferation, apoptosis and, after administration of colon carcinogens, the n umber and size of aberrant crypt foci (ACF) and nuclear aberrations. Results: Colon mucosa proliferation was not varied by chronic administratio n (90 d) of WCPT (14 or 57 mg/kg/d). The highest dose of WCPT decreased the number of cells in the colon crypts, but did not increase apoptosis. WCPT (57 mg/kg) administered before or after the administration of azoxymethane (AOM) did not vary the number or multiplicity of ACF in the colon. The numb er of nuclear aberrations (NA) in colon mucosa was studied after administra tion of 1,2-dimethylhydrazine (DMH) and 2-amino-3-methylimidazo (4,5-f)quin oline (IQ), colon-specific carcinogens which require metabolic activation. The effect of DMH and IQ was not varied by pre-feeding WCPT (57 mg/kg) fur 10 d. Similarly, the levels of total, secondary bile acids and long chain f atty acids did not varied significantly in animals fed WCPT for 90 d. Conclusions: WCPT administration does not influence parameters related to c olon carcinogenesis in the rat.