Dose-response assessment of the anti-cancer efficacy of soy isoflavones in dimethylhydrazine-treated rats fed 6% fructooligosaccharide.
- Author:
Hye Young SUNG
1
;
Young Sun CHOI
Author Information
- Publication Type:Original Article
- Keywords: Aberrant crypt foci; cyclooxygenase-2; fructooligosaccharide; soy isoflavone; colon cancer
- MeSH: Aberrant Crypt Foci; Animals; Biological Availability; Colon; Colonic Neoplasms; Cyclooxygenase 2; Diet; Equol; Humans; Hydrogen-Ion Concentration; Isoflavones; Male; Oligosaccharides; Plasma; Rats
- From:Nutrition Research and Practice 2008;2(2):55-61
- CountryRepublic of Korea
- Language:English
- Abstract: We investigated the combinatorial effects of different doses of dietary soy isoflavones (SI) and fructooligosaccharide (FOS) in a rat model of colon cancer. We hypothesized that increased bioavailability of SI metabolites due to dietary FOS may increase production of bioactive equol and affect colon carcinogenesis in a dose-dependent manner. Sprague-Dawley male rats were injected with 12-dimethylhydrazine (DMH) and were provided experimental diets that contained 0, 10, 50, 150, or 500 mg SI per kg of diet and 6% FOS for 12 weeks. The number of aberrant crypt foci (ACF) and the expression of cyclooxygenase-2 (COX-2) in colonic tissues were significantly decreased in the 6% FOS-fed groups compared to the control group. Gut transit time and fecal pH were significantly lower, and fecal concentrations of bifidobacteria were increased with 6% FOS. However, dietary SI supplementation in combination with 6% dietary FOS did not affect ACF formation or COX-2 expression. Plasma equol concentrations were dose-dependently increased by supplementation of SI up to 500 mg/kg of diet. In conclusion, SI supplementation up to 500 mg/kg of diet appeared to have no additive beneficial effects in rats with chemically-induced colon cancer that were fed 6% FOS, although plasma equol was dose-dependently increased.
