Dietary Quercetin, Immune Functions and Colonic Carcinogenesis in Rats

Abstract

Rats fed 100 mg/kg quercetin (QUE) daily for 7 weeks had significantly enhanced natural killer cell activity compared to their vehicle (VEH)-fed control. In contrast, rats fed 100 mg/kg QUE and treated with the colon carcinogen, azoxymethane had significantly reduced natural killer cell activity compared to their VEH-fed azoxymethane-treated control. There was no significant difference in natural killer cell activity between the two control groups. Antibody production and delayed-type hypersensitivity were not altered by QUE feeding in any treatment group. In vitro exposure of splenic natural killer cells to 1 mM QUE significantly decreased natural killer cell cytotoxicity. Lower QUE concentrations produced a non-significant reduction in natural killer cell activity that was restored to control values at 1×10^-13M QUE. The distribution, multiplicity and total number of colonic preneoplastic lesions, aberrant crypt foci, was not significantly different in the QUE-fed azoxymethane-treated rats when compared to azoxymethane-treated vehicle-fed rats at the conclusion of the 7 week feeding period. We found no correlation between immune function and development of preneoplastic colon lesions in this study.