Short- and long-term exposure to low levels of pesticide and flavonoid mixtures modify endogenous antioxidants in tissues of rats
The objective of this study was to determine if interaction between phytochemical mixtures and low level exposure to pesticides would modify tissue endogenous antioxidants in rats. Two experiments were conducted using dietary flavonoid (F) and oral pesticide (P) mixtures (FM, PM) on changes in the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and glutathione concentrations (GSH) in male Sprague Dawley rats (150–175 g) fed for 2 or 4 weeks the AIN 93M diet with or without equal amounts of quercetin, rutin, catechin (FM) at 1.0 mM or 5 mM/kg diet, and with/without PM fed orally at 0.1 mL/d/5d/wk (PM = chlorpyrifos, endosulfan, thiram at 25% LD50 in oil). Our data indicate that (compared to corresponding Control groups): (i) While, 2 weeks of feeding reduced liver and small intestinal mucosal (IM) SOD activity in the PFM1 (PM+FM1) group, 4 weeks of feeding increased only liver SOD activity in PM, FM1, FM5 and PFM1 and PFM5 groups; (ii) Liver and IM GSH levels increased in PFM groups after 2 or 4 weeks of exposure; plasma GSH increased in the groups fed FM5 with or without PM; (iii) Liver GPX activity declined in both 2 and 4 week experiments in the FM and PFM groups, respectively. These data suggests that metabolic interaction between FM and PM, and duration of exposure, can modify endogenous antioxidants. Data also underscore the prooxidant properties of flavonoids.