The effects of the flavonoids quercetin and genistein on the antioxidant enzymes Cu, Zn superoxide dismutase, glutathione peroxidase, and glutathione reductase in male Sprague-Dawley rats
Governo, Annette Cairns
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Quercetin (QC) and genistein (GS) are phytochemicals found in fruits and vegetables. These compounds may exert protective effects by altering antioxidant enzyme activities. The objective of the study was to examine the effects of QC and GS supplementation on the activities of the antioxidant enzymes glutathione reductase (GR), glutathione peroxidase (GSHPx), and Cu, Zn superoxide dismutase (SOD) in liver, and SOD activity in red blood cells (RBC), as well as the Ferric Reducing Antioxidant Potential (FRAP). Male, weanling Sprague-Dawley rats (n=7-8 group) were fed quercetin at 0.3, 0.6 or 0.9g/100g of diet or genistein at 0.008, 0.012, or 0.02g/100g diet for 14d. GS supplementation significantly increased liver GSHPx activity compared to control (p<0.01). GS did not significantly alter activities of liver SOD and GR, or RBC SOD. QC did not significantly alter antioxidant enzyme activities in liver or RBC. Neither QC nor GS increased the antioxidant capacity of serum. In conclusion, low levels of GS significantly increased liver GSHPx activity, which may contribute to this isoflavone’s protective effects.