Quercetin Flavonoid Has In Vivo Antioxidant Properties By Increasing Hepatic Expression Of Gpx And Hepatic Gpx Enzyme Activity In Old Rats

Abstract

BackgroundQuercetin, one of the major flavonoids present in the human diet, has been associated with a wide range of biological properties, including antioxidant, anti‐inflammatory and anticarcinogenic actions. The antioxidant action is considered as the most likely mechanism for the beneficial effects of quercetin. However, little is known on its activity in vivo. Therefore, the present study aimed to investigate the in vivo effects of quercetin on mRNA and activity levels of hepatic GSTa2 in aged rats. This study was carried out on 28 male Wistar albino rats of 24‐months age. Rats were allocated into 2 groups: 1‐Quercetin treated group (14 rats): Received Quercetin (50 mg/kg by gavage for 7 days). 2‐Control group (14 rats): Received 1 ml/kg distilled water by gavage for 7 days.ResultsQuercetin treatment resulted in significant increase in relative hepatic mRNA levels for glutathione peroxidase (GPx) and liver GPx enzyme activity (1.67 ± 0.78 versus 1 ± 0.05, p< 0.01 and 375.92±27.84 versus 242.78 ±19.79 mU/mg protein, p<0.01 respectively). On the other hand, it significantly decreased relative hepatic mRNA levels for Gsta2, hepatic GST enzyme activity and hepatic glutathione concentrations (0.45 ± 0.16 versus 1 ± 0.04, p< 0.01, 127.78±12.9 versus 181.85±17.23 mU/mg protein, p<0.01 and 19.55 ±3.96 versus 23.78 ± 3.28, p<0.01 respectively). No significant difference was found in BMI or in plasma concentration of ox‐LDL between the two groups of aged rats.ConclusionOur results indicate that quercetin flavonoid has in vivo antioxidant properties by increasing hepatic expression of GPx and hepatic GPx enzyme activity in old rats.