Protective effect of quercetin on homocysteine induced oxidative stress

Hyperhomocysteinemia takes place, due to increase in plasma level of homocysteine derived from the metabolism of methionine. Due to hyperhomocysteinemia-induced oxidative stress, reactive oxygen species which initiate lipid peroxidation and membrane demolitions occur. In human body, there are antioxidant defence system which might potentiate the toxic effects of reactive oxygen species and antioxidants repairing injures. Flavonoids which are produced by various plants can protect biological membranes against free radical-induced oxidative damageThe aim of present study is to evaluate whether the quercetin treatment could have a protective effect against oxidative stress-induced by hyperhomocysteinemia in rats or not.For this purpose, thirty two male Sprague-Dawley rats(adult) were divided four groups: 1. Control group (C); received saline, as intraperitonal (1,5 ml/day). 2. Quercetin group (Q); received quercetin (50 mg/kg/day) as intraperitonal and saline (0,25 ml/day). 3. Homocysteine group (Hcy); received homocysteine (1 mg/kg/day) and saline (1,25 ml/day). 4. Quercetin + Homocysteine group (Q+Hcy); Quercetin (50 mg/kg/day) was introduced 1 h before Hcy administration (1 mg/kg). Quercetin (1 g) was suspened in 100 ml of salinePlasma malondialdehide (MDA), plasma carbonyl, erythrocyte glutation (GSH), plasma sulfhydril (SH), erythrocyte catalaz and erythrocyte superoxide dismutase (SOD) activities were determined. Results revealed that in quercetin group erythrocyte CAT levels was found as significantly higher than control group. However, plasma MDA level significantly decreased. In homocysteine group, plasma MDA and carbonil levels significantly increased and erythrocyte GSH and erythrocyte SOD levels significantly decreased than control group.In quercetin +homocysteine group, if compered to homocysteine group, erythrocyte GSH and erythrocyte CAT levels significantly increased and plasma MDA leves significantly decreased.Results as signed that by decreasing MDA level, increasing GSH level and erythrocyte CAT activity quercetin makes positive effects on oxidative stress induced by homocysteine.