Neuroprotective effect of Quince leaf hydroalcoholic extract on intracerebroventricular streptozotocin-induced oxidative stress in cortical tissue of rat brain

Oxidative stress is a result of the imbalance between free radicals and the antioxidant system of the body. Increased oxidative stress in brain causes dysfunction of brain activities, destruction of neurons, and disease such as Alzheimer. Antioxidants, for example vitamins, phenolic compounds and flavonoids have been extensively investigated as potential therapeutic agents in vitro and in vivo for prevention of neurodegenerative diseases. In the present experimental study, the neuro-protective effect of quince leaf hydroalcoholic extract (QLHE) on intracerebroventricular streptozotocin (icv-STZ)-induced oxidative stress in cortical tissue of rat brain was examined. In the present experimental research, forty-two Wistar rats were randomly divided into control, sham, icv-STZ and icv-STZ treated with QLHE groups. The ICV-STZ group rats were injected unilaterally with ICV-STZ (3 mg/kg) using a stereotactic device and QLHE (50, 100 and 150 mg/kg/day) were administered for 6 weeks starting from 3 weeks before of ICV-STZ injection. The rats were killed at the end of the study and their brain cortical tissue superoxide dismutase and catalase activity were measured. The assay of catalase and superoxide dismutase was performed by following the Genet method. The amount of protein was determined according to the Bradford method.The statistical analysis was performed using one way ANOVA. Data were expressed as mean±SD and P<0.05 was considered significant. The present study indicated that in the ICV-STZ group showed significant decrease (P<0.001) in enzymatic antioxidants superoxide dismutase and catalase in the cortical tissue of the brain. Treatment of different doses of QLHE significantly increased superoxide dismutase and catalase activity compared to icv-STZ group (P<0.001) in cortical tissue of the brain. The study demonstrated the effectiveness of quince leaf hydroalcoholic extract as a powerful antioxidant in preventing the oxidative damage by increasing the catalase and superoxide dismutase activity caused by ICV-STZ in cortical tissue of rat brain. Although further studies are needed to clarify the mechanisms of neuroprotective effect of quince leaf, the hydroalcoholic extract seems to partly exert their effects via increasing the antioxidant enzymes activities.