Neuroprotective Effect of Quercetin during Cerebral Ischemic Injury Involves Regulation of Essential Elements, Transition Metals, Cu/Zn Ratio, and Antioxidant Activity.

Cerebral ischemia results in increased oxidative stress in the affected brain. Accumulating evidence suggests that quercetin possesses anti-oxidant and anti-inflammatory properties. The essential elements magnesium (Mg), zinc (Zn), selenium (Se), and transition metal iron (Fe), copper (Cu), and antioxidants superoxide dismutase (SOD) and catalase (CAT) are required for brain functions. This study investigates whether the neuroprotective effects of quercetin on the ipsilateral brain cortex involve altered levels of essential trace metals, the Cu/Zn ratio, and antioxidant activity. Rats were intraperitoneally administered quercetin (20 mg/kg) once daily for 10 days before ischemic surgery. Cerebral ischemia was induced by ligation of the right middle cerebral artery and the right common carotid artery for 1 h. The ipsilateral brain cortex was homogenized and the supernatant was collected for biochemical analysis. Results show that rats pretreated with quercetin before ischemia significantly increased Mg, Zn, Se, SOD, and CAT levels, while the malondialdehyde, Fe, Cu, and the Cu/Zn ratio clearly decreased as compared to the untreated ligation subject. Taken together, our findings suggest that the mechanisms underlying the neuroprotective effects of quercetin during cerebral ischemic injury involve the modulation of essential elements, transition metals, Cu/Zn ratio, and antioxidant activity.