Protective effects of the green tea polyphenol (-)-epigallocatechin gallate against hippocampal neuronal damage after transient global ischemia in gerbils

Recent studies have shown that green tea polyphenols reduce free radical-in duced lipid peroxidation. Oxygen free radical injury plays an important rol e in neuronal damage induced by brain ischemia and reperfusion. The purpose of this study was to examine whether (-)-epigallocatechin gallate (EGCG) w ould reduce neuronal damage after transient global ischemia in the gerbils because EGCG has a potent antioxidant property as a green tea polyphenol. T o produce transient global ischemia, both common carotid arteries were occl uded for 3 min with microaneurysmal clips. The gerbils were treated with EG CG (10, 25, or 50 mg/kg, i.p.) immediately after ischemia. Neuronal cell da mage in the hippocampal CA1 region was evaluated quantitatively 5 days afte r ischemia by a blinded investigator. EGCG at the dose of 10 mg/kg failed t o reduce hippocampal neuronal damage. However, EGCG when administered at th e dose of 25 or 50 mg/kg significantly reduced hippocampal neuronal damage in a dose-dependent manner (P < 0.001, respectively). The present results s how that the green tea polyphenol, EGCG, has a neuroprotective effect again st neuronal damage following global ischemia in the gerbils. (C) 2000 Elsev ier Science Ireland Ltd. All rights reserved.