Abstract
Green tea catechins possess potent antioxidative properties, and the preventive effects against various oxidative diseases have been reported. Oxygen radicals in the subendothelial spaces and the penumbra around occluded brain area, play a crucial role in the initiation mechanism of atherosclerosis and stroke, respectively. The purpose of this study was to examine the protective and preventive effects of green tea catechins on atherosclerosis and stroke. Individual pure components of green tea catechins were tested for antiplatelet aggregation property; EGCg and ECg showed 5- and 4-fold potency compared with aspirin. Catechins, especially EGCg and ECg, strongly prevented copper-mediated oxidation of low-density lipoproteins (LDL) in vitro. One-week ingestion of green tea extract significantly prolonged the lag time of LDL oxidation in humans. A long time ingestion of catechin extract greatly prevented the development of atherosclerosis in apoE-deficient mice. In addition, catechin extract protected against cerebral ischemic damage in mid-cerebral artery occluded and reperfused rats; it reduced the score of neurological deficit, reduced brain infarct volume depending on plasma EGCg concentration, and inhibited iNOS expression, neutrophill accumulation and peroxynitrite formation in the penumbra. These results suggest that tea catechins exert beneficial effects on cardiovascular diseases, and support the results of various epidemiological investigations.
