Abstract: Electron spin resonanoe (ESR) has been applied to direct measurement of free radical generation in ischemic perfused rat myocardium at 110K.The results show that the isolated perfused rat heart subjected to 30-minute ischemic followed by 15-second reperfusion induced a significant increase of oxygen free radicals production.It was found that the active oxygen free radicals were about 188% more in ischemic reperfused than those in normal perfused.After pretreatment of the heart with GTP,the oxygen free radicals can be reduced by 71%.These results might indicate that the natural antioxidants GTP can protect the heart from the injuries by ischemic reperfusion.

Key words: Oxygen free radical, Ischemic reperfused, Green tea polyphenols (GTP), ESR