Objective: To investigate the protective effects of total polyphenols extracted from Toona sinensis on myocardial ischemia /reperfusion-induced injury in rats.Method: Fifty SD rats were randomly divided into 5 groups: a sham operation group（Sham）

a model group treated by ligation of the left coronary artery plus administration of 0.5% sodium carboxymethyl cellulose（Model）

a group with model animals treated by intragastrical administration of a low dose of total polyphenols extracted from T.sinensis（50 mg·kg-1

XD）

a group treated by a moderate dose（100 mg·kg-1

XZ）

and a group treated by high dose（200 kg-1.XG）.Myocardial ischemia /reperfusion-induced injury was made by legating the left coronary artery（LCA） for 30 min followed by a 120 min reperfusion in anesthetized rats.After reperfusion

the levels of phosphocreatine kinase（CK）

troponin I（cTnI）

superoxide dismutase（SOD） and malondialdehyde（MDA） in serum were detected.Finally

the hearts of rats were cut into 5 pieces and stained by 1% TTC for 15 min;the degree of myocardial infarction was calculated.Result: Compared with the rats in model group

after administrated with polyphenols extracted from T.sinensis

the levels of CK

cTnT-I and MDA in serum were decreased

the activity of SOD was increased

and the severity of myocardial infarction was alleviated.Conclusion: Total polyphenols extracted from T.sinensis played a protective role in myocardial ischemia /reperfusion-induced injury.