The anti-infarct, antistunning and antiarrhythmic effects of oleuropein in isolated rat heart

Previous studies have reported that oleuropein, the major constituent of olive leaves, has cardioprotective effects. There is no report related to oleuropein and ischemic-reperfusion injuries (cardiac dysfunction and myocardial infarction) as well as preconditioning in rat hearts. 56 male Wistar rats were divided into 7 groups (n=8). Group 1 as the control group and groups 2 to 7 as the treatment groups that received a single dose of oleuropein (100 mg/kg, i.p.) 1, 3, 6, 12, 24 and 48 hours before the excision of the heart, respectively. After these times, their hearts were excised and subjected to 30 min regional ischemia and 120 min reperfusion under Langendorff apparatus. Electrocardiogram and intraventricular pressures were monitored and recorded throughout the procedure. Finally, infarct size was measured by triphenyltetrazolium chloride staining. Compared to the control group, oleuropein significantly reduced infarct size and reperfusion-induced cardiac dysfunction in groups 2 and 3. Oleuropein markedly attenuated both ischemic and reperfusion arrhythmias in groups 2 and 3. There was no significant difference between other groups (4 to 7) than the control group. Heart rate had no significant difference among all of the groups. These results indicate that pretreatment of rats with a single dose of intraperitoneal oleuropein could protect their heart against ischemic-reperfusion injury for at least 3 hours. However, it has no preconditioning effect, since oleuropein had not cardioprotective effects 24 hour later.