Protective effects of cinnamon bark extract against ischemia-reperfusion injury and arrhythmias in rat

Cinnamomum zeylanicum (cinnamon) is a plant with potent antioxidant activity and has been used in traditional medicine for improvement of heart function. The effects of cinnamon bark ethanolic extract were investigated against ischemia-induced arrhythmias and heart injury in an in vivo rat model of regional heart ischemia. The extract was also standardized, and its antioxidant activity was evaluated. Adult male Sprague-Dawley rats were subjected to 30min of ischemia by occlusion of the left anterior descending coronary artery followed by 5days of reperfusion. Thirty-two animals were randomized to receive daily oral administration of vehicle or C.zeylanicum bark extract (intragastric, 50, 100, or 200mg/kg) 14days before ischemia. C.zeylanicum was standardized through HPLC analysis. Administration of cinnamon bark extract significantly improved ischemia/reperfusion-induced myocardial injury as evidenced by reduction of the infarct size. Also, during the ischemic period, ventricular tachycardia and ventricular ectopic beats episodes decreased as compared with that of the control group. The extract stabilized the ST segment changes and QTc shortening, decreased R-wave amplitude, and increased heart rate during ischemia. The extract also caused significant elevations in serum superoxide dismutase and glutation proxidase activities as well as a significant decrease in serum cardiac troponin I, lactate dehydrogenase, and malondialdehyde levels, 5days after reperfusion. In HPLC analysis, the amounts of Cinamic acid, Methyl eugenol, and Cinnamaldehyde were 8.99 +/- 0.5, 13.02 +/- 1.8, and 14.63 +/- 1.1mg/g, respectively. The results show that the ethanolic extract of cinnamon bark is able to protect the heart against ischemia-reperfusion injury probably due to its antioxidant properties. Hence, it might be beneficial in these patients and this remedy might be used for preparation of new drugs.