Cardioprotective effect of ethanolic leaf extract of Melissa officinalis L against regional ischemia-induced arrhythmia and heart injury after five days of reperfusion in rats

Melissa officinalis has antioxidant and anti-inflammatory activities and is used in various diseases. Aim of the study: We investigated the role of M. officinalis extract (MOE) against ischemia-induced arrhythmias and heart injury after five days of reperfusion in an in-vivo rat model of regional heart ischemia. The leaf extract of M. officinalis was standardized through HPLC analysis. Adult male rats were subjected to 30 min of ischemia by occlusion of the left anterior descending coronary artery followed by 5 days of reperfusion. The rats were randomized to receive vehicle or M. officinalis as follows: group I served as saline control with ischemia, groups II, III and IV received different doses of MOE- (intragastric, 25, 50 or 100 mg/kg respectively), by oral gavage daily for14 days prior to ischemia Administration of M. officinalis significantly improved ischemia/reperfusion (I/R)-induced myocardial dysfunction by reduction of infarct size, episodes of ventricular tachycardia(VT) and ventricular ectopic beat(VEB and duration of VT as compared to control group, stabilized ST segment changes, QTc shortening, increased the R and T wave amplitudes and increased the heart rate during ischemia, increased the serum superoxide dismutase (SOD) activity and decreased serum lactate dehydrogenase (LDH), Troponin I (CTnI) and malondialdehyde (MDA) levels, 5 days after reperfusion. MOE-100mg/kg was the effective dose. Cinamic acid (21.81±1.26 mg/gr) was the main phenolic compound of plant sample. The ethanol extract of M. officinalis was observed to exhibit cardioprotective effects against I/R injury, probably due to antioxidant properties. Keywords Melissa officinalis; Ischemia; Reperfusion injury; Heart; Ra