Effects of hydroalcoholic extract of Cynodon dactylon (L.) pers. on ischemia/reperfusion-induced arrhythmias

Abstract

Background and purpose of the study: Probable antiarrhythmic effects of Cynodon dactylon (L.) pers. (family Poaceae) against ischemia/reperfusion (I/R)-induced arrhythmias were investigated in isolated rat heart. Methods: The hearts were subjected to 30min regional ischemia followed by 30min reperfusion and perfused with hydroalcoholic extract of rhizome of C. dactylon (25, 50, 100 and 200 mu g/ml). Results: During ischemia, the extract produced marked reduction in the number, duration and incidences of ventricular tachycardia (VT) at 25 and 50 mu g/ml (p<0.001 and p<0.01, respectively). Total number of ischemic ventricular ectopic beats (VEBs) were lowered by 25-100 mu g/ml (p<0.001, p<0.001 and p<0.05, respectively). At the reperfusion phase, C. dactylon (25 and 50 mu g/ml) decreased incidence of VT from 100% (control) to 13 and 33% (p<0.001 and p<0.05) respectively. Duration and number of VT and total VF incidence were also reduced at the same concentration (p<0.05 for all). Perfusion of the extract (25-100 mu g/ml) was markedly lowered reversible VF duration from 218+/-99sec to 0 sec, 0 see and 10+/-5sec (p<0.01, p<0.01 and p<0.05) respectively. Moreover, C. dactylon (25 and 50 mu g/ml) decreased number of total VEBs from 349+/-73 to 35+/-17 (p<0.001) and 66+/-26 (p<0.01). In this study, it was also shown that perfusion of the extract produced a marked and concentration-dependent positive inotropic effect. Conclusion: The findings of this study indicate that C. dactylon produce protective effects against I/R-induced arrhythmias in isolated rat hearts probably by increase in the myocardial contractility and as a result by improvement of hemodynamic factors.