Nitric oxide plays a pivotal role in cardioprotection induced by pomegranate juice against myocardial ischemia and reperfusion.

Pomegranate juice (Pg) has demonstrated cardiovascular beneficial effects. The current research intends to investigate the roles of nitric oxide (NO) and antioxidants in Pg-induced cardioprotection against ischemia and reperfusion (I/R). Isolated hearts from anesthetized rats were subjected to 30-min global ischemia followed by 120-min reperfusion. The hearts in the test groups were treated with Pg, N -nitro-L-arginine methyl ester (L-NAME) or both throughout the experiment. In Pg group, left ventricular developed pressure, rate of rise in left ventricular pressure (dp/dt max), and rate pressure product were 83%, 55%, and 127%, respectively, higher than those of the control group (p < 0.05). The infarct size declined to less than 40% (p < 0.0001), and biomarkers of myocardial damage including creatine kinase-MB, lactate dehydrogenase, and troponin-I, showed significant reductions (59%, 36%, and 94%, respectively) compared with the control. Furthermore, the indices of oxidative status including superoxide dismutase, glutathione peroxidase, catalase, and malondialdehyde showed significant improvement (2.4, 1.7, 1.9, and 2.4 fold, respectively). Most of these effects were mainly blocked by L-NAME. These results suggest potent cardioprotective effects for Pg against myocardial I/R injury. The current results suggest a key role for NO for this cardioprotection; however, other mechanisms seem to be also involved.