Pomegranate juice induces vasorelaxation via endothelium-independent mechanisms and calcium channel blockade in rat aortic smooth muscle.

AIM: By exploring Pomegranate Juice vasorelaxant effects on rat aortic smooth muscle rings, this study bridges traditional wisdom with modern pharmacological investigation, shedding light on the therapeutic potential of this ancient remedy in cardiovascular disorders.

METHODS

Thoracic aortas from adult female albino rats were sectioned into rings and mounted in an organ bath with Krebs' solution at 37 °C. Isometric tension was recorded using a force transducer and PowerLab system. Rings were precontracted with phenylephrine (0.01 mM), and pomegranate juice (1.5-5 mg/ml) effects were assessed. Vasorelaxation was compared between rings with and without endothelium. Specific inhibitors (L-NAME, methylene blue, indomethacin) evaluated the roles of nitric oxide synthase, guanylyl cyclase, and prostaglandin I2. Calcium channel involvement was tested with Nifedipine, an L-type calcium channel blocker.

RESULTS

PJ (1.5-5 mg/ml) induced a concentration-dependent relaxation of aortic rings precontracted with phenylephrine (PE), with an IC₅₀ of 2.859 ± 0.101 mg/ml, indicating its potent vasorelaxant effect. It achieved a maximum relaxation of 81.8 ± 0.358 %, demonstrating its efficacy in relaxing the tissues. PJ also showed significant relaxation effects on intact aortas, irrespective of endothelial denudation or inhibition of nitric oxide synthase, guanylyl cyclase, and cyclooxygenase (COX) inhibitor pathways. PJ also enhanced relaxation in the presence of nifedipine, indicating a possible additive effect and suggesting involvement of complementary vasorelaxant pathways.

CONCLUSION

These findings indicate that pomegranate juice (PJ) relaxes rat aortic rings, resulting in both with and without endothelium aortic ring relaxation.