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The aim of the present study was to evaluate the physiological effect of the Punica granatum hydromethanol seeds extract on the contractility of isolated rat aortic rings. The isolated rat’s thoracic aorta was placed in an organ bath containing Krebs solution and the contraction was recorded isometrically. The results demonstrated that P. granatum hydro- methanol extract (1.5 to 5 mg/ml) caused a significant relaxant effect on the contractions induced by phenylephrine (0.01 mM) with IC50 ± SEM of 2.682 ± 0.197 mg/ml and the percentage of relaxation for PE-induced contraction was 52.88 ± 0.831. In endothelium intact and denuded aortic rings, the extract induced more or less the same response, except at high concentrations used (4.5 – 5.0 mg/ml) in which the endothelium denuded rings produced a significant reduction in the percent of relaxation from 49.91 to 25.42.  Relaxant effect of hydromethanol seed extracts on intact aorta was not affected by nitric oxide synthase sinhsibitor ( L-NAME, 3*10-4), gaunyl cyclase inhibitor ( methylene blue 1*10-5) and PGI2 inhibitor (Indomethacin, 3*10-5), and thus, the percentages of relaxation were 59.85 ± 0.084, 58.59 ± 0.566 and 56.76 ± 0.693 respectively. In addition, incubation of aortic rings with the K+ channels blockers TEA, GLIB,, 4AP and BaCl2, that Kca, KATP and Kv channels played no role on vasorelaxation induced by hydromethanol extract, while Kir enhanced the relaxation induced by the extract to76.40%. Finally, hydro methanol extract significantly enhanced dose-response relaxation after incubation of thoracic aortic rings with Nifedipine (10-6 M) to 91.91 % with IC50 ± SEM 1.774 ± 0.096. It can be concluded from the results of the current work that the fraction of Punica granatum hydromethanol seed extract has vasorelaxant effects on rat aortic which was partially dependent on endothelium, Kir and Ca channels.

Aim of the study: The effects of pomegranate juice and its components on uterine smooth muscle are unknown. Hence, this study aimed to determine the effects of pomegranate juice on the myometrium and investigate their mechanisms of action.Methods Rat uterine smooth muscle horn strips were suspended in organ baths containing Krebs solution. Contractions were measured isometrically using a transducer (AD instrument Australia). The effects of pomegranate juice were evaluated on contractile activity elicited by potassium chloride (KCl 60Mm) depolarization. Inhibitors of nitric oxide (L-NAME 3X10− 4), guanylate cyclase (methylene blue 1*10− 5) and Prostaglandin I2 (indomethacin 3X10− 5); in addition, Potassium Channels blockers, as well as calcium signaling pathways, were determined.Results The juice at concentrations from 1.5-5 mg/ml significantly decreased the rat uterine horn contraction induced by KCl. The inhibitors of NO, cGMP, and PGI2 produced no blocking effect on the relaxation response. Furthermore, the PGI2 inhibitor significantly enhanced the relaxation effects; K + channel blockers did not have any inhibitory effects on the relaxation responses. Contrarily, GLIB significantly improved relaxation. The L-type Ca2 + channel blocker prevented spontaneous contraction of the uterine.Conclusion These findings imply that the active ingredient in pomegranate juice can be used to reduce uterine contractions. Pomegranate juice's action demonstrated that it could aid in treating disorders with uterotonic effects. It may be useful in preventing preterm birth and menstrual cramps, but more research is needed to determine the mechanism of action.Trial registration Code: AEC-013. Registered 23 October 2015.

ABSTRACT:The monoterpene, α-terpinyle acetate (TA) is a constituent of essential oils present in aromatic plants. Since the role of ion channels and endothelial hyperpolarizing factors in TA induced relaxation in rat's aorta is unknown, the current study aimed to study the mechanism underlying the vasodilatory effect of TA in isolated aortic rings. Terpinyle acetate induced a potent vasodilation in rat aortic rings with a percentage of relaxation of 63.79 %. The results of the role of K + channel subtypes in vasorelaxation revealed that both Kv and KATP played a major role since GLIB produced a maximum percent of inhibition in the relaxation produced by TA to 8.91 %; this was followed by 4-AP in which the percent of inhibition reduced to 14.95. On the other hand, Kir played no role in the TA induced vasorelaxation since BaCl2 did not produce any inhibition in aortic relaxation. Furthermore, also L-type Ca 2+ channel played no role in TA induced relaxation since the L-type Ca 2+ channel inhibitor Nifedipine did not reduce the percent of relaxation. Endothelium also played a considerable role in the induced vasorelaxation since, in denuded aorta, the percent of relaxation was reduced to 36%. Preincubation of the aortic ring with methylene blue, a soluble cGMP inhibitor also significantly reduced the TA induced relaxation to 16.39%. In contrast, preincubation with cyclooxygenase inhibitor Indomethacin did not produce any inhibitory effect on AT induced vasorelaxation. It can be concluded from these novel results that AT induced vasorelaxation involve the activation of KV, KATP channels and at least partly dependent on endothelium via the activation NOcGMP signal transduction pathway.