Protective effect of zingerone on increased vascular contractility in diabetic rat aorta.

The aim of the present study was to investigate the effect and possible mechanism of action of zingerone, the main constituent of ginger, on vascular reactivity in isolated aorta from diabetic rats. The results show that incubation of aortae with zingerone alleviates the exaggerated vasoconstriction of diabetic aortae to phenylephrine, as well as the impaired relaxatory response to acetylcholine in a concentration-dependent manner. Furthermore, Zingerone directly relax phenylephrine-precontracted aortae. The vasorelaxatory response is significantly attenuated by the nitric oxide synthase inhibitor Nω-nitro-l-arginine methyl ester hydrochloride and the guanylate cyclase inhibitor methylene blue but no effect of either the potassium channels blocker tetraethylammonium chloride, or the cyclooxygenase inhibitor indomethacin was observed. Zingerone had no effect on advanced glycation end product formation as well. In conclusion, zingerone ameliorates enhanced vascular contraction in diabetic aortae which may be mediated by its vasodilator effect through NO- and guanylate cyclase stimulation.