Tetrahydrocurcumin alleviates hypertension, aortic stiffening and oxidative stress in rats with nitric oxide deficiency.

Tetrahydrocurcumin (THC), a major metabolite of curcumin, possesses strong antioxidant and cardioprotective properties. However, the activities of THC in hypertension and its associated complications remain unknown. The aim of this study was to investigate the effect of THC on hemodynamic status, aortic elasticity and oxidative stress in rats with N-nitro-L-arginine methyl ester (L-NAME)-induced hypertension. Hypertension was induced in male Sprague-Dawley rats by administration of L-NAME (50 mg kg(-1) body weight) in drinking water for 5 weeks. THC at a dose of 50 or 100 mg kg(-1) per day was administered daily during the fourth and fifth weeks when the hypertensive state had been established. The effects of THC on hemodynamics, aortic elasticity, endothelial nitric oxide synthase (eNOS) protein expression and oxidative stress markers were assessed. Marked increases in blood pressure, peripheral vascular resistance, aortic stiffness and oxidative stress were found in rats after L-NAME administration. THC significantly reversed these deleterious effects by reducing aortic wall thickness and stiffness. These effects were associated with increased aortic eNOS expression, elevated plasma nitrate/nitrite, decreased oxidative stress with reduced superoxide production and enhanced blood glutathione. Our results provide the first evidence that THC attenuates the detrimental effect of L-NAME by improving the hemodynamic status and aortic elasticity concomitant with reduction of oxidative stress. The present study suggests that THC might be used as a dietary supplement to protect against cardiovascular alterations under nitric oxide-deficient conditions.