Carthamus tinctorius L. extract improves hemodynamic and vascular alterations in a rat model of renovascular hypertension through Ang II-AT1R-NADPH oxidase pathway

Carthamus tinctorius L (CT) is widely used in Asian countries as a beverage and in folk medicine. The effects of CT extract on hemodynamics, vascular remodeling, the renin-angiotensin system (RAS) and oxidative stress in the two-kidney, one clip (2K-1C) hypertensive rat model were investigated. Renovascular hypertension was induced in male Sprague-Dawley rats and were treated with CT extract (500 mg/kg/day) or captopril (5 mg/kg/day) or vehicle for four weeks. CT extract or captopril reduced blood pressure, hindlimb vascular resistance, and increased hindlimb blood flow in 2K-1C hypertensive rats (p < 0.05). Increases in aortic wall thickness, cross-sectional area and collagen deposition in 2K-1C rats were alleviated with CT extract or captopril treatment (p < 0.05). CT extract or captopril suppressed RAS activation, including elevated serum ACE activity, and plasma Ang II level and up-regulated aortic AT(1) R protein expression in 2K-1C rats (p < 0.05). Furthermore, CT extract or captopril reduced vascular superoxide production, aortic NADPH oxidase subunit pg91(phox) expression and increased plasma nitric oxide metabolite levels in 2K-1C rats (p < 0.05). These findings suggest that CT extract ameliorated hemodynamic alteration and vascular remodeling in 2K-1C hypertensive rats. Possible mechanisms may involve RAS inhibitor effects and potent antioxidant activity. (C) 2017 Elsevier GmbH. All rights reserved.