Urtica dioica L. leaf extract modulates blood pressure and oxidative stress in spontaneously hypertensive rats

Abstract

Background: Urtica dioica L. (Stinging nettle) has been used for centuries for the treatment of numerous health issues. Purpose: This study investigates the antioxidant capacity and the most abundant phenolic compounds of Urtica dioica L. leaf extract (UE), and its antihypertensive and antioxidative effects in vivo. Study design: Spontaneously hypertensive rats were supplemented with 10, 50, and 200 mg/kg/day of UE and 10 mg/kg/day of losartan during 4-week period. Methods: In this study, HPLC analysis of UE was performed, as well as the determination of antioxidant capacity, superoxide radical scavenging activity, and metal chelating ability. Hemodynamic parameters were measured directly in anesthetized rats. Also, antioxidant enzyme activity and concentration in erythrocytes were determined, as well as systemic oxidative stress and plasma antioxidant status. Results: UE showed higher ferric reducing antioxidant power and Trolox equivalent antioxidant capacity than BHT, but lower than vitamin C. Furthermore, UE showed good metal chelating ability, but weak superoxide radical scavenging activity. All three tested UE doses managed to reduce systolic and diastolic blood pressure, as well as cardiac index, and to improve the antioxidative defense by increasing the activity of superoxide dismutase and catalase, without changing the concentration of the enzymes. Moreover, UE supplementation increased plasma antioxidant capacity and reduced systemic oxidative stress. Conclusion: Chronic UE dietary supplementation had beneficial effects in the experimental model of essential hypertension.