Mechanisms underlying the antihypertensive properties of Urtica dioica.

Rahila Qayyum,Taous Khan,Hafiz Misbah-Ud-Din Qamar,Shamim Khan,Umme Salma,Abdul Jabbar Shah

doi:10.1186/s12967-016-1017-3

Rahila Qayyum, Taous Khan + Show 4 more

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https://doi.org/10.1186/s12967-016-1017-3

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Abstract

BackgroundUrtica dioica has traditionally been used in the management of cardiovascular disorders especially hypertension. The aim of this study was to explore pharmacological base of its use in hypertension.MethodsCrude methanolic extract of U. dioica (Ud.Cr) and its fractions (Ud.EtAc, Ud.nHex, Ud.Chl and Ud.Aq) were tested in vivo on normotensive and hypertensive rats under anesthesia for blood pressure lowering effect. In-vitro experiments on rat and rabbit aortae were employed to probe the vasorelaxation mechanism(s). The responses were measured using pressure and force transducers connected to PowerLab Data Acquisition System.ResultsUd.Cr and fractions were found more effective antihypertensive in hypertensive rats than normotensive with remarkable potency exhibited by the ethyl acetate fraction. The effect was same in the presence of atropine. In isolated rat aortic rings, Ud.Cr and all its fractions exhibited l-NAME sensitive endothelium-dependent vasodilator effect and also inhibit K+ (80 mM)-induced pre-contractions. In isolated rabbit thoracic aortic rings Ud.Cr and its fractions induced relaxation with more potency against K+ (80 mM) than phenylephrine (1 µM) like verapamil, showing Ud.EtAc fraction the most potent one. Pre-incubation of aortic rings with Ud.Cr and its fractions exhibited Ca2+ channel blocking activity comparable with verapamil by shifting Ca2+ concentration response curves to the right. Ud.Cr and its fractions also ablated the intracellular Ca2+ release by suppressing PE peak formation in Ca2+ free medium. When tested on basal tension, the crude extract and all fractions were devoid of any vasoconstrictor effect.ConclusionsThese data indicate that crude methanolic extract and its fractions possess antihypertensive effect. Identification of NO-mediated vasorelaxation and calcium channel blocking effects explain the antihypertensive potential of U. dioica and provide a potential pharmacological base to its medicinal use in the management of hypertension.

Highlights

Urtica dioica has traditionally been used in the management of cardiovascular disorders especially hypertension
In normotensive rats under anesthesia, intravenous administration of Ud.Cr caused a fall in mean arterial pressure (MAP) (Fig. 1a)
The % fall in MAP at respective doses of 1, 3, 10, 30 and 50 mg/kg was 1.68 ± 2.3, 10.74 ± 1.8, 13.85, 7 ± 2.7, 28.81 ± 3.7 and 61.00 ± 8.06 (Fig. 1d)

Summary

Introduction

Urtica dioica has traditionally been used in the management of cardiovascular disorders especially hypertension. Urtica dioica is commonly known as “Nettle”, which comes from word meaning “textile plant” because of its use in the production of silky fabrics [2, 3]. It is known as “Bichu bute” in Urdu, “Kali and Kandale” in Hindko and “Zhoomi joomi” in Shina. The plant prefers to grow on loose soil with organic matter rich in nitrogen and high phosphate levels for rapid growth.

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