Cardiac Benefits of Black Seed Extract: Its Main Compound Thymoquinone Inhibits Ouabain-Induced Arrhythmia in Isolated Rat Atria



Malihi G¹ ; Nikoui V^{1, 2} ; Pousti A^{1, 3} ; Azam B^{1, 3}
Source: International Journal of Pharmaceutical Research Published:2017

Abstract

Nigella sativa extract (NSE) and thymoquinone (TQ), the active ingredient of black seed (Nigella sativa L.) have shown to be of some benefits in cardiovascular diseases. In this study, we sought to investigate the mechanism of action of NSE and effect of TQ on ouabain-induced arrhythmia in rats. The hearts of male rats divided randomly into several groups, rapidly removed after induction of anesthesia. The atria was immersed in modified Krebs solution and TQ in organ bath connected to a force transducer. In another set of experiments, NSE was extracted from Nigella sativa L. plant and the methanol extract was used in presence of atropine, cyproheptadine and theophylline in organ bath. Time of onset of arrhythmia and asystole, atrial rate and contractile force were recorded and analyzed. This study indicated that TQ significantly postponed the time of onset of arrhythmia and asystole (P≤0.001). Ouabain alone significantly increased the atrial beating rate and contractile force in controls (P≤0.05), whereas pretreatment with TQ reversed this effect. NSE decreased the force and rate of contractions of isolated rat atria dose-dependently (P≤0.05). Pretreatment with atropine, cyproheptadine, and theophylline in the presence of NSE indicated the involvement of cholinergic and serotonergic systems in the mechanism of action of NSE on the isolated rat atria. Based on our findings, NSE has a dose-dependent depressant effect on the heart possibly by direct acting on cholinergic and serotonergic systems, and the antiarrhythmic properties of its active constituent, TQ might be attributed to these systems. © 2017, Association of Indian Pharmacist. All rights reserved.