Abdul Jabbar Shah
COMSATS Institute of Information Technology, Pakistan
Title: Antihypertensive effects and potential vascular mechanisms of the extract and fractions of Eruca sativa and Euricin
Biography
Biography: Abdul Jabbar Shah
Abstract
Eruca sativa Mill., (Cruciferae) commonly known as “Rocket” (roquette) or “Arugula” and locally as “Taramera”. Traditionally, Eruca sativa has nutritional values due to the isothiocyanates (eg., euricin) and also been used as a traditional medicine for the management of cardiovascular disorders, particularly hypertension. The aim of the study was to investigate the blood pressure lowering effect of and potential vascular mechanisms of the extract and fractions of Eurca sativa and euricin in hypertensive and normotensive rats and isolated aorta. In in-vivo blood pressure study in normotensive and hypertensive rats under anaesthesia, crude extract of Eruca sativa (Es.Cr) and its nHexane (Es.nHexane), chloroform (Es.Chlor), ethyl acetate (Es.EtAc) and aqueous (Es.Aq) fractions caused a fall in mean arterial pressure (MAP) with more potency in hypertensive rats than normotensive rats. Erucin also caused a fall in MAP in both hypertensive and normotensive rats. In isolated rat aortic rings, crude extract and all fractions induced an endothelium-dependent relaxation mediated by L-NAME sensitive nitric oxide (NO) pathway, while erucin also caused a partial endothelium-dependent vasorelaxation mediated by nitric oxide. When tested against high K+-induced contractions in rat aorta preparations, crude extract and all fractions caused inhibition of the induced contractions. In isolated rabbit aorta, crude extract and all fractions exhibited phentolamine sensitive contractile effect on basal tension, except Es.Chlor. Es.Cr caused relaxation of high K+ (80 mM)-induced and phenylephrine (1 µM) pre-contractions, similar to verapamil, with EC50 values of 5.52 (3.8-7.2) and 7.4 mg/mL (5.8-9), respectively. Erucin also inhibited high K+ (80 mM) and phenylephrine (1 µM) pre-contractions, with EC50 values of 1.1 (0.3–2.0) and 1.8 µg/mL (1.0-2.8), respectively. Among the fractions tested, Es.nHexane, Es.EtAc, and Es.Aq were found more potent against high K+ than PE precontractions except Es.Chlor was equipotent against both PE and high K+. Es.Cr, erucin and all fractions shifted Ca++ concentration–response curves (CRCs) to the right similar to verapamil confirming calcium channel blocking (CCB) activity. The results of this study indicated that crude extract and its fractions possess antihypertensive, vasorelaxant and vasocontractile effects. Vasorelaxant effect mediated by calcium channel blocking and L-NAME sensitive NO mediated endothelium dependent effects. The vasoconstractile effects are mediated partially by α-adrenoceptor stimulation. This combination may provide pharmacological basis of medicinal use of Eruca sativain the treatment of hypertension. This study provides a evidence that medicinal plant extracts posses’ combination of constituents and collectively they act as regulator of body functions while a single compound isolated from same plant may not necessarily represent the pharmacological/biological activities of the parent plant