Vasodilator effect of phlomis bracteosa constituents is mediated through dual Endothelium-Dependent and Endothelium-Independent pathways

Khan, A. and Ullah, R. and Mustafa, Mohd Rais and Hussain, J. and Murugan, D.D. and Hadi, A.H.B.A. (2012) Vasodilator effect of phlomis bracteosa constituents is mediated through dual Endothelium-Dependent and Endothelium-Independent pathways. Clinical and Experimental Hypertension, 34 (2). pp. 132-139. ISSN 1064-1963, DOI https://doi.org/10.3109/10641963.2011.601383.

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Abstract

This study describes the vasorelaxant potential of some pure compounds isolated from Phlomis bracteosa L.: marrubiin, phlomeoic acid, and two new constituents labeled as RA and RB. In rat thoracic aortic rings denuded of endothelium, marrubiin, phlomeoic acid, RA, and RB caused relaxation of high K+ (80 mM) and phenylephrine (1 ìM)-induced contractions at the concentration range of 1.0�1000 ìg/mL. Marrubiin, phlomeoic acid, RA, and RB concentration dependently (3.0�10 ìg/mL) shifted the Ca++ curves to the right obtained in Ca++-free medium. The vasodilator effect of marrubiin, phlomeoic acid, RA, and RB was partially blocked by Nù-nitro-L-arginine methyl ester in endotheliumintact aorta preparations. These results reveal that P. bracteosa constituents: marrubiin, phlomeoic acid, RA, and RB exhibit vasodilator action occurred via a combination of endothelium-independent Ca++ antagonism and endotheliumdependent Nù-nitro-L-arginine methyl ester-sensitive nitric oxide-modulating mechanism.

Item Type:	Article
Funders:	UNSPECIFIED
Additional Information:	Address correspondence to Arif-ullah Khan, Center for Natural Products Research and Drug Discovery, Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia. E-mail: arifullahkhan979asia@yahoo.com
Uncontrolled Keywords:	Phlomis bracteosa compounds, vasodilatation, Ca++ channel inhibition, nitric oxide modulation
Subjects:	R Medicine
Divisions:	Faculty of Medicine
Depositing User:	Ms Haslinda Lahuddin
Date Deposited:	12 Jun 2012 04:08
Last Modified:	18 Dec 2019 06:40
URI:	http://eprints.um.edu.my/id/eprint/3294

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