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

Khan, A.; Ullah, R.; Mustafa, M.R.; Hussain, J.; Murugan, D.D.; 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

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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
    Creators:
    1. Khan, A.
    2. Ullah, R.
    3. Mustafa, M.R.(Department of Pharmacology, Faculty of Medicine Building, University of Malaya, 50603 Kuala Lumpur, MALAYSIA)
    4. Hussain, J.
    5. Murugan, D.D.
    6. Hadi, A.H.B.A.
    Journal or Publication Title: Clinical and Experimental Hypertension
    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 12:08
    Last Modified: 12 Jun 2012 12:08
    URI: http://eprints.um.edu.my/id/eprint/3294

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