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Autonomic Receptors and Nitric-Oxide Involvements in Mediating Vasorelaxation Effect Induced by Syzygium polyanthum Leaves Extract

CONTEXT: Syzygium polyanthum (Wight) Walp leaves are traditionally used by Malays for treating hypertension. Our previous study showed that aqueous extract of S. polyanthum (AESP) and methanolic extract of S. polyanthum (MESP) extracts of S. polyanthum leaves significantly reduced blood pressure of...

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Autores principales: Ismail, Azlini, Wan Ahmad, Wan Amir Nizam
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Medknow Publications & Media Pvt Ltd 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5757333/
https://www.ncbi.nlm.nih.gov/pubmed/29333036
http://dx.doi.org/10.4103/pr.pr_69_17
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author Ismail, Azlini
Wan Ahmad, Wan Amir Nizam
author_facet Ismail, Azlini
Wan Ahmad, Wan Amir Nizam
author_sort Ismail, Azlini
collection PubMed
description CONTEXT: Syzygium polyanthum (Wight) Walp leaves are traditionally used by Malays for treating hypertension. Our previous study showed that aqueous extract of S. polyanthum (AESP) and methanolic extract of S. polyanthum (MESP) extracts of S. polyanthum leaves significantly reduced blood pressure of normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). AIMS: This study aimed to investigate their vasorelaxation potential and the possible involvement of autonomic receptors and nitric oxide in mediating their effect. SETTINGS AND DESIGN: Both extracts will be tested on isolated thoracic aorta rings of WKY and SHR. The involvement of autonomic receptors and nitric oxide will be elucidated using respective blockers. MATERIALS AND METHODS: Isolated thoracic aorta rings from WKY and SHR were mounted onto myograph chambers to measure changes in the aorta tension. Increasing concentrations of AESP and MESP, from 1 μg/ml to 10 mg/ml were added onto the myograph chambers. Blockers such as atropine (1 μM), phentolamine (1 μM), propranolol (1 μM), and Nω-nitro-l-arginine methyl ester (100 μM) were preincubated before addition of extracts to check for involvement of muscarinic, α- and β-adrenergic receptors (AR) as well as nitric oxide, respectively. STATISTICAL ANALYSIS USED: Two-way ANOVA, followed by post hoc Bonferroni test was used, where P < 0.05 (two-tailed) was considered statistically significant. RESULTS: AESP and MESP caused significant vasorelaxations through nitric oxide pathway. The former was mediated through α-AR while the latter was mediated by β-adrenergic and muscarinic receptors. CONCLUSION: Vasorelaxation effect by AESP and MESP involved nitric oxide pathway which is possibly mediated by the autonomic receptors. SUMMARY: This is the first study that reveals significant vasorelaxation effect induced by Syzygium polyanthum leaves extract. Vasorelaxation maybe one of the possible mechanisms for its ability to reduce blood pressure. This study also suggested that the vasorelaxation effect by this plant extract may involve nitric oxide pathway mediated by the autonomic receptors. [Image: see text] Abbreviations Used: AESP: Aqueous extract of Syzygium polyanthum leaves. MESP: Methanolic extract of Syzygium polyanthum leaves. SHR: spontaneously hypertensive rat, WKY: Wistar-Kyoto rat.
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spelling pubmed-57573332018-01-12 Autonomic Receptors and Nitric-Oxide Involvements in Mediating Vasorelaxation Effect Induced by Syzygium polyanthum Leaves Extract Ismail, Azlini Wan Ahmad, Wan Amir Nizam Pharmacognosy Res Original Article CONTEXT: Syzygium polyanthum (Wight) Walp leaves are traditionally used by Malays for treating hypertension. Our previous study showed that aqueous extract of S. polyanthum (AESP) and methanolic extract of S. polyanthum (MESP) extracts of S. polyanthum leaves significantly reduced blood pressure of normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). AIMS: This study aimed to investigate their vasorelaxation potential and the possible involvement of autonomic receptors and nitric oxide in mediating their effect. SETTINGS AND DESIGN: Both extracts will be tested on isolated thoracic aorta rings of WKY and SHR. The involvement of autonomic receptors and nitric oxide will be elucidated using respective blockers. MATERIALS AND METHODS: Isolated thoracic aorta rings from WKY and SHR were mounted onto myograph chambers to measure changes in the aorta tension. Increasing concentrations of AESP and MESP, from 1 μg/ml to 10 mg/ml were added onto the myograph chambers. Blockers such as atropine (1 μM), phentolamine (1 μM), propranolol (1 μM), and Nω-nitro-l-arginine methyl ester (100 μM) were preincubated before addition of extracts to check for involvement of muscarinic, α- and β-adrenergic receptors (AR) as well as nitric oxide, respectively. STATISTICAL ANALYSIS USED: Two-way ANOVA, followed by post hoc Bonferroni test was used, where P < 0.05 (two-tailed) was considered statistically significant. RESULTS: AESP and MESP caused significant vasorelaxations through nitric oxide pathway. The former was mediated through α-AR while the latter was mediated by β-adrenergic and muscarinic receptors. CONCLUSION: Vasorelaxation effect by AESP and MESP involved nitric oxide pathway which is possibly mediated by the autonomic receptors. SUMMARY: This is the first study that reveals significant vasorelaxation effect induced by Syzygium polyanthum leaves extract. Vasorelaxation maybe one of the possible mechanisms for its ability to reduce blood pressure. This study also suggested that the vasorelaxation effect by this plant extract may involve nitric oxide pathway mediated by the autonomic receptors. [Image: see text] Abbreviations Used: AESP: Aqueous extract of Syzygium polyanthum leaves. MESP: Methanolic extract of Syzygium polyanthum leaves. SHR: spontaneously hypertensive rat, WKY: Wistar-Kyoto rat. Medknow Publications & Media Pvt Ltd 2017-12 /pmc/articles/PMC5757333/ /pubmed/29333036 http://dx.doi.org/10.4103/pr.pr_69_17 Text en Copyright: © 2017 Pharmacognosy Research http://creativecommons.org/licenses/by-nc-sa/3.0 This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
spellingShingle Original Article
Ismail, Azlini
Wan Ahmad, Wan Amir Nizam
Autonomic Receptors and Nitric-Oxide Involvements in Mediating Vasorelaxation Effect Induced by Syzygium polyanthum Leaves Extract
title Autonomic Receptors and Nitric-Oxide Involvements in Mediating Vasorelaxation Effect Induced by Syzygium polyanthum Leaves Extract
title_full Autonomic Receptors and Nitric-Oxide Involvements in Mediating Vasorelaxation Effect Induced by Syzygium polyanthum Leaves Extract
title_fullStr Autonomic Receptors and Nitric-Oxide Involvements in Mediating Vasorelaxation Effect Induced by Syzygium polyanthum Leaves Extract
title_full_unstemmed Autonomic Receptors and Nitric-Oxide Involvements in Mediating Vasorelaxation Effect Induced by Syzygium polyanthum Leaves Extract
title_short Autonomic Receptors and Nitric-Oxide Involvements in Mediating Vasorelaxation Effect Induced by Syzygium polyanthum Leaves Extract
title_sort autonomic receptors and nitric-oxide involvements in mediating vasorelaxation effect induced by syzygium polyanthum leaves extract
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5757333/
https://www.ncbi.nlm.nih.gov/pubmed/29333036
http://dx.doi.org/10.4103/pr.pr_69_17
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