Ismail Azlini, Wan Ahmad Wan Amir Nizam
Department of Fundamental Dental and Medical Sciences, Kulliyyah of Dentistry, International Islamic University Malaysia, Indera Mahkota, Pahang, Malaysia.
Biomedicine Program, School of Health Sciences, Universiti Sains Malaysia, Kelantan, Malaysia.
Pharmacognosy Res. 2017 Dec;9(Suppl 1):S9-S14. doi: 10.4103/pr.pr_69_17.
(Wight) Walp leaves are traditionally used by Malays for treating hypertension. Our previous study showed that aqueous extract of (AESP) and methanolic extract of extracts of leaves significantly reduced blood pressure of normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR).
This study aimed to investigate their vasorelaxation potential and the possible involvement of autonomic receptors and nitric oxide in mediating their effect.
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.
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.
Two-way ANOVA, followed by Bonferroni test was used, where < 0.05 (two-tailed) was considered statistically significant.
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.
Vasorelaxation effect by AESP and MESP involved nitric oxide pathway which is possibly mediated by the autonomic receptors.
This is the first study that reveals significant vasorelaxation effect induced by 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. AESP: Aqueous extract of leaves. MESP: Methanolic extract of leaves. SHR: spontaneously hypertensive rat, WKY: Wistar-Kyoto rat.
（怀特）瓦尔普叶传统上被马来人用于治疗高血压。我们之前的研究表明，（某种植物）叶水提取物（AESP）和甲醇提取物（MESP）能显著降低正常血压的Wistar - Kyoto（WKY）大鼠和自发性高血压大鼠（SHR）的血压。
本研究旨在探究它们的血管舒张潜力以及自主神经受体和一氧化氮在介导其作用过程中可能的参与情况。
两种提取物都将在WKY和SHR的离体胸主动脉环上进行测试。将使用各自的阻滞剂来阐明自主神经受体和一氧化氮的参与情况。
将WKY和SHR的离体胸主动脉环安装到肌张力测定仪腔室上，以测量主动脉张力的变化。将浓度从1μg/ml增加到10mg/ml的AESP和MESP添加到肌张力测定仪腔室中。在添加提取物之前，先预孵育阿托品（1μM）、酚妥拉明（1μM）、普萘洛尔（1μM）和Nω-硝基-L-精氨酸甲酯（100μM）等阻滞剂，分别检查毒蕈碱、α和β肾上腺素能受体（AR）以及一氧化氮的参与情况。
采用双向方差分析，随后进行Bonferroni检验，其中P < 0.05（双侧）被认为具有统计学意义。
AESP和MESP通过一氧化氮途径引起显著的血管舒张。前者通过α-AR介导，而后者由β肾上腺素能受体和毒蕈碱受体介导。
AESP和MESP的血管舒张作用涉及一氧化氮途径，这可能由自主神经受体介导。
这是第一项揭示（某种植物）叶提取物诱导显著血管舒张作用的研究。血管舒张可能是其降低血压能力的可能机制之一。本研究还表明，这种植物提取物的血管舒张作用可能涉及由自主神经受体介导的一氧化氮途径。AESP：（某种植物）叶水提取物。MESP：（某种植物）叶甲醇提取物。SHR：自发性高血压大鼠，WKY：Wistar - Kyoto大鼠。
