@article {537, title = {Autonomic Receptors and Nitric-Oxide Involvements in Mediating Vasorelaxation Effect Induced by Syzygium polyanthum Leaves Extract}, journal = {Pharmacognosy Research}, volume = {9}, year = {2017}, month = {December 2017}, pages = {s9-s14}, type = {Original Article}, chapter = {s9}, abstract = {

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 {\textmu}g/ ml to 10 mg/ml were added onto the myograph chambers. Blockers such as atropine (1 {\textmu}M), phentolamine (1 {\textmu}M), propranolol (1 {\textmu}M), and Nω-nitro-l-arginine methyl ester (100 {\textmu}M) 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.

}, keywords = {Antihypertensive, Ethnomedicine, Hypertension, Nitric oxide, Syzygium polyanthum, Vasorelaxation}, doi = {10.4103/pr.pr_69_17}, author = {Azlini Ismail and Wan Amir Nizam Wan Ahmad} } @article {454, title = {Teucrium polium-induced Vasorelaxation Mediated by Endothelium-dependent and Endothelium-independent Mechanisms in Isolated Rat Thoracic Aorta}, journal = {Pharmacognosy Research}, volume = {9}, year = {2017}, month = {November 2017}, pages = {372-377}, type = {Original Article}, chapter = {372}, abstract = {

Objective: There are some reports on hypotensive and antispasmodic effects of Teucrium polium L. (Lamiaceae) (TP). Subjects and Methods: The activity of different concentrations of TP extract (1, 2, 4 and 8 mg/ml) was evaluated on contractile responses of isolated aorta to potassium chloride (KCl) and phenylephrine (PE). Results: The cumulative concentrations of the extract induced a concentration-dependent relaxation in the aorta precontracted by PE and KCl. Extract-induced vasorelaxations in denuded aortic rings precontracted by PE and KCl at lower concentrations were considerably less than intact aortic rings, but this effect was significantly more at concentrations of 4 mg/ml for PE-, 4 and 8 mg/ml for KCl-induced contractions. All the extract concentrations (except 1 mg/ml) significantly relaxed PE-induced contraction in the presence of NG-nitro-L-arginine methyl ester. Indomethacin reduced effectively extract-induced vasorelaxation at 1 and 2 mg/ml. The extract reduced PE- and KCl-induced contractions in the presence of cumulative calcium concentrations and after incubation with diltiazem; this vasorelaxant effect of TP was decreased. TP-induced relaxation was inhibited by heparin, ruthenium red, glibenclamide, and tetraethylammonium, but 4-aminopyridine had no effect on TP-induced relaxation. Conclusion: TP extract has vasorelaxant effect on isolated rat thoracic aorta which mediated by endothelium-dependent and endothelium-independent mechanisms. The relaxation mainly was mediated by inhibition of calcium influx in vascular smooth muscle cells. It seems that the vasorelaxant effect of extract at lower concentrations was mediated by nitric oxide and prostacyclin.

}, keywords = {Calcium channels, Isolated aorta, Potassium channels, Teucrium polium, Vasorelaxation}, doi = {10.4103/pr.pr_140_16}, author = {Saeed Niazmand and Elahe Fereidouni and Maryam Mahmoudabady and Mahmoud Hosseini} } @article {866, title = {Vasorelaxant Effect of Diterpenoid lactones from Andrographis paniculata Chloroform Extract on Rat Aortic Rings}, journal = {Pharmacognosy Research}, volume = {2}, year = {2010}, month = {September 2010}, pages = {242-246}, type = {Original Article}, chapter = {242}, abstract = {

Background: The aim of the present study is to evaluate the possible mechanism of the vasorelaxant effect of the Andrographis paniculata chloroform extract (APCE) and diterpenoids, such as, 14-deoxyandrographolide (DA) and 14-deoxy-11, 12-didehydroandrographolide (DDA), on rat aortic rings. Methods: DA and DDA (10 μM to 40 μM) induce relaxation in the aortic rings pre-contracted with KCl (80 mM). Results: The IC50 values are 40.47 {\textpm} 1.44 and 37.43 {\textpm} 1.41\%, respectively, and this inhibition is antagonized by increasing the Ca2+ concentration in the Kreb{\textquoteright}s medium. The results indicate that APCE, DA, and DDA may have a calcium anatgonist property. APCE, DA, and DDA also relax norepinephrene (NE)-induced sustained contractions with IC50 values 41.63 {\textpm} 1.19, 49.22 {\textpm} 2.76, and 37.46 {\textpm} 1.41\% and this relaxant effect is unaffected by the removal of the endothelium or by the presence of indomethacin and Nω-nitro- L-arginine (L-NAME). Moreover, DA and DDA inhibit the phasic and tonic contractions induced by NE in a concentrationdependent manner and show the most potent inhibition on phasic contraction (P \< 0.01). Conclusion: This study shows that APCE, DA, and DDA pre-treatment presents a more potent inhibition compared to post-treatment, after the tension has reached a steady state. These results suggest that the vasorelaxation of APCE, DA, and DDA direct the inhibition of the calcium influx. The vasorelaxant effect is more active in the calcium independent pathway and more sensitive in the intial stage of contraction.

}, keywords = {12-didehydroandrographolide, 14-deoxy-11, 14-deoxyandrographolide, Andrographis paniculata, Aorta, APCE, Vasorelaxation}, doi = {10.4103/0974-8490.69125}, author = {RN Sriramaneni and Ameer Z Omar and Salman M IbrahimX and Salman M Ibrahim and Sadikun Amirin and Asmawi Mohd Zaini} }