Konan André B, Datté Jacques Y, Yapo Paul A
Laboratoire de Nutrition et Pharmacologie, Département BA-PA, UFR-Biosciences, Cocody University, Abidjan 22 BP 582 Abidjan 22, Côte d'Ivoire.
BMC Complement Altern Med. 2008 May 27;8:23. doi: 10.1186/1472-6882-8-23.
Sesamum radiatum Schum. & Thonn. (Pedaliaceae) is an annual herbaceous plant, which belongs to the family Pedaliaceae and genus Sesamum. Sesame is used in traditional medicine in Africa and Asia for many diseases treatment. Sesame plant especially the leaves, seed and oil are consumed locally as a staple food by subsistence farmers. The study analyses the relaxation induced by the aqueous extract of leaves from sesame (ESera), compared with those of acetylcholine (ACh) in the guinea-pig aortic preparations (GPAPs), in order to confirm the use in traditional medicine for cardiovascular diseases.
The longitudinal strips of aorta of animals were rapidly removed from animals. The aorta was immediately placed in a Mac Ewen solution. Experiments were performed in preparations with intact endothelium as well as in aortae where the endothelium had been removed. The preparations were suspended between two L-shaped stainless steel hooks in a 10 ml organ bath with Mac Ewen solution. The isometric contractile force of the aorta strips of guinea-pig were recorded by using a strain gauge. All both drugs caused concentration-dependent relaxations responses.
The aqueous extract of leaves from sesame ESera (1 x 10(-7) - 0.1 microg/ml) caused a graded relaxation in GPAPs with intact endothelium, with a EC50-value of 1 x 10(-4) microg/ml. The same effect was observed with ACh (7 x 10(-2) nM - 7 x 10(-1) microM), which caused relaxation in a concentration-dependent manner. The relaxation in response to ESera and, like that to ACh in GPAPs without endothelium, was fully abolished. Destruction of the endothelium or incubation with the nitric oxyde synthase inhibitor (L-NNA) significantly enhanced the inhibition of the relaxation response to ESera. Moreover, all concentrations induced vasoconstrictions. However, L-NNA produced a significant displacement to the right (about 65-fold) of the relaxation response to ESera. Similar results were obtained with ACh. Both diclofenac and tetra-ethyl-ammonium (TEA) pretreatment of GPAPs induced a suppression of the relaxation caused by ESera, and produced a very significant rightward shifts of the CRC (16-fold) for diclofenac and increase the Emax. In contract, the relaxation caused by ACh was not significantly affected by diclofenac or by TEA.
Thus, the present results indicate clearly that the nitric oxide largely contribute to the relaxation effect of Esera and of ACh in GPAPs. In addition, their contractile effects are also mediated by cyclooxygenase activation, and probably the K+ channels involvement, that confirm the use of various preparations of Esera for the treatments of cardiovascular diseases.
辐射芝麻（Sesamum radiatum Schum. & Thonn.）（胡麻科）是一种一年生草本植物，属于胡麻科芝麻属。芝麻在非洲和亚洲的传统医学中用于治疗多种疾病。芝麻植株，尤其是叶子、种子和油，被自给自足的农民当地作为主食食用。本研究分析了芝麻叶水提取物（ESera）与乙酰胆碱（ACh）在豚鼠主动脉制剂（GPAPs）中诱导的舒张作用，以证实其在传统医学中用于治疗心血管疾病的用途。
迅速从动物身上取出主动脉纵向条。主动脉立即置于麦克尤恩溶液中。在内皮完整的制剂以及内皮已被去除的主动脉中进行实验。制剂悬挂在装有麦克尤恩溶液的10毫升器官浴中的两个L形不锈钢钩之间。使用应变片记录豚鼠主动脉条的等长收缩力。两种药物均引起浓度依赖性舒张反应。
芝麻叶水提取物ESera（1×10⁻⁷ - 0.1微克/毫升）在具有完整内皮的GPAPs中引起分级舒张，EC50值为1×10⁻⁴微克/毫升。ACh（7×10⁻²纳摩尔 - 7×10⁻¹微摩尔）也观察到相同效果，其以浓度依赖性方式引起舒张。在无内皮的GPAPs中，对ESera和对ACh的舒张反应完全被消除。内皮破坏或与一氧化氮合酶抑制剂（L-NNA）孵育显著增强了对ESera舒张反应的抑制。此外，所有浓度均诱导血管收缩。然而，L-NNA使对ESera的舒张反应显著右移（约65倍）。ACh也获得了类似结果。双氯芬酸和四乙铵（TEA）对GPAPs的预处理均诱导了对ESera引起的舒张的抑制，双氯芬酸使浓度反应曲线（CRC）非常显著地右移（16倍）并增加最大效应（Emax）。相反，双氯芬酸或TEA对ACh引起的舒张没有显著影响。
因此，目前的结果清楚地表明，一氧化氮在很大程度上促成了ESera和ACh在GPAPs中的舒张作用。此外，它们的收缩作用也由环氧化酶激活介导，并且可能涉及钾通道，这证实了各种ESera制剂用于治疗心血管疾病的用途。
