Getiye Yohannes, Tolessa Tesfaye, Engidawork Ephrem
Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.
Department of Physiology, School of Medicine, College of Health Sciences, Addis Ababa University, P.O. Box 9086, Addis Ababa, Ethiopia.
J Ethnopharmacol. 2016 Aug 2;189:99-106. doi: 10.1016/j.jep.2016.04.056. Epub 2016 May 3.
Calpurnia aurea (Ait.) Benth. subsp. aurea (CASA) (Fabaceae) seeds are used to treat hypertension in Ethiopian folklore medicine, particularly by Shinasha, Agew-awi and Amhara people in northwest Ethiopia. However, the claim has so far not been substantiated scientifically.
The study was conducted to evaluate the antihypertensive activity of 80% methanol extract of CASA in animal model of hypertension as well as its vasorelaxant effect and possible underlying mechanisms in isolated guinea pig aorta.
Hypotensive and antihypertensive effect of CASA extract was determined in vivo through the intravenous (iv) route in normotensive and hypertensive anesthetized rats using 2-kidney-1-clip (2K1C) rat model. Ex vivo, guinea pig thoracic aortic rings were isolated and suspended in organ bath, and the vasodepressor effects as well as the mechanism of action of the extract were studied by means of isometric tension recording experiments.
The blood pressure fell dose-dependently and significantly in renal hypertensive and normotensive rats following i.v. administration, suggesting that the hydroalcoholic extract possesses hypotensive and antihypertensive effects. The extract also caused a dose-dependent relaxation of aorta pre-contracted with KCl at a concentration of 5-250mg/L, with a maximum relaxation of 92.1% achieved at 250mg/L. The relaxation mechanism was found to be independent of the muscarinic receptors, histamine receptors, ATP dependent K(+) channels, cyclooxygenase enzymes, cGMP/NO pathway and the endothelium system. The extract caused rightward shift of the Ca(++) dose-response curves, similar to that caused by verapamil, indicating that it produced vasorelaxation by inhibiting extracellular Ca(2+) influx.
The findings demonstrate that the plant is endowed with antihypertensive effect, providing evidence for its traditional use. The effect may be, at least in part, due to dilation of blood vessels through blockage of Ca(2+) channels.
金头小冠花（Calpurnia aurea (Ait.) Benth. subsp. aurea (CASA)）（豆科）种子在埃塞俄比亚民间医学中用于治疗高血压，特别是埃塞俄比亚西北部的希纳沙人、阿格维 - 阿维人和阿姆哈拉人使用。然而，这一说法迄今为止尚未得到科学证实。
本研究旨在评估CASA的80%甲醇提取物在高血压动物模型中的降压活性及其在离体豚鼠主动脉中的血管舒张作用和可能的潜在机制。
使用双肾单夹（2K1C）大鼠模型，通过静脉注射途径在正常血压和高血压麻醉大鼠体内测定CASA提取物的降压和抗高血压作用。在体外，分离豚鼠胸主动脉环并悬挂于器官浴槽中，通过等长张力记录实验研究提取物的血管舒张作用及其作用机制。
静脉给药后，肾性高血压和正常血压大鼠的血压呈剂量依赖性显著下降，表明水醇提取物具有降压和抗高血压作用。提取物还能使预收缩的主动脉在5 - 250mg/L浓度的氯化钾作用下产生剂量依赖性舒张，在250mg/L时最大舒张率达到92.1%。发现其舒张机制与毒蕈碱受体（M受体）、组胺受体、ATP依赖性钾通道、环氧化酶、cGMP/NO途径和内皮系统无关。提取物使钙剂量 - 反应曲线右移，类似于维拉帕米引起的右移，表明它通过抑制细胞外钙内流产生血管舒张作用。
研究结果表明该植物具有降压作用，为其传统用途提供了证据。该作用可能至少部分归因于通过阻断钙通道使血管扩张。
