Antihypertensive effects of isoquercitrin and extracts from Tropaeolum majus L.: Evidence for the inhibition of angiotensin converting enzyme
Antihypertensive effects of isoquercitrin and extracts from Tropaeolum majus L.: Evidence for the inhibition of angiotensin converting enzyme
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DOI：
10.1016/j.jep.2010.12.026
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发表时间：
2011-03-24
影响因子：
5.4
通讯作者：
Leite Kassuya, Candida Aparecida
中科院分区：
文献类型：
--
作者：
Gasparotto Junior, Arquimedes;Gasparotto, Francielly Mourao;Leite Kassuya, Candida Aparecida
研究目的：以往的研究表明，从旱金莲L提取物表现出明显的利尿性能。本研究旨在探讨雷公藤水乙醇提取物（HETM）、雷公藤半纯化组分（TMLR）的降压和/或降压机制。和类黄酮异槲皮苷（ISQ）和山奈酚（KPF）可以通过它们与血管紧张素转换酶（ACE）的相互作用来介导。首先，评估平均动脉压（MAP）的变化，不同组别的正常血压和自发性高血压大鼠（SHR）口服和脑内注射HETM 5 - 100 mg/kg）和TMLR（12.5-100 mg/kg），并用ISQ和KPF静脉内处理，随后用氯胺酮（100 mg/kg）和甲苯噻嗪（20 mg/kg）麻醉。分离左股静脉和右颈动脉，插入聚乙烯导管，分别用于ISQ和KPF（0.5-4 mg/kg）给药和血压记录。结果：HETM及其TMLR均能显著降低正常血压大鼠和SHR的MAP，并呈剂量依赖性。此外，这些制剂显著降低了MAP长达3小时后，管理的提取物。此外，静脉注射ISQ而非KPF可降低大鼠的MAP。除此之外，浸提液和ISQ均不影响心率。HETM、TMLR或ISQ的口服给药在给药后90分钟降低血清样品中的ACE活性。最后，静脉注射ISQ引起的高血压反应，血管紧张素I，但不是血管紧张素II在normopressive rats.Conclusion：我们的研究结果表明，HETM，以及其TMLR引起的水肿作用，可能与高水平的类黄酮ISQ在这种植物中发现。此外，ISQ诱导的大鼠低血压是一种依赖于ACE抑制血管紧张素II生成的事件。(C)2010爱思唯尔爱尔兰有限公司版权所有。
Aim of the study: Previous studies have shown that the extracts obtained from Tropaeolum majus L exhibit pronounced diuretic properties. In the present study, we assessed whether the hypotensive and/or antihypertensive mechanism of hydroethanolic extract (HETM), semi-purified fraction (TMLR) obtained from T. majus and the flavonoids isoquercitrin (ISQ) and kaempferol (KPF) can be mediated by their interaction with angiotensin converting enzyme (ACE).Methods and methods: Firstly, to evaluate changes in mean arterial pressure (MAP), different groups of normotensive and spontaneously hypertensive rats (SHR) were orally and intraduodenally treated with HETM (10-300 mg/kg) and TMLR (12.5-100 mg/kg) and intravenously treated with ISQ and KPF being later anesthetized with ketamine (100 mg/kg) and xylazine (20 mg/kg). The left femoral vein and the right carotid artery were isolated, and polyethylene catheters were inserted for ISQ and KPF (0.5-4 mg/kg) administration and blood pressure recording, respectively. The plasmatic ACE activity was evaluated to indirect fluorimetry, in serum samples after orally treatment with HETM, TMLR, ISQ and KPF.Results: The oral administration of the HETM and its TMLR significantly reduced, in a dose-dependent manner, the MAP in both normotensive and SHR. In addition, these preparations significantly decreased the MAP for up to 3 h after the administration of the extract. Additionally, the intravenous administration of ISQ but not KPF, decreased MAP in rats. Otherwise, neither the extracts nor ISQ affected the heart rate. The oral administration of the HETM, TMLR or ISQ reduced ACE activity in serum samples at 90 min after administration. Finally, the intravenous administration of ISQ caused a significant reduction in the hypertensive response to angiotensin I, but not angiotensin II in normotensive rats.Conclusion: Our results show that the hypotensive effects caused by the HETM, as well as by its TMLR, may be associated with the high levels of the flavonoid ISQ found in this plant. In addition, ISQ-induced hypotension in rats is an event dependent on the inhibition of angiotensin II generation by ACE. (C) 2010 Elsevier Ireland Ltd. All rights reserved.