Pharmacology Laboratory, Medicinal Plants and Horticultural Resources Division, Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Government of India, Takyelpat Institutional Area, Imphal, Manipur 795001, India.
J Ethnopharmacol. 2012 Aug 30;143(1):207-12. doi: 10.1016/j.jep.2012.06.025. Epub 2012 Jun 23.
The present investigation was aimed to justify the pharmacological basis in traditional use of Clerodendrum colebrookianum as antihypertensive agent in north-east India.
The aqueous extract (AECc), its aqueous, n-butanol (nBFCc), Ethyl-acetate (EtFCc) and Chloroform fractions of C. colebrookianum leaves were evaluated for antihypertensive potential by using fructose-induced hypertension model in rats and in isolated frog heart. The ex-vivo muscarinic action in isolated rat ileum, in-vitro assay for Rho-kinase (ROCK -II), phosphodiesterase-5 (PDE-5) and angiotension converting enzyme (ACE) were also carried out to establish the mechanism of action of samples. The total phenolic and flavonoied contents in test samples were estimated to establish phyto-pharmacological relationship.
The 100μg/mL test samples were showed calcium antagonism in rat ileum and at 50μg/mL and 75μg/mL doses exhibited ROCK-II and PDE-5 inhibition respectively where, EtFCc was caused maximum 68.62% (ROCK-II) and 52.28% (PDE-5) inhibition, but none of the sample was exhibit effect in ACE at 100μg/mL. The test samples also showed negative inotropic and chronotropic effect on isolated frog heart and significant (P<0.001) reduction in systolic blood pressure and heart rate in hypertensive rats compared to control. The total phenolic content maximum 80μg gallic acid equivalents in nBFCc and flavonoids content maximum 69.57μg Quercetin equivalent in AECc were estimated.
These observations established the traditional claim and thus C. colebrookianum could be a potent antihypertensive agent for use in future. The antihypertensive effect mediated by cholinergic action and following ROCK - II, PDE-5 inhibition of C. colebrookianum.
本研究旨在验证印度东北部传统上使用穿心莲作为抗高血压药物的药理学基础。
采用果糖诱导的高血压大鼠模型和离体蛙心，评价穿心莲叶的水提取物（AECc）、水相、正丁醇（nBFCc）、乙酸乙酯（EtFCc）和氯仿部分的降压潜力。还进行了离体大鼠回肠的毒蕈碱作用、Rho-激酶（ROCK-II）、磷酸二酯酶-5（PDE-5）和血管紧张素转化酶（ACE）的体外测定，以确定样品的作用机制。还测定了测试样品中的总酚和类黄酮含量，以建立植物药理学关系。
100μg/mL 的测试样品在大鼠回肠中表现出钙拮抗作用，在 50μg/mL 和 75μg/mL 剂量下分别表现出 ROCK-II 和 PDE-5 抑制作用，其中 EtFCc 引起最大的 68.62%（ROCK-II）和 52.28%（PDE-5）抑制作用，但在 100μg/mL 时没有一种样品对 ACE 有作用。测试样品还对离体蛙心表现出负性变力和变时作用，并与对照组相比，显著降低高血压大鼠的收缩压和心率（P<0.001）。在 nBFCc 中最大总酚含量为 80μg 没食子酸当量，在 AECc 中最大黄酮含量为 69.57μg 槲皮素当量。
这些观察结果证实了传统的说法，因此穿心莲可能是一种用于未来的有效抗高血压药物。穿心莲通过胆碱能作用和随后的 ROCK-II、PDE-5 抑制介导的降压作用。
