Myrsinane, Premyrsinane, and Cyclomyrsinane Diterpenes from Euphorbia falcata as Potassium Ion Channel Inhibitors with Selective G Protein-Activated Inwardly Rectifying Ion Channel (GIRK) Blocking Effects

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• 作者：Andrea Vasas ; Peter Forgo ; Péter Orvos ; László Tálosi ; Attila Csorba ; Gyula Pinke ; Judit Hohmann
• 刊名：Journal of Natural Products
• 出版年：2016
• 出版时间：August 26, 2016
• 年：2016
• 卷：79
• 期：8
• 页码：1990-2004
• 全文大小：506K
• 年卷期：0
• ISSN：1520-6025

文摘

GIRK channels are activated by a large number of G protein-coupled receptors and regulate the electrical activity of neurons, cardiac atrial myocytes, and β-pancreatic cells. Abnormalities in GIRK channel function have been implicated in the pathophysiology of neuropathic pain, drug addiction, and cardiac arrhythmias. In the heart, GIRK channels are selectively expressed in the atrium, and their activation inhibits pacemaker activity, thereby slowing the heart rate. In the present study, 19 new diterpenes, falcatins A–S (1–19), and the known euphorprolitherin D (20) were isolated from Euphorbia falcata. The compounds were assayed on stable transfected HEK-hERG (Kv11.1) and HEK-GIRK1/4 (Kir3.1 and Kir3.4) cells. Blocking activity on GIRK channels was exerted by 13 compounds (61–83% at 10 μM), and, among them, five possessed low potency on the hERG channel (4–20% at 10 μM). These selective activities suggest that myrsinane-related diterpenes are potential lead compounds for the treatment of atrial fibrillation.