Bioactivity-guided fractionation of an antidiarrheal Chinese herb Rhodiola kirilowii (Regel) Maxim reveals (-)-epicatechin-3-gallate and (-)-epigallocatechin-3-gallate as inhibitors of cystic fibrosis transmembrane conductance regulator.
Bioactivity-guided fractionation of an antidiarrheal Chinese herb Rhodiola kirilowii (Regel) Maxim reveals (-)-epicatechin-3-gallate and (-)-epigallocatechin-3-gallate as inhibitors of cystic fibrosis transmembrane conductance regulator.
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止泻中药红景天 (Regel) 的生物活性引导分馏 Maxim 揭示 (-)-表儿茶素-3-没食子酸酯和 (-)-表没食子儿茶素-3-没食子酸酯作为囊性纤维化跨膜电导调节剂的抑制剂
DOI：
10.1371/journal.pone.0119122
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Yang H
中科院分区：
文献类型：
--
作者：
Chen L;Yu B;Zhang Y;Gao X;Zhu L;Ma T;Yang H
囊性纤维化跨膜传导调节因子（CFTR）是肠毒素诱导的跨上皮液体转运的主要途径。CFTR的抑制已被证实是治疗分泌性腹泻的药物方法。许多传统的中草药，如红景天（Regel）Maxim，长期以来一直用于治疗分泌性腹泻。然而，负责其治疗效果的活性成分仍然未知。本研究的目的是通过生物活性导向的分离策略从红景天中鉴定CFTR抑制剂。我们首先鉴定了抑制CFTR Cl-通道活性的红景天（Rhodiola kirilowii（Regel）Maxim）级分。进一步的生物活性定向分级分离导致鉴定（-）-表没食子儿茶素-3-没食子酸酯（EGCG）为CFTR Cl-通道抑制剂。对5种市售的EGCG类似物（包括（+）-儿茶素（C）、（-）-表儿茶素（EC）、（-）-表没食子儿茶素（EGC）、（-）-表儿茶素-3-没食子酸酯（ECG）和EGCG）的分析显示ECG也具有CFTR抑制活性。在转染的FRT细胞中，EGCG剂量依赖性地可逆地抑制CFTR Cl-通道活性，IC 50值约为100 μM。在离体研究中，EGCG和ECG以剂量依赖性方式抑制离体大鼠结肠粘膜中CFTR介导的短路电流。在小鼠肠闭环模型中，腔内应用EGCG（10 μg）和ECG（10 μg）显著减少霍乱毒素诱导的肠液分泌。CFTR Cl-通道是天然化合物EGCG和ECG的分子靶点。CFTR抑制可能至少部分地解释了红景天的抗真菌活性。EGCG和ECG可能是CFTR相关疾病如分泌性腹泻发展的新先导化合物。
Cystic fibrosis transmembrane conductance regulator (CFTR) is the principal apical route for transepithelial fluid transport induced by enterotoxin. Inhibition of CFTR has been confirmed as a pharmaceutical approach for the treatment of secretory diarrhea. Many traditional Chinese herbal medicines, like Rhodiola kirilowii (Regel) Maxim, have long been used for the treatment of secretory diarrhea. However, the active ingredients responsible for their therapeutic effectiveness remain unknown. The purpose of this study is to identify CFTR inhibitors from Rhodiola kirilowii (Regel) Maxim via bioactivity-directed isolation strategy. We first identified fractions of Rhodiola kirilowii (Regel) Maxim that inhibited CFTR Cl- channel activity. Further bioactivity-directed fractionation led to the identification of (-)–epigallocatechin-3-gallate (EGCG) as CFTR Cl- channel inhibitor. Analysis of 5 commercially available EGCG analogs including (+)–catechins (C), (-)–epicatechin (EC), (-)–epigallocatechin (EGC), (-)–epicatechin-3-gallate (ECG) and EGCG revealed that ECG also had CFTR inhibitory activity. EGCG dose-dependently and reversibly inhibited CFTR Cl- channel activity in transfected FRT cells with an IC50 value around 100 μM. In ex vivo studies, EGCG and ECG inhibited CFTR-mediated short-circuit currents in isolated rat colonic mucosa in a dose-dependent manner. In an intestinal closed-loop model in mice, intraluminal application of EGCG (10 μg) and ECG (10 μg) significantly reduced cholera toxin-induced intestinal fluid secretion. CFTR Cl- channel is a molecular target of natural compounds EGCG and ECG. CFTR inhibition may account, at least in part, for the antidiarrheal activity of Rhodiola kirilowii (Regel) Maxim. EGCG and ECG could be new lead compounds for development of CFTR-related diseases such as secretory diarrhea.