Selective toxicity of Catechin-a natural flavonoid towards bacteria
Selective toxicity of Catechin-a natural flavonoid towards bacteria
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DOI：
10.1007/s00253-016-7492-x
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发表时间：
2016-07-01
影响因子：
5
通讯作者：
Rao, Jonnalagadda Raghava
中科院分区：
文献类型：
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作者：
Fathima, Aafreen;Rao, Jonnalagadda Raghava
儿茶素是一种植物多酚，由表儿茶素（EC）、表没食子儿茶素（EGC）、表儿茶素没食子酸酯（ECG）和表没食子儿茶素没食子酸酯（EGCG）作为非对构异体组成。在各类黄酮类化合物中，儿茶素被发现是最强大的自由基清除剂，清除氧化损伤产生的活性氧（ROS），具有抗菌和抗炎活性。以革兰氏阳性菌（枯草芽孢杆菌）和革兰氏阴性菌（大肠杆菌）为模式生物，研究了儿茶素对细菌的毒性，发现对革兰氏阳性菌的毒性更大。从结果来看，儿茶素被发现在选择性浓度下对细菌有益和有毒（抑制），就像双刃剑一样，对两种细菌的IC50值都为9ppm。细菌脂质体的形成和处理证实了儿茶素的抑制机制是通过膜透性氧化损伤。对照和处理过的细菌的扫描电镜图像显示膜损伤与形态变化。
Catechin is a plant polyphenol composed of epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG) as diastereoisomers. Among the various classes of flavonoids, catechin was found to be the most powerful free radical scavenger, scavenging the reactive oxygen species (ROS) generated due to oxidative damage with antibacterial and anti-inflammatory activity. The toxicity of catechin towards bacteria was studied using gram-positive bacteria (B. subtilis) and gram-negative bacteria (E. coli) as model organisms and was found to be more toxic towards gram-positive bacteria. From the results, catechin was found to be beneficial as well as toxic (inhibitory) to the bacteria at a selective concentration behaving as double-edged swords with an IC50 value of 9 ppm for both the bacteria. The inhibitory mechanism of catechin was by oxidative damage through membrane permeabilization which was confirmed by the formation and treatment of bacterial liposomes. SEM images of the control and treated bacteria reveals membrane damage with morphological changes.