The relationship between the antioxidant and the antibacterial properties of galloylated catechins and the structure of phospholipid model membranes
The relationship between the antioxidant and the antibacterial properties of galloylated catechins and the structure of phospholipid model membranes
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DOI：
10.1016/s0891-5849(02)01366-7
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发表时间：
2003-03-15
影响因子：
7.4
通讯作者：
Micol, V
中科院分区：
文献类型：
--
作者：
Caturla, N;Vera-Samper, E;Micol, V
通过差示扫描技术研究了四种儿茶素：(+)-儿茶素 (C)、(-)-表儿茶素 (EC)、(-)-表儿茶素没食子酸酯 (ECG) 和 (-)-表没食子儿茶素没食子酸酯 (EGCG) 对磷脂模型膜物理性质的影响及其与抗氧化和抗菌能力的相关性。 量热法 (DSC)、荧光光谱、红外光谱 (IR)、AAPH 诱导的氧化和泄漏实验。 DSC 数据显示，没食子酰化儿茶素，尤其是 ECG，显着影响磷脂酰胆碱 (PC) 和磷脂酰乙醇胺 (PE) 双层的物理性质。没食子酰化儿茶素表现出比其同系物更高的磷脂/水分配系数，并且浸没在嵌入烃链内的磷脂栅栏中，ECG处于最深位置。相比之下，非没食子酰化儿茶素呈现出靠近磷脂/水界面的浅位置。 ECG 还表现出最高的抗脂质过氧化的抗氧化能力，这与其对 DPH 荧光各向异性的强烈影响（通过流体 PC 双层脂质顺序的增加观察到）以及 DSC 观察到的高度协同转变的存在相关。我们认为，一些没食子酰化儿茶素（例如 ECG）的高抗氧化能力可能部分归因于膜结构的形成，该膜结构显示出对洗涤剂溶解的抵抗力，并且其中磷脂具有紧密堆积的酰基链和高度水合的磷酸基团。值得注意的是，发现PE对于没食子酰化儿茶素促进羧基荧光素从细菌模型膜渗漏至关重要，这表明它们的杀菌活性，至少在膜水平上，可能是由于这些儿茶素对PE的特定作用。 (C) 2003 爱思唯尔科学公司。
The effects of four catechins, (+)-catechin (C), (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin gallate (EGCG), on the physical properties of phospholipid model membranes and the correlation to their antioxidant and antibacterial capacities have been studied by using differential scanning calorimetry (DSC), fluorescence spectroscopy, infrared spectroscopy (IR), AAPH-induced oxidation, and leakage experiments. DSC data revealed that galloylated catechins, especially ECG, affected the physical properties of both the phosphatidylcholine (PC) and phosphatidylethanolamine (PE) bilayers dramatically. Galloylated catechins showed higher phospholipid/water partition coefficients than their homologues and were immersed in the phospholipid palisade intercalating within the hydrocarbon chains, ECG being at the deepest position. In contrast, nongalloylated catechins presented a shallow location close to the phospholipid/water interface. ECG also exhibited the highest antioxidant capacity against lipid peroxidation, which correlated with its strong effect on DPH fluorescence anisotropy (as observed by the increase of the lipid order of fluid PC bilayers) and with the presence of highly cooperative transitions as seen by DSC. We propose that the high antioxidant capacity of some galloylated catechins such as ECG could be partially due to the formation of membrane structures showing resistance to detergent solubilization and in which the phospholipids have tightly packed acyl chains and highly hydrated phosphate groups. Significantly, PE was found to be essential to the promotion of carboxyfluorescein leakage from bacterial model membranes by galloylated catechins, indicating that their bactericidal activity, at least at the membrane level, could be due to the specific effect of these catechins on PE. (C) 2003 Elsevier Science Inc.