Effects of external factors on the interaction of tea catechins with lipid bilayers
Effects of external factors on the interaction of tea catechins with lipid bilayers
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DOI：
10.1271/bbb.66.2330
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发表时间：
2002-11-01
影响因子：
1.6
通讯作者：
Nakayama, T
中科院分区：
文献类型：
--
作者：
Kajiya, K;Kumazawa, S;Nakayama, T
绿茶含有高浓度的儿茶素，如(-)-表儿茶素(EC)、(-)-表儿茶素(EGC)、(-)-表儿茶素没食子酸酯(CG)和(-)-表儿茶素没食子酸酯(EGCG)。它们的生物活性已经通过使用培养细胞或细菌的体外实验进行了评估，但各种儿茶素的活性顺序因研究而异。我们一直在研究茶儿茶素与脂双层的相互作用，并阐明了B环上的羟基数目、没食子酸基的存在以及每个儿茶素的立体化学结构决定了它们与脂双层的亲和力。本研究以脂质体膜为模型膜，考察了各种外界因素对茶儿茶素类脂双层亲和力的影响。在水介质中，茶儿茶素掺入脂双层膜的量随盐浓度的增加而增加，随脂双层负电荷的增加而减少。此外，随着EC浓度的增加，EGCG或CG掺入脂双层的量也增加。这些结果表明，水介质中的盐浓度、膜的电荷和其他儿茶素的存在决定了茶儿茶素对脂双层的亲和力。
Green tea contains a high concentration of such catechins as (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg), and (-)-epigallocatechin gallate (EGCg). Their biological activities have been evaluated by in vitro experiments using cultured cells or bacteria, but the order of activity of the various catechins differed with the study. We have been studying the interaction of tea catechins with lipid bilayers, and clarified that the number of hydroxyl groups on the B-ring, the presence of the galloyl moiety, and the stereochemical structure of each catechin govern their affinity for lipid bilayers. We investigated in this present study the effects of various external factors on the affinity of tea catechins for lipid bilayers by using liposomes as model membranes. The amount of tea catechins incorporated into the lipid bilayers increased with increasing salt concentration in an aqueous medium and decreased with increasing negative electric charge of the lipid bilayers. Furthermore, the amount of EGCg or ECg incorporated into the lipid bilayers increased with increasing EC concentration. These results reveal that the salt concentration in an aqueous medium, the electric charge of the membrane, and the presence of other catechins governed the affinity of tea catechins for the lipid bilayers.