In vitro inhibition of α-glucosidases and glycogen phosphorylase by catechin gallates in green tea
In vitro inhibition of α-glucosidases and glycogen phosphorylase by catechin gallates in green tea
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DOI：
10.1016/j.foodchem.2010.03.075
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发表时间：
2010-10-15
期刊：
影响因子：
8.8
通讯作者：
Kato, Atsushi
中科院分区：
文献类型：
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作者：
Kamiyama, Ogusa;Sanae, Fujiko;Kato, Atsushi
我们研究了绿茶提取物和儿茶素对哺乳动物碳水化合物降解酶的体外抑制作用，并进一步评价了它们在细胞培养中的抑制活性。该提取物对大鼠肠麦芽糖酶和兔糖原磷酸化酶b有较好的抑制作用，IC50值分别为45和7.4mU g/ml。儿茶素、没食子儿茶素没食子酸酯、表没食子儿茶素没食子酸酯、表没食子儿茶素没食子酸酯和表没食子儿茶素没食子酸酯是麦芽糖酶的良好抑制组分，其IC50值分别为62、67、40和16mU，而儿茶素、没食子儿茶素、表没食子儿茶素和表没食子儿茶素对麦芽糖酶的抑制作用较好，IC50值为27mU。从Dixon图的多重抑制研究中，GCG的IC50值分别为35、6.3、27和34 mU M，GCG似乎结合了一个新的别硬脂酸位点，即吲哚抑制剂位点。这些没食子儿茶素还剂量依赖性地抑制高血糖素刺激的葡萄糖产生，IC50值在33至55亩M之间。添加这些没食子儿茶素或含有它们的绿茶提取物，在体外和细胞培养中都能抑制α-葡萄糖苷酶和糖蛋白，有助于保护或改善2型糖尿病。(C)2010爱思唯尔有限公司。保留所有权利。
We investigated in vitro inhibition of mammalian carbohydrate-degrading enzymes by green tea extract and the component catechins, and further evaluated their inhibitory activities in cell cultures. The extract showed good inhibition toward rat intestinal maltase and rabbit glycogen phosphorylase (GP) b, with IC50 values of 45 and 7.4 mu g/ml, respectively. The polyphenol components, catechin 3-gallate (CG), gallocatechin 3-gallate (GCG), epicatechin 3-gallate (ECG), and epigallocatechin 3-gallate (EGCG), were good inhibitors of maltase, with IC50 values of 62, 67, 40, and 16 mu M, respectively, and EGCG also showed good inhibition toward maltase expressed on Caco-2 cells, with an IC50 value of 27 mu M. The ungallated catechins, such as catechin, gallocatechin (GC), epicatechin (EC), and epigallocatechin (EGC), showed no significant inhibition toward GP b, whereas the gallated catechins CG, GCG, ECG, and EGCG inhibited the enzyme, with IC50 values of 35, 6.3, 27, and 34 mu M. From multiple inhibition studies by Dixon plots, GCG appears to bind a new allostelic site, the indole inhibitor site. These gallated catechins also inhibited glucagon-stimulated glucose production dose-dependently, with IC50 values ranging from 33 to 55 mu M. Dietary supplementation with these gallated catechins or the green tea extract containing them, which inhibits both alpha-glucosidases and GP in vitro and in cell culture, would contribute to the protection or improvement of type 2 diabetes. (C) 2010 Elsevier Ltd. All rights reserved.