Shimizu M, Kobayashi Y, Suzuki M, Satsu H, Miyamoto Y
Department of Applied Biological Chemistry, The University of Tokyo, Japan.
Biofactors. 2000;13(1-4):61-5. doi: 10.1002/biof.5520130111.
Intestinal glucose uptake is mainly performed by its specific transporters, such as SGLT 1, GLUT 2 and 5 expressed in the intestinal epithelial cells. By using human intestinal epithelial Caco-2 cells we observed that intestinal glucose uptake was markedly inhibited by tea extracts. While several substances in green tea seem to be involved in this inhibition, catechins play the major role and epicatechin gallate (ECg) showed the highest inhibitory activity. Since our Caco-2 cells did not express enough amount of SGLT 1, the most abundant intestinal glucose transporter, the effect of ECg on SGLT 1 was evaluated by using brush border membrane vesicles obtained from the rabbit small intestine. ECg inhibited SGLT 1 in a competitive manner, although ECg itself was not transported via the glucose transporters. These results suggest that tea catechins could play a role in controlling the dietary glucose uptake at the intestinal tract and possibly contribute to blood glucose homeostasis.
肠道葡萄糖摄取主要由其特定转运蛋白完成，如在肠上皮细胞中表达的SGLT 1、GLUT 2和5。通过使用人肠上皮Caco-2细胞，我们观察到茶提取物显著抑制肠道葡萄糖摄取。虽然绿茶中的几种物质似乎参与了这种抑制作用，但儿茶素起主要作用，表儿茶素没食子酸酯（ECg）表现出最高的抑制活性。由于我们的Caco-2细胞未表达足够量的最丰富的肠道葡萄糖转运蛋白SGLT 1，因此通过使用从兔小肠获得的刷状缘膜囊泡评估了ECg对SGLT 1的作用。ECg以竞争性方式抑制SGLT 1，尽管ECg本身不通过葡萄糖转运蛋白转运。这些结果表明，茶儿茶素可能在控制肠道对膳食葡萄糖的摄取中发挥作用，并可能有助于血糖稳态。
