Affiliations: Department of Applied Biological Chemistry, The
University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
Note: [] Department of Applied Biological Chemistry, Graduate School of
Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo
113-8657, Japan. Fax: +81 3 5841 8026
Abstract: 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.
