Hypochromic effect of an aqueous monoglucosyl rutin solution caused by green tea catechins.

Eight catechins reduced the color of a monoglucosyl rutin solution, the gallate-type catechins having a greater effect than the non-gallate-type catechins. Each catechin formed a 1:1 complex with monoglucosyl rutin. The binding constants of the gallate-type catechins were larger than those of the non-gallate type. These results indicate that the degree of color change in the monoglucosyl rutin solution depended on the ability of each catechin to form a complex with monoglucosyl rutin.