Effects of a Component of Green Tea on the Proliferation of Vascular Smooth Muscle Cells

The effects of a component of green tea on the proliferation of smooth muscle cells were measured in terms of [3H]thymidine uptake. When green tea tannin mixture was added to the medium of cultured smooth muscle cells, it suppressed the proliferation of the cells dose-dependently. Similarly to the effects of the green tea tannin mixture, (-)-epigallocatechin 3-O-gallate, its main ingredient, had an inhibitory effect on smooth muscle cell proliferation at a low concentration. (-)-Epicatechin 3-O-gallate was also an effective component. Among four types of gallate-free tannin, (-)-epigallocatechin, (-)-epicatechin, and (+)-catechin showed significant dose-dependent inhibition of smooth muscle cell proliferation. However, caffeine and theanine were found to have no such action.