Inhibitory effects of purified green tea epicatechins on contraction and proliferation of arterial smooth muscle cells

AIM: The present study was aimed to examine the vasorelaxant and antiprolif erative responses to purified green tea epicatechin mixture, ( -)epicatechi n and (-)epigallocatechin gallate on rat arterial smooth muscle cells. METH ODS: Changes in isometric force were measured by Grass force transducer and effects on cell proliferation were evaluated using [H-3]thymidine incorpor ation assay. RESULTS: Epicatechin mixture, (-)epicatechin and ( -)epigalloc atechin gallate, which we isolated and purified from jasmine green tea, con centration-dependently, reduced the contractile response to phenylephrine i n rat isolated aortic rings with ( -)epigallocatechin gallate being more ef fective. These three agents also inhibited [H-3]thymidine incorporation int o DNA in cultured rat aortic smooth muscle cells in a concentration-depende nt manner. CONCLUSION: The purified epicatechin derivatives from jasmine gr een tea relaxed the isolated rat arteries preconstricted by phenylephrine a nd inhibited aortic smooth muscle cell proliferation.