Inhibitory Effect on Thrombin-induced Myosin Light Chain Phosphorylation by Extract of a New Green Tea Cultivar in A7r5 Rat Aortic Smooth Muscle Cells

Abstract

We show that an extract of a new green tea cultivar Cha Chuukanbohon Nou6 (Nou6), which rich in anthocyanin, has an inhibitory effect on myosin regulatory light chain (MRLC) phosphorylation in rat aortic smooth muscle cell line A7r5. The inhibitory effect of Nou6 extract was abolished when the extract was treated with polyvinylpyrrolidone which traps polyphenols.However, none of the major tea constituents tested had an inhibitory effect.In addition, we found that Nou6 extract had a strong effect on reducing the phosphorylation of myosin phosphatase targeting subunit 1 at Thr696. These results suggest that Nou6 extract inhibits MRLC phosphorylation induced by thrombin through activating myosin light chain phosphatase, and polyphenols in the tea extract may contribute to this effect.