Fig. 3. Effect of EGCG on thromboxane synthase activity The platelet F2-cellular fraction (microsomal fraction, 20 μg proteins) was preincubated for 5 min at 37℃ with or without various concentration of EGCG. The reaction was initiated by the addition of 5 μM PGH₂ and terminated by the addition by 1 M citric acid. The activity was reflected by the production of PGH₂ mediated TXB₂, which was determined by TXB₂ EIA kit (GE Healthcare). The data are given as the means ± S.E.M. (n=4). *p<0.05, **p<0.01, ***p<0.001 compared with preincubated F2-cellular fraction without EGCG.