Biomol Ther.  2013 Jan;21(1):54-59.

Inhibitory Effects of Epigallocatechin-3-Gallate on Microsomal Cyclooxygenase-1 Activity in Platelets

• Lee DH
• Kim YJ
• Kim HH
• Cho HJ
• Ryu JH
• Rhee MH
• Park HJ

Abstract

In this study, we investigated the effect of (-)-epigallocatechin-3-gallate (EGCG), a major component of green tea catechins from green tea leaves, on activities of cyclooxygenase (COX)-1 and thromboxane synthase (TXAS), thromboxane A2 (TXA2) production associated microsomal enzymes. EGCG inhibited COX-1 activity to 96.9%, and TXAS activity to 20% in platelet microsomal fraction having cytochrome c reductase (an endoplasmic reticulum marker enzyme) activity and expressing COX-1 (70 kDa) and TXAS (58 kDa) proteins. The inhibitory ratio of COX-1 to TXAS by EGCG was 4.8. These results mean that EGCG has a stronger selectivity in COX-1 inhibition than TXAS inhibition. In special, a nonsteroid anti-inflammatory drug aspirin, a COX-1 inhibitor, inhibited COX-1 activity by 11.3% at the same concentration (50 microM) as EGCG that inhibited COX-1 activity to 96.9% as compared with that of control. This suggests that EGCG has a stronger effect than that of aspirin on inhibition of COX-1 activity. Accordingly, we demonstrate that EGCG might be used as a crucial tool for a strong negative regulator of COX-1/TXA2 signaling pathway to inhibit thrombotic disease-associated platelet aggregation.

Keyword

(-)-Epigallocatechin-3-gallate (EGCG); Aspirin; Microsomal fraction; Cyclooxygenase-1; Thromboxane synthase

MeSH Terms

Aspirin
Blood Platelets*
Catechin
Cyclooxygenase 1*
Cytochromes c
Endoplasmic Reticulum
Oxidoreductases
Platelet Aggregation
Prostaglandin-Endoperoxide Synthases
Tea
Thromboxane A2
Aspirin
Catechin
Cyclooxygenase 1
Cytochromes c
Oxidoreductases
Prostaglandin-Endoperoxide Synthases
Tea
Thromboxane A2