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KMID : 0606920130210010054
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Biomolecules & Therapeutics
2013 Volume.21 No. 1 p.54 ~ p.59
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Inhibitory Effects of Epigallocatechin-3-Gallate on Microsomal Cyclooxygenase-1 Activity in Platelets
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Lee Dong-Ha
Kim Yun-Jung
Kim Hyun-Hong
Cho Hyun-Jeong
Ryu Jin-Hyeob
Rhee Man-Hee
Park Hwa-Jin
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Abstract
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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 μM) 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.
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KEYWORD
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(?)-Epigallocatechin-3-gallate (EGCG), Aspirin, Microsomal fraction, Cyclooxygenase-1, Thromboxane synthase
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