Oolong Tea Theasinensins Attenuate Cyclooxygenase-2 Expression in Lipopolysaccharide (LPS)-Activated Mouse Macrophages: Structure−Activity Relationship and Molecular Mechanisms
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- 作者：De-Xing Hou ; Satoko Masuzaki ; Shunsuke Tanigawa ; Fumio Hashimoto ; Jihua Chen ; Takayuki Sogo ; Makoto Fujii
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2010
- 出版时间：December 22, 2010
- 年：2010
- 卷：58
- 期：24
- 页码：12735-12743
- 全文大小：995K
- 年卷期：v.58,no.24(December 22, 2010)
- ISSN：1520-5118
文摘
Oolong tea theasinensins are a group of tea polyphenols different from green tea catechins and black tea theaflavins. The present study reports the inhibitory effects of oolong tea theasinensins on the expression of cyclooxygenase-2 (COX-2) and underlying molecular mechanisms in lipopolysaccharide (LPS)-activated murine macrophage RAW264 cells. The structure−activity data revealed that the galloyl moiety of theasinensins played an important role in the inhibitory actions. Theasinensin A, a more potent inhibitor, caused a dose-dependent inhibition of mRNA, protein, and promoter activity of COX-2. An electrophoretic mobility shift assay (EMSA) revealed that theasinensin A reduced the complex of NF-κB− and AP-1−DNA in the promoter of COX-2. Signaling analysis demonstrated that theasinensin A attenuated IκB-α degradation, nuclear p65 accumulation, and c-Jun phosphorylation. Furthermore, theasinensin A suppressed the phosphorylation of MAPKs, IκB kinase α/β (IKKα/β), and TGF-β activated kinase (TAK1). These data demonstrated that the down-regulation of TAK1-mediated MAPKs and NF-κB signaling pathways might be involved in the inhibition of COX-2 expression by theasinensin A. These findings provide the first molecular basis for the anti-inflammatory properties of oolong tea theasinensins.