BMB Rep. 2016; 49(4): 232-237  
Anti-inflammatory action of ethanolic extract of Ramulus mori on the BLT2-linked cascade
Geun-Soo Park1, Jeong-Keun Kim2 & Jae-Hong Kim1,*
1Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, 2Department of Chemical Engineering and Biotechnology, Korea Polytechnic University, Shihung 15073, Korea
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Received: January 6, 2016; Revised: January 13, 2016; Accepted: February 16, 2016; Published online: April 30, 2016.
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Mulberry tree twigs (Ramulus mori) contain large amounts of oxyresveratrols and have traditionally been used as herbal medicines because of their anti-inflammatory properties. However, the signaling mechanism by which R. mori exerts its anti-inflammatory action remains to be elucidated. In this study, we observed that R. mori ethanol extracts (RME) exerted an inhibitory effect on the lipopolysaccharide (LPS)-induced production of the pro-inflammatory cytokine interleukin-6 (IL-6) in Raw264.7 macrophage cells. Additionally, RME inhibited IL-6 production by blocking the leukotriene B4 receptor- 2 (BLT2)-dependent-NADPH oxidase 1 (NOX1)-reactive oxygen species (ROS) cascade, leading to anti-inflammatory activity. Finally, RME suppressed the production of the BLT2 ligands LTB4 and 12(S)-HETE by inhibiting the p38 kinase- cytosolic phospholipase A2-5-/12-lipoxygenase cascade in LPS-stimulated Raw264.7 cells. Overall, our results suggest that RME inhibits the ‘BLT2 ligand-BLT2’-linked autocrine inflammatory axis, and that this BLT2-linked cascade is one of the targets of the anti-inflammatory action of R. mori.
Keywords: BLT2, IL-6, Ramulus mori, Raw264.7 cells, ROS

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