Anti-inflammation effects of 8-oxo-9-octadecenoic acid isolated from Undaria peterseniana in lipopolysaccharide-stimulated macrophage cells

Abstract

The aim of this study was to investigate the anti-inflammatory activity of 8-oxo-9-octadecenoic acid (OOA) isolated from Undaria peterseniana by examining its ability to inhibit the lipopolysaccharide (LPS)-induced production of inflammatory mediators in RAW 264.7 macrophage cells. We found that OOA significantly suppressed the LPS-induced production of nitric oxide (NO) and inflammatory cytokines. OOA downregulated the LPS-induced expression of inducible nitric oxide synthase and cyclooxygenase-2 proteins. With respect to proinflammatory signaling pathways, OOA inhibited LPS-induced mitogen-activated protein kinase signaling by inhibiting the phosphorylation of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK). Moreover, OOA inhibited LPS-induced nuclear factor (NF)-κB signaling by reducing the phosphorylation of IκB-α and p50 proteins. These results indicate that OOA significantly reduces proinflammatory signaling, which results in reduced expression of cytokines and proinflammatory mediators. Taken together, these results suggest that OOA has potent anti-inflammatory effects and could be considered an effective anti-inflammatory agent.

Keywords: 8-Oxo-9-octadecenoic acid; Undaria peterseniana; anti-inflammatory; lipopolysaccharide; macrophages.

Figure 1. The chemical structure of 8-oxo-9-octadecenoic acid (OOA)

Figure 2. Effect of 8-oxo-9-octadecenoic acid (OOA) on production of NO in RAW 264.7 cells. Values are expressed as means ± S.D. of triplicate experiments. * P < 0.01 versus the LPS only group

Figure 3. Effects of 8-oxo-9-octadecenoic acid (OOA) on TNF-α and IL-6 production in LPS-induced RAW 264.7 cells. Values are expressed as means ± S.D. of triplicate experiments. * P < 0.01 versus the LPS only group (black bars)

Figure 4. Inhibitory effect of 8-oxo-9-octadecenoic acid (OOA) on the protein levels of iNOS and COX-2 (A); phosphorylation of ERK, JNK, and p38 (B); and phosphorylation of IκB-α and p50 (C) in RAW 264.7 cells. Representative western blots are shown in the left panels and quantitative plots are shown to the right. Values are expressed as means ± S.D. of triplicate experiments. * P < 0.01 versus the LPS only group (black bars)