Suaeda japonica Makino Attenuates Lipopolysaccharide-Induced Neuro-Inflammatory Responses in BV-2 Microglia via NF-kappa B Signaling

Purpose: To evaluate in vitro anti-oxidant and anti-neuro-inflammatory activities of Suaeda japonica extract (SJE) in lipopolysaccharide (LPS)-stimulated BV-2 microglial cells. Methods: 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay was used to study the antioxidant effects. 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyl-tetrazolium bromide (MTT) assay was used to study cell viabilities. LPS-stimulated BV- microglial cells were used to study the gene expression and production of inflammatory mediators determined by Western blot analysis. Results: SJE significantly inhibited the DPPH generated free radicals, and suppressed LPS-induced expression of inducible nitric oxide synthase (iNOS) and production of nitric oxide (NO) in a concentration-dependent manner. It decreased LPS-induced expression of some inflammatory mediators and pro-inflammatory cytokines (cyclooxygenase-2 and interleukin (IL)-6). This suppression of inflammatory mediators was nuclear factor kappa-B (NF-κB)-dependent. Conclusion: Our findings imply that SJE may be a potential therapeutic agent in regulating microglia-mediated neuroinflammatory responses observed in several neurodegenerative diseases.