Ulmus davidiana var japonica Attenuates Neuroinflammatory Responses in Activated BV2 Murine Microglial Cells via Nuclear Factor-KappaB Signaling Pathway

Purpose: To investigate the antioxidant and anti-inflammatory effects of Ulmus davidiana extract (UDE) in lipopolysaccharide (LPS)-stimulated BV-2 cells.Methods: Antioxidant activity was measured using 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay. Cell viability was evaluated using 3 (4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide (MTT) assay. BV-2 cells were stimulated with LPS to study protein expression and production of inflammatory mediators, and determined by Western blot analysis.Results: UDE significantly inhibited DPPH-generated free radicals showing maximum inhibition at 40 μg/mL (p < 0.001). UDE alone did not exhibit any signs of cytotoxicity towards BV-2 cells up to 100 μg/mL concentration. The LPS induced increase in the production of nitric oxide was concentration dependently suppressed with half-maximal concentration (IC50) of 67.4 μg/ mL of UDE (p < 0.05 at 10 μg/mL, p < 0.01 at 20 μg/mL and p < 0.001 at 40 μg/mL, respectively). UDE also inhibited dosedependently the LPS-induced increase in inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions with IC50 of 52.3 ug/ mL. Furthermore, the production of pro inflammatory cytokines, via tumor necrosis factor-α by LPS-stimulation in BV2 murine cells was inhibited dosedependently with IC50 of 85.1 ug/ mL by UDE pretreatment. Mechanistic studies revealed that UDE acts by regulation of nuclear factor kappa-B signaling pathway in LPS-stimulated BV-2 cells.Conclusion: This study shows, for the first time, that UDE possesses antioxidant and anti-inflammatory effects and can be developed as a potential therapeutic agent for ameliorating macrophage-mediated inflammation.Keywords: Ulmus davidiana, Anti-oxidant, Anti-inflammatory, iNOS, NF-κB, MCP-1, ERK