Anti-inflammatory mechanism of Isodon japonicas (Burm) Hara on lipopolysaccharide-induced neuroinflammation

Purpose: To investigate the anti-neuroinflammatory effects of Isodon japonicus (Burm.) Hara extract (IJE) on BV2 microglial cells. .Methods: Cell viability was evaluated by MTT method. BV2 microglial cells were stimulated with lipopolyscarride (LPS, 1 μg/ml) and the effect of IJE on nitric oxide (NO) levels were measured using Griess assay. Immunoblot analysis was used to assess the effect of IJE on protein expression of inducible NO synthase (iNOS) expression. Tumor necrosis factor-alpha (TNF-α) cytokine production was evaluated by enzyme-linked immunosorbent assay (ELISA).Results: Pretreatment of 100 mg/ml of IJE (p < 0.001) was inhibited nitric oxide (NO) by 1 ug/ml LPStreated BV-2 cells. iNOS and TNF-α expression were attenuated by IJE concentration-dependently (p < 0.001 at 100 mg/ml). IJE scavenged 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals in a dosedependently with half-maximal inhibitory concentration (IC50) value of 46.5 μg/ml.Conclusion: Data from this study indicate that IJE attenuates neuroinflammatory responses. The strong anti-oxidant effect of IJE modulates expression of inflammatory molecules at the transcription level, and TNF-α at post-transcription level.Keywords: Isodon japonicas, Anti-oxidant, Neuroinflammation, BV-2 microglia, Nitric oxide