Anti-neuroinflammatory Effects of Ethanol Extract of Inula helenium L (Compositae)

Purpose: To evaluate the in vitro antioxidant and anti- neuroinflammatory activities of Inula helenium extract (IHE) against lipopolysaccharide (LPS)-induced production of nitric oxide (NO) by primary microglial cells.Methods: Cell viability was estimated by 3-(4, 5-dimethylthiazol-2- yl)-2, 5- diphenyl-tetrazolium bromide (MTT) assay. Antioxidant activity was evaluated using 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay. LPS-stimulated BV-2 microglia were used to study the expression and production of inflammatory mediators, including NO, inducible NO synthase (iNOS)and Interukin-6 (IL-6).Results: Pretreatment with IHE prior to LPS treatment significantly inhibited excessive production of NO (p < 0.001 at 20, 40, 80 and 100 μg/mL) in a dose-dependent manner, and was associated with downregulation of expression of inducible nitric oxide synthase (iNOS). IHE also suppressed the LPSinduced increase in IL-6 level (p < 0.01 at 40 and 80 μg/mL) in BV-2 cells. The antioxidant activity exhibited by IHE might play a critical role in ameliorating neuroinflammatory processes in LPSstimulated BV-2 microglial cells.Conclusion: IHE may be beneficial in preventing and treating neurodegenerative and oxidative stressrelated diseases.Keywords: Inula helenium, DPPH, Neurodegenerative diseases, Anti inflammatory, Anti-oxidant, Microglial cell