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.
