Olea europaea Linn (Oleaceae) Fruit Pulp Extract Exhibits Potent Antioxidant Activity and Attenuates Neuroinflammatory Responses in Lipopolysaccharide-Stimulated Microglial Cells

Moo-Sung Kim², Sushruta Koppula¹, Seung-Hyo Jung^1,3, Ji-Young Kim^1,3, Hyoung-Ro Lee^1,4, Sang-Rin Lee², Yong-Dae Park², Kyung-Ae Lee², Tae-Kyu Park¹ and Hyun Kang^1*

¹Department of Biotechnology, Research Institute for Biomedical & Health Science, College of Biomedical and Health Science, Konkuk University, Chungju, 380-701, ²R&D Center, Macrocare Tech, Ltd, Ochang, 363-883, ³KuGen Healthcare Institute, Chungju, 380-150, ⁴Nutra MediPharm, Chungju, 380-701 Republic of Korea 

*For correspondence: Email: hkang@kku.ac.kr  Tel: 82-43-840-3603; Fax: 82-43-852-3616 

Received:  26 March 2013                                                                       Revised accepted: 12 April 2013

Tropical Journal of Pharmaceutical Research, June 2013; 12(3): 357-362

Purpose: To investigate the antioxidant and anti-neuroinflammatory potentials of Olea europaea Linn. fruit pulp (OFP-EA) extract in LPS-stimulated BV-2 microglial cells.

Methods: Cell viabilities were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyl-tetrazolium bromide (MTT) assay. Antioxidant properties were evaluated using 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity. Lipopolysaccharide (LPS) was used to stimulate BV-2 microglia. Nitric oxide (NO) production was measured using Griess assay. Inducible NO synthase (iNOS) expression and tumor necrosis factor-alpha (TNF-α) production were measured using enzyme-linked immunosorbent assay (ELISA) and Western blot analysis.

Results: OFP-EA extract significantly (p<0.001 at 20-200 µg/ml, respectively) scavenged the free radicals in a dose-dependent fashion. The increased levels of No stimulated by LPS (34±2.41) were also inhibited by OFP-EA extract significantly and concentration dependently (27±2.32, 21±2.54, 17±1.92 and 11±1.94 at 10, 20, 40 and 80 µg/ml, respectively). Further, OFP-EA suppressed the elevated levels iNOS expression and TNF-α production (p<0.001 at 20, 40 and 80 µg/ml) in LPS-stimulated BV-2 cells.

Conclusion: Results indicate that OFP-EA extract exhibited strong antioxidant properties and inhibited the excessive production of pro-inflammatory mediators such as NO, iNOS and TNF-α in LPS-stimulated BV-2 cells. The antioxidant activity exhibited by OFP-EA extract might play a critical role in ameliorating the inflammatory processes in LPS-stimulated BV-2 microglial cells.