Nutr Res Pract.  2015 Apr;9(2):123-128. 10.4162/nrp.2015.9.2.123.

Protective role of oligonol from oxidative stress-induced inflammation in C6 glial cell

• Ahn JH
• Choi JW
• Choi JM
• Maeda T
• Fujii H
• Yokozawa T
• Cho EJ

• KMID: 2313819
• DOI: http://doi.org/10.4162/nrp.2015.9.2.123

Abstract

BACKGROUND/OBJECTIVES
Natural products or active components with a protective effect against oxidative stress have attracted significant attention for prevention and treatment of degenerative disease. Oligonol is a low molecular weight polyphenol containing catechin-type monomers and oligomers derived from Litchi chinensis Sonn. We investigated the protective effect and its related mechanism of oligonol against oxidative stress.
MATERIALS/METHODS
Oxidative stress in C6 glial cells was induced by hydrogen peroxide (H2O2) and the protective effects of oligonol on cell viability, nitric oxide (NO) and reactive oxygen species (ROS) synthesis, and mRNA expression related to oxidative stress were determined.
RESULTS
Treatment with oligonol inhibited NO and ROS formation under cellular oxidative stress in C6 glial cells. In addition, it recovered cell viability in a dose dependent-manner. Treatment with oligonol also resulted in down-regulated mRNA expression related to oxidative stress, nuclear factor kappa-B (NF-kappaB) p65, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS), compared with the control group treated with H2O2. In particular, expression of NF-kappaB p65, COX-2, and iNOS was effectively reduced to the normal level by treatment with 10 microg/mL and 25 microg/mL of oligonol.
CONCLUSIONS
These results indicate that oligonol has protective activity against oxidative stress-induced inflammation. Oligonol might be a promising agent for treatment of degenerative diseases through inhibition of ROS formation and NF-kappaB pathway gene expression.

Keyword

Oligonol; C6cell; inflammation; nitric oxide; oxidative stress

MeSH Terms

Biological Products
Cell Survival
Cyclooxygenase 2
Gene Expression
Hydrogen Peroxide
Inflammation*
Litchi
Molecular Weight
Neuroglia*
NF-kappa B
Nitric Oxide
Nitric Oxide Synthase Type II
Oxidative Stress
Reactive Oxygen Species
RNA, Messenger
Biological Products
Cyclooxygenase 2
Hydrogen Peroxide
NF-kappa B
Nitric Oxide
Nitric Oxide Synthase Type II
RNA, Messenger
Reactive Oxygen Species

Figure

• 

  Fig. 1 NO formation of C6 cells treated with SNP. After treatment of C6 cells with SNP (500 µM) for 24 h, oligonol (5, 10, and 25 µg/mL) was added for 24 h, and NO formation was then measured by Griess reaction. Values are expressed as mean ± SD. a-cMeans with different letters are significantly different (P < 0.05) by Duncan's multiple range test. Normal, SNP- and oligonol-non-treated cells; Control, SNP-treated cells.

• 

  Fig. 2 Effect of oligonol on viability of C6 glial cells treated with SNP. After treatment of C6 cells with SNP (500 µM) for 24 h, oligonol (5, 10, and 25 µg/mL) was added for 24 h, and cell viability was then measured by MTT assay. Values are expressed as mean ± SD. a-cMeans with different letters are significantly different (P < 0.05) by Duncan's multiple range test. Normal, SNP- and oligonol-non-treated cells; Control, SNP-treated cells.

• 

  Fig. 3 Effect of oligonol on viability of C6 glial cells treated with H2O2. After treatment of C6 cells with H2O2 (500 µM) for 24 h, oligonol (5, 10, and 25 µg/mL) was added for 24 h, and cell viability was then measured by MTT assay. Values are expressed as mean ± SD. a-eMeans with different letters are significantly different (P < 0.05) by Duncan's multiple range test. Normal, H2O2- and oligonol-non-treated cells; Control, H2O2-treated cells.

• 

  Fig. 4 ROS formation of C6 cells treated with H2O2. After treatment of C6 cells with H2O2 (500 µM) for 24 h, oligonol (5, 10, and 25 µg/mL) was added for 24 h, and intracellular ROS was then measured by monitoring the fluorescence increase during 60 min (A) and presented fluorescence intensity at 60 min (B). Values are expressed as mean ± SD. a-bMeans with different letters are significantly different (P < 0.05) by Duncan's multiple range test. Normal, H2O2- and oligonol-non-treated cells; Control, H2O2-treated cells.

• 

  Fig. 5 Effect of oligonol on mRNA expression of NF-κB (A), COX-2 (B), and iNOS (C) under H2O2-induced oxidative stress in C6 glial cells. After treatment of C6 cells with H2O2 (500 µM) for 24 h, oligonol (5, 10, and 25 µg/mL) was added for 24 h. Total RNA was isolated and RT-PCR was performed using indicated primers. The amplified PCR products were run on a 1% agarose gel and visualized by EtBr staining. GAPDH was a house-keeping control gene. Fold ratio = mRNA expression/Normal group. a-dMeans with different letters are significantly different (P < 0.05) by Duncan's multiple range test. Normal, H2O2- and oligonol-non-treated cells; Control, H2O2-treated cells.

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