Antioxidant activity of gallate-chitooligosaccharides in mouse macrophage RAW264.7 cells

In this research, a novel derivative of chitooligosaccharides (COS) was synthesized by covalently linking gallic acid and COS (gallate-COS) via carbodiimide to improve cellular antioxidant activity. The direct intracellular radical scavenging effect of gallate-COS by 2',7'-dichlorofluorescin diacetate (DCFH-DA) method, and the inhibition of oxidation of cellular macromolecules, such as DNA, protein and lipid in mouse macrophages (RAW264.7 cells) were determined. Furthermore, with the treatment of gallate-COS, the expression levels of antioxidant enzymes such as superoxide dismutase (SOD) and glutathione (GSH) were significantly increased according to reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. In addition, gallate-COS decreased reactive oxygen species induced activation of the nuclear transcription factor (NF-kappa B). Collectively, these results suggest that gallate-COS can be used as a potential natural compound-based antioxidant in the functional food and pharmaceutical industries. (C) 2011 Elsevier Ltd. All rights reserved.