Chlorella dichloromethane extract ameliorates NO production and iNOS expression through the down-regulation of NF kappa B activity mediated by suppressed oxidative stress in RAW 264.7 macrophages

Background: It has been proposed that chlorella extracts have antioxidative and anti-inflammatory effects. Methods: RAW 264.7 murine macrophage cell line was preincubated with various concentrations (0-100 mug/ml) of chlorella dichloromethane extract (CDE) and stimulated with lipopolysaccharide (LPS) to induce oxidative stress and inflammation. Results: Treatments of CDE reduced thiobarbituric acid-reactive substances (TBARS) accumulation, enhancing glutathione level and activities of antioxidative enzymes including superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-px), and glutathione reductase in LPS-stimulated macrophages than LPS-only treated cells. Nitric oxide (NO) production was significantly suppressed in a dose-dependent manner (p<0.05) with an IC50 of 30.5 mug/ml. Treatment of CDE at 50 mug/ml suppressed NO production to 6% of LPS-control. Treatment with CDE suppressed the levels of inducible nitric oxide synthase (NOS) protein and mRNA expressions. The specific DNA binding activities of nuclear factor kappa B (NFkappaB) on nuclear extracts from CDE treatments were significantly suppressed with an IC50 of 62.7 mug/mI in a dose-dependent manner.