Antioxidative and anti-inflammatory effect of Phellinus igniarius on RAW 264.7 macrophage cells

This study investigated the antioxidative and anti-inflammatory effect of Phellinus igniarius (PI) on RAW264.7 mouse macrophages. Cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Measurement of nitric oxide (NO) synthesis was performed using the NO detection. To identify mRNA expressions of cyclooxygenase-2 (COX-2), inducible NO synthase (iNOS), interleukin (IL)-1α, IL-1β, IL-6, and tumor necrosis factor (TNF)-α, real time polymerase chain reaction (PCR) was performed. Assessment of prostaglandin E(2) (PGE(2)) synthesis was performed using the PGE(2) immunoassay. Measurement of free radical scavenging activity was performed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The MTT assay revealed that PI exerted no significant cytotoxicity in the RAW 264.7 macrophage cells. From the PGE(2) immunoassay and NO detection, PGE(2) and NO synthesis were significantly suppressed in the PI treated groups compared to the lipopolysaccharide (LPS) treated groups. Real-time PCR analysis revealed that the mRNA expression of COX-2, iNOS, IL-1α, IL-1β, IL-5, and TNF-α were significantly decreased in the PI treated groups compared to the LPS treated groups. And, PI showed dose-dependent increase in the DPPH radical scavenging activity. In conclusion, PI maybe offer a valuable mode of therapy for the treatment of inflammatory diseases.