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 E₂ (PGE₂) synthesis was performed using the PGE₂ 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 PGE₂ immunoassay and NO detection, PGE₂ 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.