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

Abstract

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-γl)-2,5-diphenyltetra-zolium bromide (MTT) assay. Measurement of nitric oxide (NO) synthe-sis was performed using the NO detection. To identify mRNA expres-sions of cyclooxygenase-2 (COX-2), inducible NO synthase (iNOS), in-terleukin (IL)-1α, IL-1β, IL-6, and tumor necrosis factor (TNF)-α, realtime polymerase chain reaction (PCR) was performed. Assessment of pros-taglandin E2 (PGE2) synthesis was performed using the PGE2 immunoas-say. 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. Re-al-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.