Dipterocarpus obtusifolius attenuates the effects of lipopolysaccharide-induced inflammatory response in RAW264.7 macrophages

Abstract

Dipterocarpus obtusifolius has been traditionally used as a herbal medicine and is considered to have anticancer properties. The biological activity of D. obtusifolius in inflammation and the underlying mechanisms of its activity remain to be elucidated. The present study investigated the effects of D. obtusifolius methanolic extract (DOME) on lipopolysac-charide (LPS)-stimulated inflammation in RAW264.7 cells. The effects of DOME on the production of nitric oxide, prosta-glandin E2 and pro-inflammatory cytokines were assessed by ELISA, western blot analysis and reverse transcription-quantitative polymerase chain reaction. It was demonstrated that expression of inducible nitric oxide synthase, cyclo-oxygenase-2, interleukin-1β and tumor necrosis factor-α was suppressed by DOME in LPS-stimulated cells. Furthermore, treatment with DOME suppressed phosphorylation of mitogen activated protein kinase (MAPK) molecules, including extracellular signal-regulated kinase, c-Jun N-terminal kinase and p38 MAPK. Translocation of the nuclear factor-κB p65 subunit into the nucleus was additionally inhibited by DOME. Phosphorylation of MAPK promoter activity was inhibited by treatment with DOME, PD98059, SB202190 and SP600125. These results demonstrated that DOME inhibits LPS-induced inflammatory responses. Therefore, DOME may be a potential therapeutic approach for the treatment of inflammatory diseases.