Inhibitory effect of essential oil from Agastache rugosa against nitric oxide (NO) production induced by inducible nitric oxide synthase (iNOS) over-expression through NF-κB and mitogen-activated protein kinase (MAPK) activation in lipopolysaccharide (LPS)-stimulated RAW264.7 cells

Abstract

In this study, the anti-inflammatory effect of the essential oil from Agastache rugosa (EOA) in RAW264.7 cells was evaluated. The effect of EOA on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells was examined. EOA inhibited NO over-production, which was accompanied by the down-regulation of inducible nitric oxide synthase (iNOS) expression, as evaluated by western blot. To elucidate the action mode of EOA for inhibiting iNOS expression, the effects of EOA on phosphorylation and degradation of IκB-α, p65 nuclear translocation, and NF-κB activation was evaluated. EOA suppressed NF-κB activation through inhibiting the hyper-phosphorylation and degradation of IκB-α. In addition, EOA also inhibited the LPS-induced hyper-phosphorylation of mitogen-activated protein kinases (MAPKs), p38, extracellular signal-regulated kinase-1/2 (ERK1/2), and N-terminal kinase (JNK). Key words: Essential oil, Agastache rugosa, anti-inflammation, inducible nitric oxide synthase (iNOS), NF-κB, mitogen-activated protein kinase (MAPK).