Anti-inflammatory effect of Rhus verniviflua Stokes by suppression of iNOS-mediated Akt and ERK pathways: in-vitro and in-vivo studies.

Objectives Rhus verniciflua Stokes (RVS), which has valuable medicinal properties, has for many years been prescribed for inflammation in east Asian medicine. Recent studies suggest that RVS has potent antioxidative, antitumor and anti-inflammatory properties. Methods In this study, the anti-inflammatory effects of RVS in vitro and in vivo were investigated. The ethanol extract from RVS was partitioned with different solvents in order of increasing polarity. Key findings Among the various extracts, the n-butanol extract displayed the most potent activity against nitric oxide and reactive oxygen species. The n-butanol extract also significantly regulates expression of nitric oxide synthase, which inhibits nitric oxide production at the transcriptional level in activated macrophages. Immunoblot analysis also showed that n-butanol extract suppresses the phosphorylation of extracellular signal-regulated kinase and Akt, suggesting that nitric oxide synthase suppression might be mediated via the extracellular signal-regulated kinase and Akt signaling pathways. This study also investigated whether n-butanol exerts an anti-inflammatory effect in an animal model. n-butanol extract significantly reduces carrageenan-induced mouse paw edema at 5 h. Conclusions These results suggest that RVS could be a promising candidate agent for inflammation prevention and combination therapy with anti-inflammatory drugs. [ABSTRACT FROM AUTHOR]