A supercritical CO2 extract from seabuckthorn leaves inhibits pro-inflammatory mediators via inhibition of mitogen activated protein kinase p38 and transcription factor nuclear factor-κB

In the present study, we have demonstrated the anti-inflammatory properties of supercritical CO2 extract of seabuckthom leaves (SCE) on mouse alveolar macrophage cell line (MH-S), human peripheral blood mononuclear cells (hPBMCs) in-vitro and in-vivo. Treatment of MM-S cells with SCE (0.5-100 mu g/ml) significantly inhibited lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production. It also inhibited the release of LPS-induced pro-inflammatory cytokines IL-6 and TNF-alpha, which was further confirmed by suppression of LPS induced TNF-alpha in hPBMCs by ELISPOT assay. In addition, western blot analysis demonstrated that SCE decreased LPS-induced inducible nitric-oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression in MM-S cells. Furthermore, SCE treatment also reduced nuclear factor-kappa B (NF-kappa B) translocation in nucleus induced by LPS in MH-S cells. To elucidate the molecular mechanism for inhibition of pro-inflammatory mediators by SCE (100 mu g/ml), we further studied the effect of SCE on LPS-induced p38 mitogen-activated protein kinase (MAPK). It was observed that the phosphorylation of p38 MAPK in LPS-stimulated MH-S cells was significantly inhibited by SCE, which was further proven by suppression of LPS induced CD40 expression. The in-vivo model of AIA mice also showed a significant reduction in the inflammation of paw edema. These data collectively suggest that SCE suppressed the LPS-induced production of NO, IL-6, and TNF-alpha and expression of CD40, iNOS and COX-2 proteins by inhibiting NF-kappa B activation and phosphorylation of p38 MAPK. Hence, the SCE has potent anti-inflammatory activity and might be useful in chronic inflammatory diseases. (C) 2012 Elsevier B.V. All rights reserved.