Centipedegrass extracts regulate LPS-mediated aberrant immune responses by inhibiting Janus kinase.

<bold>Background: </bold>Centipedegrass extract (CGE) is rich in several polyphenolic compounds including C-glycosylflavonoids, such as maysin and its derivatives, and exerts antioxidant, anti-adipogenic and anticancer effects. However, the effect of CGE on the immune system is unclear.<bold>Purpose: </bold>CGE might inhibit NO production induced by lipopolysaccharide (LPS). In this study, we propose a molecular mechanism for regulation of aberrant immune responses by CGE in LPS-stimulated RAW264.7 cells.<bold>Study Design: </bold>We will preparation of Centipedegrass extract and purify partially in rich of maysin and its derivatives. And examine the effect of the CGE on immune system using LPS-induced RAW cells and animals.<bold>Methods: </bold>LPS-induced nitric oxide (NO) and interleukin-6 levels were measured by enzyme-linked immunosorbent assay. The mRNA and protein levels of immune mediators were analyzed by reverse-transcription polymerase chain reaction and immunoblotting, respectively.<bold>Results: </bold>CGE inhibited LPS-induced NO production in a concentration-dependent manner by suppressing inducible nitric oxide synthase (iNOS) expression in LPS-stimulated cells; this effect was mediated by inhibition of the JAK/STAT pathway. However, CGE did not regulate the expression of other factors, including phosphorylated p38, c-jun N-terminal kinase, or extracellular signal-regulated kinase 1/2. In addition, CGE increased T cells percentage in peripheral blood after oral administration.<bold>Conclusion: </bold>These results indicate that CGE suppresses LPS-induced production of NO and expression of iNOS by directly inhibiting JAK2 kinase activity and enhancing effects on the immune system in mice. [ABSTRACT FROM AUTHOR]