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

Background 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. Purpose 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. Study Design 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. Methods 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. Results 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. Conclusion 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.