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.
Keywords: Centipedegrass extract; JAK/STAT; NO; iNOS.
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