Kobophenol A Isolated from Roots of Caragana sinica (Buc'hoz) Rehder Exhibits Anti-inflammatory Activity by Regulating NF-kappa B Nuclear Translocation in J774A.1 Cells

Kobophenol A (KPA) is a biologically active natural compound isolated from the roots of Caragana sinica (Buc'hoz) Rehder (C. sinica). However, the anti-inflammatory effects of KPA have not been reported. This study aims to find out whether KPA isolated from roots of C. sinica can act as a potential substance on inflammation and analyze the molecular mechanism using the lipopolysaccharide (LPS)-stimulated J774 A.1 macrophage cell line. We showed that KPA treatment significantly suppressed the production of nitric oxide (NO) by inhibiting inducible nitric oxide synthase (iNOS) expression in a dose-dependent manner without cytotoxicity. In the KPA also inhibited pro-inflammatory cytokine gene expression and production, such as interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) in LPS-stimulated J774 A.1 cells. As continuing study on the mechanisms involved, we confirmed that these effects of KPA were related to the inhibition of nuclear factor-kappa B (NF-kappa B) pathway including the suppression of I kappa B kinase alpha/beta (IKK alpha/beta) phosphorylation and translocation of NF-kappa B into the nucleus. Taken together, the present study is the first to demonstrate that KPA isolated from C. sinica suppresses the expression of inflammatory mediators and cytokines by inhibiting NF-kappa B nuclear translocation in LPS-stimulated J774 A.1 macrophages. KPA may be a potential candidate for the treatment of inflammatory diseases in the future.