Narirutin fraction from citrus peels attenuates LPS-stimulated inflammatory response through inhibition of NF-κB and MAPKs activation.

In this study, we examined the regulatory activity of narirutin fraction from citrus peels on the production of inflammatory mediators managing acute or chronic inflammatory diseases in macrophages. Narirutin fraction inhibited the release, by lipopolysaccharide (LPS)-stimulated macrophages, of nitric oxide (NO) and prostaglandin E2 (PGE2) through suppressing the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), respectively. The release, by LPS stimulated macrophages, of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) was also reduced by narirutin fraction in a dose-dependent manner. Furthermore, narirutin fraction inhibited the LPS-mediated activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs), which are signaling molecules involved in production of pro-inflammatory factors. As a result of these properties, narirutin fraction has the potential to be used as a functional dietary supplement and effective anti-inflammatory agent.