Citrus peel has long been used in traditional medicine in Asia to treat common cold, dyspepsia, cough, and phlegm. Narirutin is the major flavonoid in citrus peel, and performs anti-oxidative, anti-allergic, and anti-inflammatory functions. However, the anti-inflammatory mechanism of narirutin has not been fully elucidated. This study is aimed to investigate the effects of narirutin on the Nod-like receptor protein 3 (NLRP3)-mediated inflammatory response in vitro and in vivo, and determine the underlying mechanism.
Narirutin suppressed secretion of interleukin (IL)-1β and pyroptosis in lipopolysaccharide (LPS)/ATP-stimulated macrophages. Narirutin decreased the expression of NLRP3 and IL-1β in the LPS-priming step through inhibition of NF-κB, MAPK and PI3K /AKT signaling pathways. Narirutin inhibited NLRP3–ASC interaction to suppress NLRP3 inflammasome assembly. Furthermore, oral administration of narirutin (300 mg/kg) alleviated inflammation symptoms in mice with peritonitis and colitis. These results suggest that narirutin exerts its anti-inflammatory activity by suppressing NLRP3 inflammasome activation by the inhibition of the NLRP3 inflammasome priming processes and NLRP3–ASC interaction in macrophages.
The result has been published in "Phytotherapy Research" under the title of "Narirutin exerts anti-inflammatory activity by inhibiting NLRP3 inflammasome activation in macrophages"(https://doi.org/10.1002/ptr.7686).
