Diosmin suppresses the proinflammatory mediators in lipopolysaccharide-induced RAW264.7 macrophages via NF-κB and MAPKs signal pathways.

Diosmin is an unsaturated flavonoid glycoside, presents in citrus fruits. The aim of this study is to investigate the molecular mechanism of diosmin with respect to the NF-κB and MAPKs signaling pathways. Firstly, 10, 20, 30, 40 and 50 µM diosmin were treated to lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The anti-inflammatory effects of diosmin was displayed via measuring prostaglandin E2 (PGE2), nitric oxide (NO), interleukines (IL-6, IL-12), tumor necrosis factor α (TNF-α) production, cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), IL-6, IL-12, TNF-α mRNA levels, and phosphorylation levels of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha (IκB-α) and mitogen-activated protein kinases (MAPKs); JNK, ERK, and p38 in LPS induced RAW264.7 macrophages. Our study showed that especially high concentrations of diosmin decreased NO, PGE2, IL-6, IL-12, TNF-α production and mRNA levels of these mediators (p < 0.05). The expression of phosphorylated-JNK was significantly suppressed by diosmin at 40 and 50 µM concentrations. Furthermore, diosmin significantly inhibited the expression of phosphorylated-ERK, p38, and p-IκB-α in a dose-dependent manner. Our results suggest that diosmin is a potent anti-inflammatory agent and has potential for development into a therapeutic agent for inflammation-associated disorders.