Suppressive effects of furonaphthoquinone NFD-37 on the production of lipopolysaccharide-inducible inflammatory mediators in macrophages RAW 264.7

2-Methyl-2-(2-methylpropenyl)-2,3-dihydronaphthoquinone[2,3-b]furan-4,9-dione (NFD-37) is a synthetic furonaphthoquinone compound. In this study, we determined that NFD-37 could inhibit the lipopolysaccharide (LPS)-induced production of inflammatory mediators in macrophages RAW 264.7. This compound inhibited LPS-induced nitric oxide (NO) or prostaglandin (PG) E2 production in dose-dependent manners, with IC50 values of 7.2 μM and 5.3 μM, respectively. As the positive controls, pyrrolidine dithiocarbamate (30 μM) exhibited a 57% inhibition of NO production, and NS-398 (1 μM) manifested a 48% inhibition of PGE2 production. The inhibitory effects of NFD-37 on NO and PGE2 production were determined to occur in conjunction with the suppression of inducible NO synthase or cyclooxygenase-2 expression. NFD-37 also inhibited the production of LPS-inducible tumor necrosis factor-α, interleukin (IL)-1β and IL-6, at IC50 values of 4.8–8.9 μM. We also determined the anti-inflammatory efficacy of NFD-37 using carrageenin-induced paw edema in experimental mice.