Anti-inflammatory effects of Juncus effusus extract (JEE) on LPS-stimulated RAW 264.7 cells and edema models

Juncus effusus L. var. decipiens BUCHEN. f. leschenaultii GAY has been used in traditional medicine for the treatment of anxiety and insomnia.

The objective of this study was to evaluate the effects of ethanol extract from the pith of Juncus effusus (JEE) on anti-inflammatory activities in RAW 264.7 cells.

The production of inflammatory mediators and the underlying mechanisms using 3.1, 6.3, and 12.5 μg/mL concentrations of JEE were investigated. In addition, the topical anti-inflammatory effects of JEE (0.5, 1, and 2 mg/mL) on 12-O-tetradecanoylphorobol-13 acetate (TPA)-induced ear edema and oral administration of JEE (50, 100, and 200 mg/kg) on carrageenan-induced paw-edema were studied in mice.

JEE reduced the release of nitric oxide (NO, IC50 value = 1.98 μg/mL), prostaglandin E2 (IC50 value = 5.5 μg/mL), and pro-inflammatory cytokines, IL-1β (IC50 value = 4.74 μg/mL) and IL-6 (IC50 value = 20.48 μg/mL). JEE also suppressed the protein expression of inducible NO synthase and cyclooxygenase-2 in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Mechanism studies showed attenuation of LPS-induced activation of NF-κB by JEE via abrogation of IκBα degradation and a subsequent decrease in nuclear p65 level. Phosphorylation of all three MAP kinases (ERK, JNK, and p38) in LPS-stimulated RAW 264.7 cells was also suppressed in a dose-dependent manner. In acute inflammation models of mice, topical application (1 and 2 mg) and oral administration (50, 100, and 200 mg/kg) of JEE ameliorated TPA-induced ear edema and carrageenan-induced paw edema, respectively, in dose-dependent manners.

These results indicate that JEE exhibited anti-inflammatory activities by suppressing the production of inflammatory mediators in LPS-stimulated RAW 264.7 cells and by attenuating edema in mice.