Anti-Inflammatory Effects of Methanol Extract of Codium fragile in Lipopolysaccharide-Stimulated RAW 264.7 Cells

Abstract

The methanol extract of Codium fragile (MECF) has been reported to possess bioactive properties such as antidegranulation in eosinophils, as well as anti-edema, antibacterial, and antiviral activities. However, little is known about the molecular effects of MECF on lipopolysaccharide (LPS)-induced inflammation. Therefore, we investigated whether MECF affects the expression of inflammatory mediators in LPS-stimulated RAW 264.7 cells. To evaluate the anti-inflammatory effects of MECF, the cells were pretreated with MECF for 1 hour and then cultured with LPS for 24 hours. Our results indicate that MECF significantly attenuated secretion of LPS-induced inflammatory mediators nitric oxide (NO), prostaglandin E(2) (PGE(2)), and tumor necrosis factor (TNF)-α in RAW 264.7 cells. Additionally, LPS-induced mRNA and protein expression of inducible NO synthase (iNOS), cyclooxygenase (COX)-2, and TNF-α was decreased by pretreatment with MECF. These data indicate that MECF attenuates the expression of these inflammatory mediators at the transcriptional level. Therefore, we also investigated the effects of MECF on nuclear factor-κB (NF-κB) activity, which may be an important transcriptional factor for regulating the expression of iNOS, COX-2, and TNF-α mRNA. Our results showed that MECF reduced LPS-induced NF-κB activity via the suppression of nuclear translocation of the p50 and p65 NF-κB subunits and degradation of inhibitor of κB. In conclusion, we propose that MECF treatment down-regulates the expression and secretion of LPS-induced inflammatory mediators by inhibiting NF-κB activity.