Anti‐Inflammatory Effects of Antarctic Lichen <i>Umbilicaria antarctica</i> Methanol Extract in Lipopolysaccharide‐Stimulated RAW 264.7 Macrophage Cells and Zebrafish Model

Abstract

<i>Umbilicaria antarctica</i> (UA) is a member of the family Umbilicariaceae. To the best of our knowledge, no studies on its anti-inflammatory effects have been reported yet. In the present study, we examined its ability to suppress inflammatory responses and the molecular mechanisms underlying these abilities using lipopolysaccharide- (LPS-) stimulated RAW 264.7 cells and a zebrafish model of inflammation. We investigated the effects of UA on the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂) in LPS-stimulated RAW 264.7 cells. To explore the anti-inflammatory mechanisms of UA, we measured the mRNA and protein expression of proinflammatory mediators in LPS-stimulated RAW 264.7 cells using quantitative RT-PCR and western blot analyses, respectively. UA significantly inhibited the production of NO, PGE₂, interleukin- (IL-) 6, and tumor necrosis factor- (TNF-) <i>α</i> in the LPS-stimulated RAW 264.7 cells. It also suppressed the mRNA and protein expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and nuclear factor- (NF-) <i>κ</i>B activation in LPS-stimulated RAW 264.7 cells and tail pin-cutting-induced zebrafish model. Collectively, these findings indicate that UA significantly inhibits LPS-stimulated inflammatory responses. These effects were considered to be strongly associated with the suppression of NF-<i>κ</i>B activation. Overall, our results demonstrate that UA extract exerts strong anti-inflammatory activities in <i>in vitro</i> and <i>in vivo</i> models and suggest that UA may be an effective novel therapeutic agent for the treatment of inflammatory diseases.