Anti-inflammatory effects of galangin on lipopolysaccharide-activated macrophages via ERK and NF-κB pathway regulation

Inflammation is the major symptom of the innate immune response to microbial infection. Macrophages, immune response-related cells, play a role in the inflammatory response. Galangin is a member of the flavonols and is found in Alpinia officinarum, galangal root and propolis. Previous studies have demonstrated that galangin has antioxidant, anticancer, and antineoplastic activities. However, the anti-inflammatory effects of galangin are still unknown. In this study, we investigated the anti-inflammatory effects of galangin on RAW 264.7 murine macrophages. Galagin was not cytotoxic to RAW 264.7 cells, and nitric oxide (NO) production induced by lipopolysaccharide (LPS)-stimulated macrophages was significantly decreased by the addition of 50 μM galangin. Moreover, galangin treatment reduced mRNA levels of cytokines, including IL-1β and IL-6, and proinflammatory genes, such as iNOS in LPS-activated macrophages in a dose-dependent manner. Galangin treatment also decreased the protein expression levels of iNOS in activated macrophages. Galangin was found to elicit anti-inflammatory effects by inhibiting ERK and NF-κB-p65 phosphorylation. In addition, galangin-inhibited IL-1β production in LPS-activated macrophages. These results suggest that galangin elicits anti-inflammatory effects on LPS-activated macrophages via the inhibition of ERK, NF-κB-p65 and proinflammatory gene expression.