Gyeji-tang water extract exerts anti-inflammatory activity through inhibition of ERK and NF-κB pathways in lipopolysaccharide-stimulated RAW 264.7 cells.

Abstract

BackgroundGyeji-tang (GJT, Guizhi Tang in Chinese, Keishi-to in Japanese) is a traditional herbal decoction composed of 5 medicinal herbs. GJT has been used to treat the common cold, headaches, and fever in Asian countries including Korea, China, and Japan. In the present study, we investigated the inhibitory effect of a water extract of GJT on inflammatory response using the murine macrophage cell line, RAW 264.7.MethodsRAW 264.7 macrophages were treated with lipopolysaccharide (LPS) to upregulate inflammatory genes. Cells were pretreated with various concentrations of GJT for 4 h and stimulated with LPS for an additional 20 h. Productions of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), cyclooxygenase-2 (COX-2), and prostaglandin E2 (PGE2) were measured by enzyme-linked immunosorbent assays (ELISAs). Protein expressions of heme oxygenase (HO)-1, extracellular signal-regulated kinase (ERK), and nuclear factor kappa-B (NF-κB) were analyzed by immunoblotting.ResultsTreatment with the GJT extract enhanced expression of HO-1 in macrophages without cytotoxicity. GJT extract significantly inhibited proinflammatory cytokines TNF-α and IL-6 in LPS-stimulated cells. GJT suppressed LPS-induced COX-2 expression, leading to a decrease in COX-2-derived PGE2 level. In addition, GJT extract prevented phosphorylation of ERK and NF-κB translocalization to the nucleus in LPS-treated RAW 264.7 cells.ConclusionThese data suggest that GJT has anti-inflammatory possibly through blocking ERK and NF-κB signaling pathways.