Effects of taraxasterol on inflammatory responses in lipopolysaccharide-induced RAW 264.7 macrophages

Aim of the study: Taraxasterol, a pentacyclic-triterpene, was isolated from the Chinese medicinal herb Taraxacum officinale. In the present study, we investigated the in vitro anti-inflammatory activity of taraxasterol in lipopolysaccharide (LPS)-induced RAW 264.7 murine macrophages. Materials and methods: RAW 264.7 cells were pretreated with 2.5, 5, or 12.5 mu g/ml of taraxasterol 1 h prior to treatment with 1 mu g/ml of LPS. Nitric oxide (NO) level in supernatants from cells was examined by Griess reaction, the concentrations of prostaglandin E-2 (PGE(2)), tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) were measured by ELISA. Nuclear factor kappa B (NF-kappa B) activation was evaluated by immunocytochemical analysis. Results: We found that taraxasterol inhibited NO, PGE2,TNF-alpha, IL-1 beta and IL-6 production in LPS-induced RAW 264.7 macrophages in a dose-dependent manner. Further studies revealed that taraxasterol prevented the LPS-induced NF-kappa B translocation from cytoplasm into nuclear. Conclusions: These results indicate that taraxasterol has anti-inflammatory effect by blocking NF-kappa B pathway. (C) 2012 Elsevier Ireland Ltd. All rights reserved.