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 12.5μg/ml of taraxasterol 1h prior to treatment with 1μg/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-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were measured by ELISA. Nuclear factor kappa B (NF-κB) activation was evaluated by immunocytochemical analysis.

Results: We found that taraxasterol inhibited NO, PGE(2), TNF-α, IL-1β 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-κB translocation from cytoplasm into nuclear.

Conclusions: These results indicate that taraxasterol has anti-inflammatory effect by blocking NF-κB pathway.