ABSTRACT
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-1ß (IL-1ß) 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-1ß 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.
Subject(s)
Anti-Inflammatory Agents/pharmacology , Drugs, Chinese Herbal/pharmacology , Lipopolysaccharides/pharmacology , Macrophages/drug effects , Sterols/pharmacology , Triterpenes/pharmacology , Animals , Cell Line , Cell Survival/drug effects , Dinoprostone/metabolism , Dose-Response Relationship, Drug , Enzyme-Linked Immunosorbent Assay , Immunohistochemistry , Inflammation Mediators/metabolism , Interleukin-1beta/metabolism , Interleukin-6/metabolism , Macrophages/immunology , Macrophages/metabolism , Mice , NF-kappa B/antagonists & inhibitors , NF-kappa B/metabolism , Nitric Oxide/metabolism , Phytotherapy , Plants, Medicinal , Signal Transduction/drug effects , Tumor Necrosis Factor-alpha/metabolismABSTRACT
AIM OF THE STUDY: Taraxacum officinale has been frequently used as a remedy for inflammatory diseases. In the present study, we investigated the in vivo protective effect of Taraxacum officinale on acute lung injury (ALI) induced by lipopolysaccharide (LPS) in mice. MATERIALS AND METHODS: Taraxacum officinale at 2.5, 5 and 10 mg/kg was orally administered once per day for 5 days consecutively, followed by 500 microg/kg LPS was instilled intranasally. The lung wet/dry weight (W/D) ratio, protein concentration and the number of inflammatory cells in bronchoalveolar lavage fluid (BALF) were determined. Superoxidase dismutase (SOD) and myeloperoxidase (MPO) activities, and histological change in the lungs were examined. The levels of inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in the BALF were measured using ELISA. RESULTS: We found that Taraxacum officinale decreased the lung W/D ratio, protein concentration and the number of neutrophils in the BALF at 24 h after LPS challenge. Taraxacum officinale decreased LPS-induced MPO activity and increased SOD activity in the lungs. In addition, histopathological examination indicated that Taraxacum officinale attenuated tissue injury of the lungs in LPS-induced ALI. Furthermore, Taraxacum officinale also inhibited the production of inflammatory cytokines TNF-alpha and IL-6 in the BALF at 6h after LPS challenge in a dose-dependent manner. CONCLUSIONS: These results suggest that Taraxacum officinale protects against LPS-induced ALI in mice.
