The stems of Dendrobium huoshanense have long been used to prevent various diseases, including inflammatory diseases. This study was aimed to explain the anti-inflammatory effect of D. huoshanense stems in LPS-induced RAW 264.7 macrophages and to discover potential anti-inflammatory compounds. Results exhibited that D. huoshanense stems ethanol extract could significantly inhibit LPS-induced production of NO, TNF-α and IL-1β. Based on bioassay guided strategy, four bibenzyls (1-4) were isolated from D. huoshanense stems for the first time. Anti-inflammatory assay showed 1-4 could remarkably inhibit the production of NO in LPS-induced macrophages. Moreover, quantitative RT-PCR analysis displayed that the mRNA levels of iNOs, TNF-α and IL-1β could also be significantly reduced by 1-4. These results suggested that D. huoshanense stems ethanol extract and bibenzyls 1-4 might be well developed as therapeutic agent to prevent inflammatory diseases.
Keywords: Dendrobium huoshanense; anti-inflammation; bibenzyls; bioassay guided; macrophages.