Anti-inflammatory activity of Bambusae Caulis in Taeniam through heme oxygenase-1 expression via Nrf-2 and p38 MAPK signaling in macrophages

Recently, it has been reported that several natural extracts have anti-inflammatory effects through HO-1 induction. In this study, we used the ethyl acetate fraction of Bambusae Caulis in Taeniam (BCE) to investigate its anti-inflammatory effect on macrophages stimulated with LPS from Porphyromonas gingivalis. BCE inhibited the production of pro-inflammatory cytokines in P. gingivalis LPS-stimulated RAW264.7 cells. BCE also suppressed the nuclear translocation of NF-κB and AP-1. A selective inhibitor of HO-1 attenuated BCE's inhibitory effects on the production of pro-inflammatory cytokines. BCE also dose-dependently increased HO-1 expression at both the mRNA and the protein levels. BCE increased nuclear translocation of Nrf-2. Finally, a specific inhibitor of p38 reduced BCE-induced HO-1 expression and BCE-induced phosphorylation of p38 MAPK. BCE induced anti-inflammatory effects by activating Nrf-2-mediated HO-1 induction via p38 signaling in P. gingivalis LPS-stimulated macrophages. This result indicates that BCE is a promising therapeutic agent for combating periodontitis.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► BCE, the ethyl acetate fraction of Bambusae Caulis in Taeniam demonstrated for anti-inflammatory activity in Porphyromonas gingivalis LPS-stimulated Macrophages. ► BCE induces HO-1 expression through regulating Nrf-2 in macrophages. ► p38 MAPK signaling arbitrates BCE-induced HO-1 expression. ► BCE exerts its anti-inflammatory effect via modulating p38/nrf-2/HO-1 signaling pathways.