Inhibitory Effects of Ginkgo biloba Extract on Inflammatory Mediator Production by Porphyromonas gingivalis Lipopolysaccharide in Murine Macrophages via Nrf-2 Mediated Heme Oxygenase-1 Signaling Pathways

Periodontitis is an oral chronic inflammatory disease that influences systemic diseases. Heme oxygenase-1 has several beneficial abilities through Nrf-2 regulation. Ginkgo biloba has been reported to have anti-inflammatory effects associated with heme oxygenase-1 (HO-1) expression. In this study, we investigated whether the anti-inflammatory effects of G. biloba were involved with Nrf-2-mediated HO-1 expression in Porphyromonas gingivalis LPS-stimulated RAW264.7 macrophage cells. G. biloba was extracted with ethyl acetate (EGB). EGB exhibited anti-inflammatory activities, which suppressed the production of pro-inflammatory mediators, the activation of mitogen-activated protein kinases, and nuclear translocation of transcription factors. EGB also up-regulated the HO-1 expression, and the Nrf-2 level in the nucleus and its transactivity. Furthermore, reduced pro-inflammatory mediator levels by EGB were inverted in the presence of SnPP. The collective results suggest that the anti-inflammatory effects of EGB are due to the HO-1 expression via up-regulation of Nrf-2 in RAW 264.7 cells stimulated by P. gingivalis LPS.