Polyphenol-rich blue honeysuckle extract alleviates silica particle-induced inflammatory responses and macrophage apoptosis via NRF2/HO-1 and MAPK signaling

The blue honeysuckle is a rich source of bioactive compounds. In this study, we obtained a polyphenol-rich blue honeysuckle extract (BHE) and found that cyanidin 3-glucoside and chlorogenic acid accounted for most of its phenolic content. Administration of BHE to mice alleviated silica particle (SP)-induced lung inflammation and reduced the recruitment of macrophages to lungs. BHE also reduced the pro-inflammatory cytokine levels in the bronchoalveolar lavage fluid. In vitro study showed that BHE reduced pro-inflammatory cytokine secretion by macrophages and reduced apoptosis in macrophages. Cell signaling analysis revealed that BHE inhibited p38 and c-Jun N-terminal kinase phosphorylation and decreased the nuclear expression of nuclear factor-κB. BHE treatment also down-regulated the expression of inducible nitric oxide synthase and up-regulated two antioxidant mediators, nuclear factor (erythroid-derived 2)-like 2 and heme oxygenase-1, in macrophages. The findings demonstrated that BHE may serve as a complementary and alternative functional food to prevent SP-induced pulmonary diseases.