Hypericum ascyron L. extract reduces particulate matter‐induced airway inflammation in mice

The consequences of increased industrialization increased the risk of asthma and breathing difficulties due to increased particulate matter in the air. We aim to investigate the therapeutic properties of Hypericum ascyron L. extract (HAE) in airway inflammation and unravel its mechanism of action. We conducted nitric oxide and cell viability assay, real‐time PCR and western blot analyses along with in vitro studies. in vivo studies include a model of coal fly ash and diesel exhaust particle (CFD)‐induced airway inflammation in mice. HAE reduced coal fly ash (CFA)‐induced nitric oxide secretion without exhibiting cytotoxicity in MH‐S cells. HAE also reduced the mRNA expression of pro‐inflammatory cytokines and reduced the expression of proteins in the NFκB and MAPK pathways. In a mice model of CFD‐induced airway inflammation, HAE effectively reduced neutrophil infiltration in bronchoalveolar lavage fluid (BALF) and increased the amount of T cells in the BALF, lungs, and blood while reducing all other immune cell subtypes to reduce airway inflammatory response. CXCL‐1, IL‐17, MIP‐2, and TNF‐α expression in the BALF were also reduced. HAE effectively reduced MIP‐2 and TNF‐α mRNA expression in the lung tissue of mice. In a nutshell, HAE is effective in preventing airway inflammation induced by CFA in MH‐S cells, as well as inflammation induced by CFD in mice.