Chrysin protects mice from Staphylococcus aureus pneumonia

Aim:  To elucidate the effect of chrysin on α‐haemolysin production by Staphylococcus aureus and protection against pneumonia in a murine model. Methods and Results:  Haemolysis, Western blot and real‐time RT‐PCR assays were performed to evaluate the effect of chrysin on α‐haemolysin secretion by Staph. aureus . The efficacy of chrysin against human alveolar epithelial cell injury by α‐haemolysin was tested using live/dead staining or by measuring lactate dehydrogenase activity. Furthermore, we determined the protective effect of chrysin against Staph. aureus pneumonia through histopathology experiments in a mouse model. The production of α‐haemolysin by Staph. aureus was inhibited when presented with an increasing subinhibitory concentration of chrysin in vitro . Consistent with this result, chrysin prevented α‐haemolysin‐mediated cell injury and protected mice from Staph. aureus pneumonia. Conclusions:  Chrysin is a potent inhibitor of α‐haemolysin expression by Staph. aureus , and it conferred a significant degree of protection against Staph. aureus pneumonia. Significance and Impact of Study:  The chrysin‐mediated inhibition of α‐haemolysin production and protection against Staph. aureus pneumonia may offer a new strategy in combating pathogen infections.