Diosmetin inhibits the expression of alpha-hemolysin in Staphylococcus aureus

Staphylococcus aureus is a significant human pathogen that causes a wide range of diseases. Alpha-hemolysin (Hla), a pore-forming cytotoxin that is produced by most S. aureus strains, can cause tissue injury and plays a critical role in the virulence of this pathogen. In the present study, we discovered that diosmetin, a natural flavonoid that occurs primarily in citrus fruits and exhibits little anti-S. aureus activity, could diminish the production of Hla in culture supernatants in a concentration-dependent manner. The analysis of cytotoxicity in the co-culture system of S. aureus and A549 epithelial cells showed that such inhibition confers significant protection against S. aureus-mediated injury. Our results suggested that diosmetin has the potential to be a new anti-virulence drug for S. aureus infection, particularly for the targeting of Hla.