Investigation of the interaction between phloretin and Staphylococcus aureus toxin proteins and its application in...

This study investigated the inhibitory mechanisms of phloretin against S. aureus virulence protein (SEB and Hla), alongside evaluating its potential for food applications. Spectral analysis confirmed static quenching and spontaneous binding (hydrogen bonds, van der Waals) of phloretin to both toxins, inducing local hydrophobization in SEB and backbone expansion with polarity increase in Hla. FT-IR and CD analysis revealed that phloretin reduced α-helix and increased β-sheet content in Hla, disrupting its functional structure. Molecular docking revealed that phloretin might bind to the key flexible loop of SEB, hindering its recognition by host cells, and targeted the stem domain of Hla, thereby inhibiting its conformational transition and pore-forming activity. In cooked chicken, phloretin effectively suppressed toxin activity while also retarding lipid oxidation and protein degradation. This research elucidated the direct molecular mechanism of phloretin as a natural toxin inhibitor and provided a theoretical foundation for its application in meat preservation.