Antibacterial Activity of Juglone Revealed in a Wound Model of Staphylococcus aureus Infection

A serious problem currently facing the field of wound healing is bacterial infection, especially Staphylococcus aureus (S. aureus) infection. Although the application of antibiotics has achieved good effects, their irregular use has resulted in the emergence of drug-resistant strains. It is thus the purpose of this study to analyze whether the naturally extracted phenolic compound, juglone, can inhibit S. aureus in wound infection. The results show that the minimum inhibitory concentration (MIC) of juglone against S. aureus was 1000 μg/mL. Juglone inhibited the growth of S. aureus by inhibiting membrane integrity and causing protein leakage. At sub-inhibitory concentrations, juglone inhibited biofilm formation, the expression of α-hemolysin, the hemolytic activity, and the production of proteases and lipases of S. aureus. When applied to infected wounds in Kunming mice, juglone (50 μL juglone with a concentration of 1000 μg/mL) significantly inhibited the number of S. aureus and had a significant inhibitory effect on the expression of inflammatory mediators (TNF-α, IL-6 and IL-1β). Moreover, the juglone-treated group promoted wound healing. At the same time, in animal toxicity experiments, juglone had no obvious toxic effects on the main tissues and organs of mice, indicating that juglone has good biocompatibility and has the potential to be used in the treatment of wounds infected with S. aureus.