Inhibitory effects of various plant polyphenols on the toxicity of Staphylococcal α-toxin

Staphylococcal α-toxin, known for its wide spectrum of biological activities, is involved in the pathogenesis of Staphylococcal infectious diseases. In recent years, various phytochemicals have been found to have antimicrobiological, including antibacterial, antiviral and antifungal, and antitoxic activities. We investigated whether several plant polyphenols inhibit α-toxin activities in vitro and in vivo. We found hop bract tannin (HBT) and apple condensed tannin (ACT) to exert inhibitory effects on α-toxin cytotoxicity. HBT also reduced the murine skin inflammatory effect and the lethality of α-toxin. These polyphenols formed aggregates with α-toxin and thereby inhibited its activities. Inhibition of α-toxin by HBT and ACT was dose dependent, suggesting that these polyphenols may be a useful adjunct to current treatments for α-toxin catalyzed Staphylococcal infectious diseases.