Paeoniflorin Derivative in Paeoniae Radix Aqueous Extract Suppresses Alpha-Toxin of Staphylococcus aureus

The emergence and dissemination of bacterial infections is paralyzing our public health systems worldwide. Worse still, there are no effective antibiotics against bacterial toxins, which facilitate the infection. Natural herbs that target bacterial toxins may be a better choice for therapy of infectious diseases. However, most natural drugs present unknown compositions and unclear mechanisms. Here we demonstrated that the Chinese herb Paeoniae Radix aqueous extract (PRAE) could suppress alpha-toxin (alpha-toxin) of Staphylococcus aureus. We observed that the paeoniflorin derivative (PRAE-a) derivative in PRAE significantly abolished the hemolytic activity of S. aureus alpha-toxin. The analyses of high-performance liquid chromatography (HPLC), mass spectrometer (MS), Fourier transform infrared spectrometer (FTIR), and nuclear magnetic resonance (NMR) showed that PRAE-a was a glycoside compound with a paeoniflorin nucleus. We further found that PRAE-a disrupted the pore-forming ability of alpha-toxin by prevention of the dimer to heptamer. Therefore, PRAE-a proved to be an effective therapy for S. aureus lung infections in mice by inhibiting alpha-toxin. Collectively, these results highlighted that PRAE-a can be used as an antibacterial agent to attenuate S. aureus virulence by targeting alpha-toxin.

Automated summary

The study found that the paeoniflorin derivative (PRAE-a) in Paeoniae Radix aqueous extract can effectively inhibit the production of alpha-toxin by Staphylococcus aureus, providing a potential treatment option for lung infections.