The impact of flavonoids-rich Ziziphus jujuba Mill. Extract on Staphylococcus aureus biofilm formation

Background: To evaluate the in vitro antibacterial effect of flavonoids-rich Ziziphus jujuba Mill. extract (FZM) against the formation of bacterial biofilms (BBFs) in Staphylococcus aureus.

Results: FZM can effectively inhibit the formation of S. aureus biofilms in vitro. Morphological observation showed a decrease in both biofilm adhesion and thickness. Results of confocal laser scanning microscopy used to detect the thickness of the BBFs showed that FZM treatment reduced the thickness of the BBFs. Furthermore, after the Image-Pro Plus v.6.0 analysis of the fluorescence intensity, FZM treatment reduced the thickness of the BBFs as well as the proportion of green fluorescence. Scanning electron microscopy showed that FZM can disrupt the channels available for substance exchange in the biofilm, thus exposing the bacterial cells and damaging its three-dimensional structures.

Conclusion: FZM can inhibit biofilm formation, improve the bacterial pH environment, and eliminate the hydrophobic effect of reactive oxygen species and flavonoids.

Keywords: Bacterial biofilm; Confocal laser scanning microscope; Crystal violet assays; Flavonoids-rich Ziziphus jujuba mill. Extract; Scanning electron microscope; Staphylococcus aureus.