Biofabrication of ZnO nanoparticles using Acacia arabica leaf extract and their antibiofilm and antioxidant potential against foodborne pathogens

PLoS One. 2022 Jan 5;17(1):e0259190. doi: 10.1371/journal.pone.0259190. eCollection 2022.

Abstract

Emergence of multidrug resistant pathogens is increasing globally at an alarming rate with a need to discover novel and effective methods to cope infections due to these pathogens. Green nanoparticles have gained attention to be used as efficient therapeutic agents because of their safety and reliability. In the present study, we prepared zinc oxide nanoparticles (ZnO NPs) from aqueous leaf extract of Acacia arabica. The nanoparticles produced were characterized through UV-Visible spectroscopy, scanning electron microscopy, and X-ray diffraction. In vitro antibacterial susceptibility testing against foodborne pathogens was done by agar well diffusion, growth kinetics and broth microdilution assays. Effect of ZnO NPs on biofilm formation (both qualitatively and quantitatively) and exopolysaccharide (EPS) production was also determined. Antioxidant potential of green synthesized nanoparticles was detected by DPPH radical scavenging assay. The cytotoxicity studies of nanoparticles were also performed against HeLa cell lines. The results revealed that diameter of zones of inhibition against foodborne pathogens was found to be 16-30 nm, whereas the values of MIC and MBC ranged between 31.25-62.5 μg/ml. Growth kinetics revealed nanoparticles bactericidal potential after 3 hours incubation at 2 × MIC for E. coli while for S. aureus and S. enterica reached after 2 hours of incubation at 2 × MIC, 4 × MIC, and 8 × MIC. 32.5-71.0% inhibition was observed for biofilm formation. Almost 50.6-65.1% (wet weight) and 44.6-57.8% (dry weight) of EPS production was decreased after treatment with sub-inhibitory concentrations of nanoparticles. Radical scavenging potential of nanoparticles increased in a dose dependent manner and value ranged from 19.25 to 73.15%. Whereas cytotoxicity studies revealed non-toxic nature of nanoparticles at the concentrations tested. The present study suggests that green synthesized ZnO NPs can substitute chemical drugs against antibiotic resistant foodborne pathogens.

MeSH terms

  • Acacia / metabolism*
  • Anti-Bacterial Agents / pharmacology
  • Antioxidants / pharmacology
  • Biofilms / drug effects
  • Escherichia coli / drug effects
  • Foodborne Diseases / microbiology
  • Foodborne Diseases / prevention & control*
  • Green Chemistry Technology / methods
  • HeLa Cells
  • Humans
  • Metal Nanoparticles / chemistry*
  • Microbial Sensitivity Tests / methods
  • Microscopy, Electron, Scanning / methods
  • Plant Extracts / pharmacology
  • Plant Leaves / metabolism
  • Reproducibility of Results
  • Spectrometry, X-Ray Emission / methods
  • Staphylococcus aureus / drug effects
  • X-Ray Diffraction / methods
  • Zinc / chemistry
  • Zinc / metabolism
  • Zinc Oxide / chemistry*
  • Zinc Oxide / metabolism

Substances

  • Anti-Bacterial Agents
  • Antioxidants
  • Plant Extracts
  • Zinc
  • Zinc Oxide

Grants and funding

The researchers would like to thank the Deanship of Scientific Research, Qassim University for funding the publication of this project. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.