Antibacterial Activity and Biofilm Inhibition of Gold Nanoparticles Synthesized with Ethanolic Extract of Rosa damascena and Juglans regia

Background and purpose: This study aimed at investigating the antibacterial effects of nanoparticles synthesized with ethanol extract of Rosa damascena and Juglans regia (walnut leaves) against methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii. Materials and methods: In this experimental study, gold nanoparticles were synthesized by green method using ethanol extract of R. damascena and walnut leaves. Then, inhibition of biofilm formation, minimum growth inhibitory concentration (MIC), and minimum bacterial lethal concentration (MBC) were determined by micro broth dilution method. Also, inhibition of biofilm synthesis by nanoparticles was investigated against methicillin-resistant S. aureus, P. aeruginosa, and A. baumannii. Results: UV-vis spectroscopy showed that the gold nanoparticles synthesized with the ethanolic extract of R. damascena had better quality than the nanoparticles synthesized with the ethanolic extract of walnut leaf in terms of uniformity and ease of synthesis. The greatest effect of gold nanoparticle synthesized with ethanolic extract of R. damascena was on bacterial biofilm formed by Methicillin-resistant S. aureus, which inhibited the biofilm of this bacteria by 100%. Conclusion: In this study, nanoparticles synthesized with ethanolic extract of R. damascena showed higher antibacterial properties than walnut leaves. These findings can provide the basis for further in vivo studies to identify, quantify and purify its effective compounds.