Silver nanoparticles synthesised by using Iranian Mentha pulegium leaf extract as a non-cytotoxic antibacterial agent

Silver nanoparticles (AgNPs) were biosynthesized using the aqueous extract ofMentha pulegium leaves and were characterized by Ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, Scanning electron microscopy, X-ray diffraction, Energy-dispersive X-ray spectroscopy, and X-ray fluorescence analysis. The bactericidal activity was assayed by disc diffusion and broth microdilution methods. The cytotoxicity was examined on normal human peripheral blood mononuclear cells (PBMCs) by MTT assay. SEM and XRD analysis showed the spherical and face-centered cubic nano silver particles with an average size of 29 nm. EDX and XRF spectra exhibited obvious signals in the silver region. The AgNPs displayed antibacterial activity against Staphylococcus aureus followed by Bacillus cereus, Klebsiella pneumoniae and Escherichia coli with minimum inhibitory concentrations (MICs) ranged from 61.5 to 125 mu g/mL. No significant cytotoxicity was observed against the PBMCs up to 250 mu g/mL of the AgNPs and hence the synthesized AgNPs may be used to treat drug-resistant bacteria in biomedicine.