Background: Recently, there has been a lot of interest in environmentally friendly nanoparticle synthesis

Silver nanoparticles (AgNPs) are promising against antibiotic resistance due to their high surface energy, robust action, and excellent adsorbability

Aim: The primary objective of this study was to assess the antibacterial efficacy of AgNPs that were manufactured using three environmentally friendly methods (lemon, Streptomyces, and chitosan)

Furthermore, the study attempted to investigate the potential toxicity of these nanoparticles on mice

Methods: The synthesis of AgNPs was characterized by XRD, TEM FTIR, and TGA

The antimicrobial effect of AgNPs was studied using the disc diffusion method and minimum inhibitory concentration (MIC)

The antibacterial mechanism of AgNPs was determined using different methods, such as released glucose and proteins, respiratory chain inhibition, plasma membrane fluorescence anisotropy, DNA fragmentation, gel electrophoresis, and cell membrane potential

Results: The TEM analysis of Ag NPs showed predominantly spherical particles with a size distribution of 10-60 nm

AgNPs synthesized by the three green methods showed antibacterial and fungal activity

The antibacterial mechanisms of AgNPs involved inhibition of LDH activity, increased protein and glucose leakage, DNA and protein damage, and depolarization and destabilization of the plasma membrane

AgNPs, on the other hand, increased alanine aminotransferase, aspartate aminotransferase, urea, creatinine, malondialdehyde, and nitric oxide levels in mice while decreasing glutathione reduced

Conclusion: Our study showed that AgNPs synthesized by Streptomyces, lemon, and chitosan have powerful antimicrobial properties

Chitosan-AgNPs showed the most pronounced antibacterial action, although it displayed significant toxicity in mice

Conversely, lemon-AgNPs revealed the least notable impact.