Antibacterial efficacy of green synthesized silver nanoparticles from rosemary, pennyroyal, and eucalyptus extracts against E. coli and S. aureus bacteria

Bacteria, including those causing hospital-acquired infections, have become a significant concern for human health due to their resistance to common antibiotics. Silver nanoparticles possess highly antimicrobial properties and can be applied in various medical and healthcare contexts. The purpose of this research is to produce silver nanoparticles through a bio-based (green synthesis) method using extracts from the leaves of rosemary, pennyroyal, and eucalyptus plants and to investigate their antibacterial activity. Extracts from the leaves of rosemary, pennyroyal, and eucalyptus plants were prepared and added to a silver nitrate solution in the process of synthesizing silver nanoparticles. The production of silver nanoparticles in the solution was investigated by recording the color changes during the experiment and measuring the absorption levels across different wavelengths using a spectrophotometer. The antimicrobial effects exhibited by the silver nanoparticle solution were investigated and confirmed targeting both Staphylococcus aureus and Escherichia coli (E. coli) strains using the agar well diffusion method. Nanoparticles with diameters approximately ranging from 18 to 80 nanometers were successfully synthesized, exhibiting a varied assortment of spherical geometries and a notable purity level of 88% silver. Furthermore, nanoparticles synthesized from rosemary plant extract exhibited superior antibacterial properties compared to those from other plant extracts.