Phytosynthesis of silver nanoparticles with the aqueous extract of portulaca oleracea and its antimicrobial and antioxidant effect against gram-positive and gram-negative bacteria

Background: Due to the importance of investigating nosocomial infections and drug resistance in bacteria causing these infections, the use of herbs can be very helpful in treatment. In the present study, the effect of silver nanoparticles obtained from portulaca oleracea extract on bacteria causing nosocomial infections and effective parameters in the synthesis of these nanoparticles were investigated. Materials and methods: First, an aqueous extract of portulaca oleracea was added to a 1 mM silver nitrate solution. The extract was used as a reducing and stabilizing agent for nanoparticles. The effect of effective parameters for the optimization of silver nanoparticles was evaluated by ultraviolet-visible spectroscopy and transmission electron microscopy. The antioxidant and antibacterial effect of the synthesized nanoparticles was determined by studying the activity of catalase, MIC, MBC, disk, and well method. Results: The results showed the effect of alkaline pH as well as silver salt concentration on the quality of synthesized nanoparticles. Also, the results of the antimicrobial test showed that gram-negative bacteria revealed significant sensitivity to synthetic nanoparticles and Staphylococcus aureus showed the highest resistance to nanoparticles. Antioxidant properties were also observed against gram-negative strains. Conclusion: The results showed that silver nanoparticles synthesized with portulaca oleracea had antibacterial and antioxidant properties. Therefore, photosynthesis of nanoparticles can be a good option for the treatment of infectious diseases caused by gram-negative bacteria.