Plant extract-mediated synthesis of Ag/Ag₂O nanoparticles using Olea europaea leaf extract: assessing antioxidant, antibacterial, and toxicological properties

Plant extract-mediated synthesis has the advantage of being simple, cost-effective, and environmentally friendly. In this study, we synthesized silver/silver oxide nanoparticles (Ag/Ag2O NPs) using an aqueous Olea Europaea leaf extract as a reducing and stabilizing agent. The Ag/Ag2O NPs were synthesized and the plant extract was processed using only pure water, without the use of any harmful reagents or organic solvents. The synthesized Ag/Ag2O NPs exhibited a spherical morphology with a particle size of 45 nm, and an average crystallite size of 24 nm for the Ag phase and 26 nm for the Ag2O phase. The optical band gap energy of the Ag/Ag2O NPs was calculated to be 2.23 eV. The antimicrobial and antioxidant activities of the Ag/Ag2O NPs were then investigated. The Ag/Ag2O NPs exhibited potent antimicrobial activity against Escherichia coli (E.coli), Staphylococcus aureus (Sa), and Pseudomonas aeruginosa (Pa) at concentrations of 50-200 mu g/mL, with the highest activity observed at a concentration of 200 mu g/mL, respectively. Moreover, Ag/Ag2O NPs at a concentration of 2.5 mg/kg body weight during a 28-day study in adult male rats (10-11 weeks old) showed remarkable antioxidant activity and no acute toxicity when administered at different doses of Ag/Ag2O NPs (2.5 and 5 mg/kg body weight). The most effective antioxidant exhibited an IC50 value of 7.043 +/- 1.352 mu g/ml, a FRAP value of 445.34 +/- 7.90 mg E FeSO4/g NPs, and a TAC value of 67.72 +/- 2.38 mg E GA/g NPs, indicating it's ferric reducing antioxidant power (FRAP) and total antioxidant capacity (TAC). Accordingly, the developed Ag/Ag2O NPs can be used as chemotherapeutic drug carriers for antioxidant and antibacterial applications.