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 μg/mL, with the highest activity observed at a concentration of 200 μg/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 µg/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.