Phyto-Assisted Synthesis of Bio-Functionalized Ag/Ag2O Nanoparticles, Characterization, Optical and Their Potential Anti-Oxidants Activities

Abstract

In this study, green synthesis of silver/ silver oxide nanoparticles (Ag/Ag₂O NPs) was achieved by bio-reduction of silver nitrate using Mentha Piperita  plant leaves extract.The effect of different silver nitrate concentrations on the formation ofsilver nanoparticleswas studied. The obtained nanoparticles were characterized using UV-Vis, FT-IR, XRD, and SEM techniques. The antioxidant activity of samples was evaluated using three methods: the DPPH test (2,2-diphenyl-1-1-picrirylhydrazil), the FRAP (Ferric reducing antioxidant power)  and TAC (Total Antioxidant Capacity) test. UV-Vis spectra showed maximum absorption in the range of 253–300 nm related to the silver. FTIR spectra exhibit a weak peak at 565 cm^-1 attributed to silver NPs vibration, confirming the nanoparticles formation. The X-Ray Diffraction (XRD) analysis confirmed the crystalline nature of (Ag/Ag₂O NPs) with an average size ranged in 31–42 nm. SEM showed that the green synthesizing silver nanoparticles having in general as cubical shape. Among the examined extracts, (Ag/Ag₂O NPs)  with 1g concentration showed the highest antioxidant activity with value of  2.749, 21.60 and 18.69 mg/ml for DPPH, FRAP and TAC tests respectively. Consequently, the use of peppermint leaves extract offers a convenient, rapid, cost-effective, and environmentally friendly alternative to other methods. The research findings from the various assays measuring antioxidant capacity clearly demonstrate that the silver nanoparticles produced by M. Piperita possess potent natural antioxidant properties that are beneficial for preserving health.