Microwave-assisted phytogenic Ag/Ag2O/ZnO nanocomposite as replacement of Ag/Ag2O and ZnO nanoparticles: A comparative antioxidant study

A biogenic approach, particularly plant-mediated synthesis, is currently regarded as the sustainable approach for synthesizing nanomaterials (NMs). The present investigation concentrates on the green fabrication of Ag/Ag2O nanoparticles (NPs), ZnO NPs, and Ag/Ag2O/ZnO nanocomposites (NCs) via microwave irradiation using Murusi peel (MP) and Kew peel (KP) aqueous extracts and comparatively determine their antioxidant potentials. The synthesis parameters of Ag/Ag2O NPs, ZnO NPs, and Ag/Ag2O/ZnO NCs were optimized and characterized using different analytical techniques. Surface plasmon resonance peaks appeared at 448-450 nm, 350-370 nm, and 400-500 nm for Ag/Ag2O NPs, ZnO NPs, and Ag/Ag2O/ZnO NCs, respectively. The scanning electron micro-scopic images of both peel-mediated Ag/Ag2O NPs depicted quasi-spherical shapes aggregating on the flake -shaped ZnO surface, leading to the Ag/Ag2O/ZnO NCs formation. Transition electron microscopic analysis revealed the average particle sizes of MP and KP-mediated Ag/Ag2O NPs, ZnO NPs, and Ag/Ag2O/ZnO NCs as 13.58 +/- 1.32 nm, and 36.79 +/- 1.24 nm, 13.00 +/- 1.26 nm, and 10.28 +/- 1.25 nm, 28.37 +/- 1.39 nm, and 11.21 +/- 1.06 nm, respectively. X-ray diffraction analysis confirmed the synthesis of pure crystalline structures with a hex-agonal wurtzite structure for ZnO and a face-centered structure for Ag and Ag2O during the formation of Ag/ Ag2O/ZnO NCs. According to the research findings, MP and KP-mediated Ag/Ag2O/ZnO NCs displayed an enhanced free radical scavenging effect for DPPH (2,2-diphenyl-1-picrylhydrazyl) assay with IC50 values of 54.13 +/- 0.53 ppm and 51.41 +/- 1.27 ppm, respectively. At higher concentrations, the NCs exhibited a greater radical scavenging potential for ABTS (2,2 '-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) assay, with the IC50 values for MP and KP-mediated as 72.28 +/- 0.83 ppm and 65.78 +/- 1.29 ppm, respectively. Similarly, for the FRAP (Ferric reducing antioxidant power) assay, MP and KP-mediated Ag/Ag2O/ZnO NCs demonstrated a higher antioxidant potential, expressed in terms of ascorbic acid equivalents (AE), which were 46 +/- 0.7 (AE) mg/1 g and 50 +/- 1.1 (AE) mg/1 g, respectively. To the best of our knowledge, this study remains the first comparative analysis of syner-gistically enhanced antioxidant potential of the agro-waste mediated Ag/Ag2O/ZnO NCs with their respective NPs counterparts, Ag/Ag2O NPs and ZnO NPs. These research findings pave the path for sustainably utilizing these NMs in biomedical applications.

Automated summary

The study focuses on the green fabrication of Ag/Ag2O nanoparticles, ZnO nanoparticles, and Ag/Ag2O/ZnO nanocomposites using Murusi peel and Kew peel extracts. The synthesized nanomaterials were characterized and their antioxidant potentials were evaluated. The results showed that the Ag/Ag2O/ZnO nanocomposites exhibited enhanced antioxidant activity compared to their counterparts.