RSM-CCD Optimized Green Synthesis of Quercus suber-Mediated Silver Nanoparticles: Comprehensive Characterization and Potent Antioxidant, Antimicrobial, and Anticancer Activities Against MCF-7 Cells

Abstract This article reports a green synthesis of silver nanoparticles (AgNPs) by a hydroalcoholic extract obtained from aerial parts of Quercus suber L. collected from the Beni Ali region, northern Algeria. By varying sonication time, ultrasonic amplitude, and extract concentration using response surface methodology with central composite design, we optimized the biosynthesis process for maximum nanoparticle formation efficiency. AgNPs were fully characterized using ultraviolet-visible (UV-Vis) spectroscopy, dynamic light scattering (DLS), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) analysis, thermogravimetric analysis (TGA), and zeta potential measurements to confirm their preliminary physical composition. The analyses confirmed that crystalline and functionalized nanoparticles with the average size of 64.34 nm demonstrated thermal stability throughout the synthesis procedure. AgNPs capped with Q. suber extract showed significant activities in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays, which indicated that they had potent free radical scavenging and ferric-reducing abilities. Antimicrobial assays showed AgNPs’ inhibition zones were larger than those of plant extract and silver nitrate samples against gram-positive and gram-negative bacteria and fungal strains. A dose-dependent cytotoxic effect was observed on the MCF-7 human breast adenocarcinoma cells, with a half maximal inhibitory concentration IC50 of 122.25 μg/mL, suggesting moderate toxicity and potential therapeutic application. Q. suber-mediated green synthesis of AgNPs has shown potential as an environmentally friendly and easy method. This study sets the stage for in vivo exploration of these biogenic nanoparticles for both therapeutic and environmental applications.