Green Synthesis of Silver Nanoparticles Using Azadirachta indica Leaf Extract: Optimization, Characterization, and Agricultural Applications

Abstract

This study explores the green synthesis of silver nanoparticles (Ag NPs) using Azadirachta indica leaf extract as a reducing agent. Various physiochemical parameters such as pH, temperature, stirring time, and silver nitrate concentration were optimized to enhance Ag NPs formation. The synthesized Ag NPs were characterized by visual inspection and UV/Visible spectrophotometric analysis, revealing a maximum wavelength of 400-430nm. The average size of Ag NPs was determined to be 102.5nm. The Ag NPs exhibited efficient pesticidal potential against Rhyzopertha dominica and Tribolium castaneum, with increased mortality rates observed with higher concentrations. Additionally, the antimicrobial activity of Ag NPs was evaluated, showing stronger inhibition zones against gram-negative bacteria compared to gram-positive bacteria. Furthermore, the antifungal activity against Aspergillus niger, Aspergillus sojae, and Aspergillus flavus was demonstrated, with increased activity observed with higher concentrations of Ag NPs and plant extract. Overall, this study highlights the potential of nanobiopesticides synthesized from A. indica leaf extract as effective and cost-efficient tools for crop pest management.