Biosynthesis of silver nanoparticles using mobe (Artocarpus lakoocha Roxb) leaf aqueous extracts and their potential as antioxidant and antibacterial agents

Plant-mediated synthesis of nanoparticles has attracted increasing attention due to its environmentally friendly approach and the use of natural bioactive compounds as reducing agents. This study aimed to synthesize silver nanoparticles (AgNPs) using the aqueous leaf extract of Artocarpus lakoocha Roxb. with the assistance of microwave irradiation and to evaluate their antibacterial and antioxidant activities. The formation of AgNPs occurred through the reduction of Ag⁺ to Ag⁰ by biomolecules present in the extract. The synthesized nanoparticles were characterized using Ultraviolet–Visible spectroscopy (λ = 413 nm), Particle Size Analysis (66.83 nm), Fourier Transform Infrared spectroscopy, indicating the presence of O–H, C–O, C–H, CH₃, and C O functional groups, Scanning Electron Microscopy showing particle agglomeration, Energy Dispersive X-ray Spectroscopy with a dominant Ag composition of 89.6%, X-ray Diffraction confirming a face-centered cubic crystal structure with Miller indices (111), (200), (311), and (222), Transmission Electron Microscopy, and zeta potential analysis (−2.3 mV). Antibacterial testing against Staphylococcus aureus and Staphylococcus epidermidis showed Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values of 62.5 µg/mL and 125 µg/mL, respectively, indicating higher antibacterial activity of AgNPs compared to the aqueous extract. Antioxidant activity evaluated using the DPPH method revealed that AgNPs exhibited lower antioxidant activity, with an IC₅₀ value of 389.35 ± 2.25 µg/mL. These results highlight the potential of Artocarpus lakoocha Roxb. leaf aqueous extract as a bioreducing agent for microwave-assisted green synthesis of AgNPs, although further optimization is required to improve nanoparticle stability.