Sustainable fabrication of silver and copper-doped silver nanoparticles using Melia azedarach for antimicrobial and antioxidant applications

Green nanotechnology offers a sustainable method for synthesizing silver nanoparticles (AgNPs) and copper-doped silver nanoparticles (Cu-AgNPs) using the aqueous extract of Melia azedarach leaves. The biosynthesized NPs were characterized using multiple analytical techniques, including UV–Visible spectroscopy, FTIR, XRD, TEM, SEM, and EDS. UV–Vis spectra exhibited peaks at 548 nm for AgNPs and 652 nm for Cu-AgNPs. XRD results revealed a face-centered cubic (FCC) crystal structure with crystallite sizes of AgNPs (17.66 nm) and Cu-AgNPs (8.97 nm). TEM analysis revealed irregular spherical morphology with average particle sizes of 57 ± 21 nm and 26 ± 8 nm for AgNPs and Cu-AgNPs, respectively. Both the synthesized NPs inhibited the growth of all tested bacterial strains. Cu-AgNPs showed the lowest MIC (125 ± 0 µg/mL) against B. subtilis and K. pneumoniae . AgNPs and Cu-AgNPs exhibited concentration-dependent activity in DPPH, ABTS, and FRAP assays. In the DPPH assay, AgNPs showed a low IC 50 (65.20 µg/mL) compared with the standard ascorbic acid (70.29 µg/mL). These findings suggest that M. azedarach -mediated AgNPs and Cu-AgNPs show promise; however, further studies are needed to validate their biomedical and pharmaceutical relevance.