Eco-Friendly Synthesis of Silver Nanoparticles Using Lespedeza capitata Extract: Antioxidant and Anti-Inflammatory Properties in Zebrafish (Danio rerio)

Silver nanoparticles (AgNPs) were synthesized using a modified literature method involving aqueous AgNO₃ (3 mM) and plant extract (LCE) at a constant ratio, under alkaline conditions and controlled temperature. The nanoparticles were characterized by UV-Vis spectroscopy, dynamic light scattering (DLS), zeta potential analysis and scanning transmission electron microscopy (STEM). The UV-Vis spectra displayed a broad absorption band around 450 nm, indicative of polydispersity, while DLS revealed a hydrodynamic diameter of 90.3 nm with a polydispersity index of 0.3366. Zeta potential values suggested reduced electrostatic stability compared with previously reported plant-derived AgNPs, although STEM images confirmed predominantly spherical, well-dispersed nanoparticles with sizes between 15 and 20 nm. Functional assays in zebrafish demonstrated the biological relevance of AgNPs. In scopolamine-induced models of cognitive and behavioral deficits, AgNPs treatment significantly improved memory and locomotor activity, as assessed by the Y-Maze, Novel Tank Diving Test and Novel Object Recognition Test.