Biogenic synthesis of silver nanoparticles using Zaleya pentandra and investigation of their biological activities

This study reports a sustainable and eco-friendly approach for the green synthesis and optimization of silver nanoparticles (AgNPs) utilizing the Zaleya pentandra stem extract (ZSE). Critical reaction parameters including temperature (25 °C), pH (9.0), extract volume (200 µL), and incubation duration (24 h) were systematically optimized to enhance green-synthesized AgNPs yield. Successful synthesis of AgNPs was confirmed by UV-Vis spectroscopy, exhibiting a distinct surface plasmon resonance (SPR) peak at 426 nm. The FT-IR spectroscopy revealed phytochemical functional groups acting as bioreductants and capping agents. Morphological and structural characterizations using Field Emission Scanning Electron Microscope (FESEM) and XRD confirmed the formation of predominantly spherical nanoparticles, while EDX spectroscopy validated silver as pure element with minor contributions from plant-derived elements likely associated with phytochemical capping or sample preparation. The green-synthesized AgNPs displayed potent antibacterial efficacy, with inhibition zones of 30.9 mm (Staphylococcus aureus), 27.6 mm (Klebsiella pneumoniae), and 25.0 mm (Escherichia coli). In antifungal assays, the green-synthesized AgNPs achieved > 97% mycelial growth inhibition against a spectrum of phytopathogenic fungi. Antioxidant potential assessed via DPPH radical scavenging assay yielded a significant IC₅₀ value of 199.07 µg/mL for the green-synthesized AgNPs. Notably, the green-synthesized AgNPs exhibited strong α-glucosidase inhibitory activity (IC₅₀: 67.059 µg/mL), surpassing the efficacy of the standard drug acarbose (IC₅₀: 77.42 µg/mL).These multifunctional silver nanoparticles, synthesized via an optimized process and a green route using Z. pentandra stem extract demonstrated significant promise for applications in antimicrobial, antioxidant, and antidiabetic therapeutics, underscoring their potential role in next-generation nanomedicine.