Eco-friendly Synthesis, Characterization, and Biological Evaluation of Silver Nanoparticles from Verbascum uschakense Aqueous Extract.

Abstract

Silver nanoparticles synthesized using Verbascum uschakense extract at a reaction temperature of 60 °C were characterized through multiple analytical techniques. These included ultraviolet-visible absorption spectroscopy, X-ray diffraction analysis, high-resolution transmission electron microscopy, and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. Ultraviolet-visible spectral analysis revealed a surface plasmon resonance peak at 432 nanometers, indicating the successful formation of silver nanoparticles. Microscopic analyses demonstrated that the nanoparticles were predominantly spherical in shape, with particle sizes ranging between 4 and 14 nanometers. X-ray diffraction analysis confirmed that the silver nanoparticles possessed a face-centered cubic crystal structure, as evidenced by characteristic diffraction peaks at 2θ values of 38.21°, 44.46°, 64.59°, and 77.48°, corresponding to the (111), (200), (220), and (311) planes, respectively. Regarding the biological activities, the antioxidant capacity of the aqueous extract of V. uschakense was evaluated by its ability to scavenge free radicals. At a concentration of 1 milligram per milliliter, the extract demonstrated a 86.93 percent scavenging effect against the stable radical 2,2-diphenyl-1-picrylhydrazyl. In comparison, the silver nanoparticles synthesized from the plant extract exhibited a 60.04 percent scavenging effect at the same concentration. Additionally, the silver nanoparticles showed strong inhibition in the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay, with values comparable to those obtained using the standard antioxidant TroloxThe antimicrobial properties of the biosynthesized silver nanoparticles were examined using the disc diffusion method. The nanoparticles exhibited inhibitory activity against several pathogenic microorganisms, including Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes, and fungal species belonging to the Candida genus. These results highlight the potential of V. uschakense-mediated silver nanoparticles as multifunctional bioactive agents with both antioxidant and antimicrobial properties. The study demonstrates that green synthesis offers a sustainable and effective approach to producing nanomaterials with potential applications in biomedical and pharmaceutical fields.