Silver nanoparticles production mediated by natural tetraploid Trifolium pratense L.: Characterization and potential biological activity

This study was aimed to present the green synthesis of silver nanoparticles through natural tetraploid Trifolium pratense L. containing high amounts of phenolic compounds and glycosidic bioactive macromolecules. Combinatorial optimization of AgNPs was achieved thanks to the stabilizing and reducing properties of the natural tetraploid T. pratense L. flowering herb extract. The biologically synthesized AgNPs were visualized by color change in UV–Vis spectroscopy. UV–Vis spectroscopy proved to be a fast and simple method to determine the synthesis of AgNPs. In addition, TEM, XRD, and FTIR analyses were performed to confirm and characterize the formation of crystalline silver nanoparticles. It was shown by the TEM analysis that AgNPs changed their size and shape when biosynthesized in different conditions. It was determined that smaller AgNPs were spherical and larger AgNPs had a truncated octahedron shape. The XRD analysis proved the presence of Ag0 in nanoparticles and showed its crystal structure and faced cubic shapes for AgNPs. Interactions between the plant bioactive compounds and the AgNPs were distinctly visible in the FTIR spectra. The biosynthesized AgNPs showed strong antioxidant activity against DPPH and ABTS; furthermore, the total phenol content was also high.