A green approach to natural products mediated synthesis of nanomaterial using <i>Astragalus pennatulus</i> , characterization, biological effect, and quantification of phenolics

Nanotechnology has gained significant attention due to its wide range of applications in various industries. It is based on the development and study of the unique properties of nanoscale materials. This study describes the production of nanoparticle (a-AgNPs) using <i>Astragalus pennatula</i> leaves and evaluates their antioxidant activity <i>in vitro</i>. The absorption (UV-Vis) at 443 nm confirmed the establishment of the nanoparticles. SEM verified the morphology as spherical. XRD determined the particle size and crystal structure. The particle size was calculated to be 12.4 nm by the Scherrer equation. FTIR spectrum suggested the possible functional groups of molecules acting as reducing agents. The typical signal of the OH group was detected at 3271 cm^-1. TEM analysis revealed the morphology of the nanostructure, with a particle size of 9.1 nm. The EDX spectrum revealed an intense peak of silver at 3-3.5 eV, verifying the desired product. The elemental analysis presented the composition of the synthesized material. The zeta potential illustrated the stability of the synthesized material. The antioxidant potential of <i>A. pennatula</i> leaves and nanostructure was assessed. DPPH and ABTS activities of a-AgNPs were found to be (µg/mL) 12.6 and 3.3, respectively. Quantitative analysis resulted in the determination of chlorogenic acid, salicylic acid, hesperidin, rutin, and luteolin as major compounds.