Green biosynthesis of silver nanoparticles using leaf extract of Ammannia baccifera for evaluating their antioxidant, antibacterial and catalytic potentials

The objective of this work is to create an easy, economical, and environmentally sustainable process for making silver nanoparticles (AB-AgNPs) by employing Ammannia baccifera leaf extract as a provider of reducing agents. A surface plasmon resonance (SPR) peak was observed at 413 nm in the UV–Vis absorption spectrum of AB-AgNPs, and it ensured the formation of nanoparticles. The unique bands in FTIR revealed the participation of phytochemicals with effective functional groups in the reduction and stabilization of AB-AgNPs. SEM revealed almost spherical-shaped AB-AgNPs, while EDX confirmed the presence of metallic silver with a strong signal at 3 eV. TEM further verified the formation of spherically-shaped AB-AgNPs, which ranged in size from 13 to 60 nm. The face-centered cubic (FCC) crystal structure of AB-AgNPs was confirmed by an XRD study. TGA, DLS, and Zeta potential studies also assured the stability and particle size distribution of AB-AgNPs. The DPPH and ABTS radicals were used to investigate the antioxidant activity of plant extract and AB-AgNPs, where the best performance of AB-AgNPs was observed in scavenging the ABTS radical with an EC50 value of 27.52 μg/mL. The green-produced AB-AgNPs showed strong catalytic activity for the breakdown of organic dyes (methylene blue, rhodamine B, and para-nitrophenol), and complete dye degradation was attained for each dye within 20 min. AB-AgNPs also showed efficient activity against Escherichia coli in antibacterial tests. These findings suggest that silver nanoparticles (AB-AgNPs) produced from the extract of Ammannia baccifera leaves, may find use in medicinal and environmental contexts. © 2024 Elsevier B.V.