Silver nanoparticles (AgNPs) were fabricated using Trigonella foenum-graceum L. leaf extract, belonging to the variety HM 425, as leaf extracts are a rich source of phytochemicals such as polyphenols, flavonoids, and sugars, which function as reducing, stabilizing, and capping agents in the reduction of silver ions to AgNPs. These phytochemicals were quantitatively determined in leaf extracts, and then, their ability to mediate AgNP biosynthesis was assessed. The optical, structural, and morphological properties of as-synthesized AgNPs were characterized using UV-visible spectroscopy, a particle size analyzer (PSA), FESEM (field emission scanning electron microscopy), HRTEM (high-resolution transmission electron microscopy), and FTIR (Fourier transform infrared spectroscopy). HRTEM analysis demonstrated the formation of spherically shaped AgNPs with a diameter of 4-22 nm. By using the well diffusion method, the antimicrobial potency of AgNPs and leaf extract was evaluated against microbial strains of Staphylococcus aureus, Xanthomonas spp., Macrophomina phaseolina, and Fusarium oxysporum. AgNPs showed significant antioxidant efficacy with IC50 = 426.25 µg/mL in comparison to leaf extract with IC50 = 432.50 µg/mL against 2,2-diphenyl-1-picrylhydrazyl (DPPH). The AgNPs (64.36 mg AAE/g) demonstrated greater total antioxidant capacity using the phosphomolybdneum assay compared to the aqueous leaf extract (55.61 mg AAE/g) at a concentration of 1100 μg/mL. Based on these findings, AgNPs may indeed be useful for biomedical applications and drug delivery systems in the future.
Keywords: antimicrobial; antioxidant; phytochemicals; silver nanoparticles.