Harnessing antioxidant and antifungal potential of carbohydrate-based solanum nigrum silver nanoparticles

Abstract This study aims to evaluate the antifungal action of green-synthesized silver nanoparticles derived from the aqueous leaf extract of Solanum nigrum and biocapped with glucose (G-AgNPs). G-AgNPs revealed a maximum absorption peak at 440 nm and demonstrated mixed morphology, comprising both spherical and rod-shaped nanoparticles, as confirmed by FE-SEM. However, transmission electron microscopy shows that G-AgNPs were predominantly spherical, with an average size of 23 nm. The antioxidant potential of these nanoparticles was confirmed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and phosphomolybdate assays. DPPH assay reported that G-AgNPs exhibited 69% inhibition at 250 μg ml −1 (IC 50 = 74.9 ± 0.6), while leaf extract showed 65% inhibition (IC 50 = 85 ± 0.01) at the same concentration. The results of the phosphomolybdate assay depicted that leaf extract exhibited a total antioxidant capacity (TAC) of 341.94 ± 1.24 mg ascorbic acid equivalents per gram (AAE/g), whereas G-AgNPs demonstrated a TAC of 75.34 ± 2.81 mg AAE/g. G-AgNPs were analyzed against pathogenic ( Aspergillus niger ) and non-pathogenic ( Trichoderma asperellum ) fungi by the disc diffusion method, and the results were expressed as a zone of inhibition. G-AgNPs exhibited antifungal action against A. niger with a maximum 10 ± 0.0 mm zone of inhibition at a concentration of 5 μg disc −1 , whereas G-AgNPs were ineffective against T. asperellum .