Biogenic Gold Nanoparticles Fabricated from Withania coagulans Leaf Extract: Synthesis, Characterization, and Broad-Spectrum Antimicrobial Assessment

Abstract

Aqueous extracts of Withania coagulans leaves were used to phytosynthesize green AuNPs.  The AuNPs synthesized were found to be stable nano-crystalline sphericals with a size range of 20 to 100 nm. The AuNPs λmax peak was found at 550 nm, demonstrating the accurate production of AuNPs. The sharp Au^o peak in EDX analysis, together with other organic peaks, demonstrate that phytochemicals in plant extracts efficiently lowered the ionic Au⁺³ by serving as an efficient biocapping and bioreducing agent. In comparison to aqueous leaves extract, the in-vitro activities of these AuNPs show that they have excellent antifungal activity against F. solani (92%), F. oxysporum (91%), M. furfur (90%), Penecillium and C. albicans (89%). Antibacterial activity was shown to be moderate to good against S. aureus (63%), and K. pnuemoniae (54%).