Green Synthesis and Antifungal Activity of <i>Sophora flavescens</i> ‐Mediated Silver Nanoparticles

This study describes a green, simple, and low‐cost biological way tosynthesize silvernanoparticles (AgNPs)using the ethanolic root extract of Sophora flavescens . It investigates its antifungal activity against four strains of Candida albicans , Candida tropicalis , Candida utilis , and Aspergillus flavus . Atomic force microscopy, ultraviolet–visible, Fourier transform infrared (FTIR), zeta potential, and atomic absorption spectroscopy were used to explore the particles' optical, structural, and morphological properties. The results of these tests showed that after green synthesis of nanoparticles, their size ranged between 4 and 13 nm without aggregates or precipitation. Particles were also found to have colloidal stability with a negative surface charge of −27 mV and were uniformly distributed. FTIR spectroscopy analysis further confirmed that bioactive compounds within the plant aided the reduction of silver nitrate to silver cation, thus increasing the stability of nanoparticles. The presence of an absorption peak associated with the surface plasmon resonance of the AgNPs was observed by spectroscopic analysis. In addition, the AgNPs showed the highest antifungal activity at the 9% green AgNPs, with activity against C. albicans and C. utilis at 13.00 mm and 15.67 mm, respectively. Whereas C. tropicalis and A. flavus, were most inhibited by the 9% plant extract, with inhibition zones of 11.00 mm and 13.67 mm, respectively. These experiments suggest that the effectiveness of green synthesis of AgNPs toward human pathogenic fungi may provide additional tools to help treat fungal infections, although more research needs to be done.