Evaluation of Antifungal Activity of Ag Nanoparticles Synthetized by Green Chemistry against <i>Fusarium solani</i> and <i>Rhizopus stolonifera</i>

Abstract

Silver nanoparticles (AgNPs) have aroused great interest for applications as fungicides in agriculture. This study reports the synthesis of AgNPs by green chemistry using silver nitrate (AgNO3) as the precursor agent and a coriander leaf extract as the reducing agent and surfactant. The evaluation of their antifungal properties was carried out when placed in contact with Fusarium solani and Rhizopus stolonifer phytopathogens. The extract and AgNP characterizations were performed using UV–Vis spectroscopy, X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), dynamic light scattering (DLS) and scanning electron microscopy (SEM). The evaluation of antifungal properties was carried out by exposing the phytopathogens to different concentrations of AgNPs in PDA (Potato Dextrose Agar). It was found that it was possible to identify the presence of flavones and flavonoids in the extract, compounds that were also involved in the synthesis process of AgNPs. In addition, the UV–Vis analysis of the obtained AgNPs by green chemistry showed resonance peaks at around 428 nm. Furthermore, a high distribution of AgNP sizes, with high concentrations of below 100 nm, was identified, according to DLS measurements. Using SEM images, the information provided by DLS was confirmed, and a crystallite size of 29.24 nm was determined with the help of XRD measurements. Finally, when exposing the phytopathogens to the action of AgNPs, it was concluded that, at a concentration of 1 mg/mL AgNPs, their growth was totally inhibited.

Keywords

• Ag nanoparticles
• green chemistry
• antifungal
• phytopathogens
• avocado