One-Step Functionalization of Silver Nanoparticles Using the Orsellinic Acid Compound Isolated From the Endophytic Fungus Epicoccum Nigrum: Characterization and Antifungal Activity

A simple green method for the synthesis of silver nanoparticles (AgNPs) using the natural isolated orsellinic acid compound has been investigated for the first time. The present work describes a one-step functionalization of AgNPs using orsellinic acid as a reducing agent to convert Ag+ cations to AgNPs. This process eliminates the use of external toxic chemical reducing agents to provide a completely green synthetic route. The biosynthesized AgNPs were characterized by means of high spectroscopic and microscopic techniques. The results showed the formation of high crystalline spherical AgNPs with an average diameter of 22.5 ±1.8 nm. Moreover, the Fourier transform infrared (FT-IR) analysis indicated that AgNPs are covered with a thin layer of biomoieties on their surface and suggested that the hydroxyl groups of orsellinic acid compound are involved in the reduction of the Ag+ ions, capping and stabilizing the formed nanoparticles. Remarkably, the formed AgNPs showed potent antifungal activity against the phytopathogenic fungus Alternaria solani causing early blight disease of tomato plants. Those findings emphasize that such biocompatible green silver nanoparticles with their excellent antifungal activities may find their applications as new bio-fungicides against various plant pathogenic fungi in the field of crop improvement and plant disease management.