Efficacy of Calotropis gigantea L. flower extract and biosynthesized silver nanoparticles against fungal pathogens

Abstract

Following the emergence of resistant fungal pathogens, plants mediated biosynthesized silver nanoparticles (AgNPs) have been recognized as promising tools to combat fungal pathogens. This study evaluated the potency of Calotropis gigantea L. in producing AgNPs followed by testing their antifungal effects against fungal pathogens. AgNPs were successfully produced utilizing the aqueous extract of C. gigantea flower extract. The biosynthesized AgNPs were characterized by UV-Vis spectroscopy, SEM, EDX and XRD analyzes. The visible brown color validated the synthesis of AgNPs and the UV-Vis spectrum revealed a maximum absorption at 438 nm. The SEM and EDX analyzes revealed that the AgNPs were rod shaped ranging from 10 nm to 150 nm in size along with the presence of elemental Ag. The X-ray diffraction further indicated that the biosynthesized AgNPs were crystalline in nature. The C. gigantea flower extract and biosynthesized AgNPs effectively mitigate the fungal growth viz.: Aspergillus aculeatus, Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Cryptococcus neoformans, Phialophora verrucosa and Sporothrix schenckii. The maximum inhibition in growth by biosynthesized AgNPs was observed against P. verrucosa (13 mm) whereas the flower extract of C. gigantea was most effective against P. verrucosa (14.5 mm) and S. schenckii (13.5 mm). These findings may suggest C. gigantea flower extract as a green solution for biosynthesizing AgNPs with tremendous potentiality towards controlling human and plant pathogenic fungus.