Green synthesized silver and zinc oxide nanoparticles with antifungal, DNA protection, DNA cleavage, and cytotoxic activities

Abstract

The present study investigated the biological properties of silver (AgNPs) and zinc oxide (ZnONPs) nanoparticles synthesized through a green route using high molar precursor synthesis yielding stable powdered nanoparticles with dual bioactivity. Unlike conventional low-molar, colloidal green syntheses, this method yielded stable powdered nanoparticles with enhanced stability and biofunctional activity. AgNPs and ZnONPs were characterized using gravimetric analysis (GA), ultraviolet-visible spectroscopy (UV-Vis), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The synthesized AgNPs were rod to spherical, whereas ZnONPs displayed predominantly spherical to hexagonal morphology. Both nanoparticles showed antifungal activity against four agriculturally important fungi, viz., Colletotrichum gloeosporioides, Colletotrichum falcatum, Rhizoctonia solani, and Sclerotinia sclerotiorum, showed strong concentration-dependent inhibition under in vitro conditions. In detached fruit assays with Mangifera indica, both AgNPs and ZnONPs demonstrated significant dose-dependent inhibition of C. gloeosporioides. Detached leaf assays in Zea mays and Oryza sativa demonstrated substantial suppression of R. solani, with complete prevention of lesion development. Besides antifungal activity, both nanoparticles exhibited distinct biomolecular activities. ZnONPs demonstrated protective effects on DNA, whereas AgNPs induced DNA cleavage under oxidative and enzymatic stress conditions. The cytotoxic studies revealed significant inhibition of U87MG glioblastoma cells, reducing their viability in a dose dependent manner. Based on these findings, the study demonstrates that green synthesized nanoparticles possess strong potential for applications in agricultural and biological fields.