Characterization of green route synthesized zinc oxide nanoparticles using Cyperus rotundus rhizome extract: Antioxidant, antibacterial, anticancer and photocatalytic potential

Cyperus rotundus rhizome has been employed in traditional Chinese and Indian Ayurvedic herbal formulations. Green synthesis of metal oxide nanoparticles has gained significant attention due to its economic, biocompatibility, non-toxicity and eco-friendliness. The current study confirmed the biosynthesized zinc oxide nanoparticles (ZnONPs) by an ultraviolet–visible absorption spectrum of 353 nm. Fourier transform infrared spectroscopy analysis demonstrated that bioactive functional groups served as reducing and stabilizing agents for ZnONPs. Further, X-ray powder diffraction (XRD) patterns showed crystalline nature with a hexagonal phase and strongly correlated with JCPDS file number 36-1451. The electron microscopic studies revealed irregular spherical particles with a size range of 17–100 nm and EDAX analysis validated the crystalline purity of ZnONPs. The average size of the ZnONPs determined by dynamic light scattering was 95.89 nm and the zeta potential was −12.1 mV, indicating stability of the particles. Moreover, the ZnONPs exhibited noticeable antioxidant potential by scavenging free radicals on DPPH (59.74%), ABTs (66.35%), nitric oxide (65.75%) and reducing power (63.94%) in a dose-dependent manner. The bacterial cell damages were observed through FESEM, confirming the antibacterial efficacy of ZnONPs. Further, the ZnONPs exhibited remarkable cytotoxic effect (62.34 μg/mL) against breast cancer cells and subsequent fluorescence staining demonstrated apoptotic and necrotic features in damaged cells. The photocatalytic effectiveness of ZnONPs demonstrated increased eco-bioremediation capabilities by degrading crystal violet (80.69%) and methylene blue (88.93%) dyes. Thus, this is the first report on ZnONPs synthesized using C. rotundus could be explored as a promising material for biological and photocatalytic applications.