Characterization of NiONPs synthesized by aqueous extract of orange fruit waste and assessed their antimicrobial and antioxidant potential.

This research was performed to evaluate the nickel oxide nanoparticles (NiONPs) fabricating potential of orange fruit waste (OFW) aqueous extract. Moreover characterize the synthesized OFW-NiONPs through standard techniques such as UV-vis. spectrophotometer, Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) and Scanning Electron Microscope (SEM) analyses. Furthermore, the antimicrobial and antioxidant potential of OFW-NiONPs were studied against most common microbial pathogens (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, and Aspergillus niger) and free radicals (2,2-diphenyl-1-picrylhydrazyl (DPPH), H2O2, OH, and FRAP). A sharp absorbance peak was obtained at 324 nm under UV-vis spectrum analysis that confirmed that the synthesis of OFW-NiONPs and it has been capped and stabilized by numbers of active functional groups studied through FTIR analysis. SEM and DLS analyses revealed that the cubic and triangle shaped OFW-NiONPs with the size intensity distribution was ranging from 21 nm to 130 nm. Interestingly, the OFW-NiONPs showed remarkable antimicrobial activity against the common microbial pathogens in the order of E. coli > A. niger > K. pneumoniae > B. subtilis > S. aureus at increased concentration of 200 µg mL-1. Similarly, the synthesized OFW-NiONPs also possess significant free radicals scavenging activity against DPPH, OH, and FRAP. These results conclude that this OFW-NiONPs can be considered for some biomedical applications after the investigations of some in-vivo research.