Synthesis of NiO Nanoparticles Prepared via a Green Process Using Azadirachta indica, Morinda citrifolia, and Terminalia elliptica for Biological Applications

Developing a low-cost, high-efficiency, and environmentally friendly approach to synthesize nickel oxide (NiO) nanoparticles (NPs) for biomedical applications has become a research focus in the current scenario. In the present investigation, the NiO NPs were synthesized via a green process using different plant extracts, such as Azadirachta indica (N1), Morinda citrifolia (N2), and Terminalia elliptica (N3). X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), and photoluminescence excitation spectroscopy were used to investigate the evolution of the size, morphology, chemical composition, and surface defect of NiO NPs. The synthesized NiO NPs were exhibited as cubic structures. As compared to conventional antibiotics amoxicillin, Morinda citrifolia (N2) and Terminalia elliptica (N3) medicated NiO nanoparticles, Azadirachta indica mediated NiO (N1) exhibits more antibacterial activity. From the antioxidant activity, the DPPH assay of N1, N2, N3, and vitamin C samples exhibited free radical scavenging potential. There are increases in the inhibition percentage with increases in the concentrations of these NiO NPs. In addition, the N1 sample demonstrates higher radical scavenging activity than N2 and N3. From the observed results, we believe that Azadirachta indica mediated N1 condition synthesized NiO NPs are very promising biocidal nanomaterials against human pathogens, which will be medically crucial for clinical applications.