The preparation of nickel oxide nanoparticles (NiO NPs) was carried out using an environmentally friendly and novel green synthetic strategy that included the use of Buxus wallichiana leaf extract as a reducing agent. Energy-dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), scanning electron microscope (SEM), and thermogravimetric analysis (TGA) techniques were used to characterize the resulting NiO NPs. At various concentrations, NiO NPs were tested for their percentage scavenging activity against the ABTS (2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) free radical, with an IC50 value of 234.84 g/L. Furthermore, the bactericidal activity of NiO NPs was studied by the agar well diffusion method against two Gram-positive bacterial strains (B. licheniformis and B. subtilis) and two Gram-negative bacterial strains (E. coli and K. pneumoniae).

This research was planned to synthesize a biological potent nanomaterials via an eco-friendly process to combat the diseases causing bacteria and the free radicals generated inside the body. For this purpose, a green synthesis process was employed to prepare SnO₂ nanoparticles by utilizing leaf extract of Populus ciliate, and they were characterized via different physico-chemical techniques. The crystallite size of SnO₂ nanoparticles was found to be 58.5 nm. The calculated band gap energy of SnO₂ nanoparticles was 3.36 eV. The SnO₂ nanoparticles showed 38, 49, 57, and 72% antioxidant activity at concentrations of 100, 200, 300, and 400 L with 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonicacid) (ABTS) assays. The antibacterial effects of prepared SnO₂ nanoparticles were studied using the agar well diffusion method against Gram-positive bacteria (S. pyogene and S. aureus) and Gram-negative bacteria (K. pneumoniae and E. coli). Both the antioxidant activity and antibacterial activity were seen to increase with increasing the concentration of the nanoparticles.

This study was planned to synthesize a multifunctional nanomaterial that can effectively encounter the organic pollutants, multidrug-resistant bacteria and reactive free radicals. The Bergenia ciliate (B. ciliate) leaves extract was used as a reducing and capping agent for the synthesis of nickel oxide nanoparticles (NiO NP). The physicochemical properties were studied through X-ray diffractometre (XRD), energy dispersive X-ray (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible and Fourier transform infrared (FTIR) spectroscopies. The highly crystalline monoclinic NiO NPs were synthesized with crystallite size of 27.45 nm. The average particle size derived from TEM micrograph was 49.35 nm whereas the calculated band gap for NiO NPs was 3.78 eV. The photocatalytic study shows that 92.17% of the rhodamine 6G (Rh-6G) was efficiently degraded in the presence of NiO NPs. The agar well diffusion method was applied to examine the antibacterial activity of NiO NPs and the activity was found higher against Gram-negative bacteria (GNB) as compared to Gram-positive bacteria (GPB). The ABTS free radical scavenging activity was also performed, however, the activity was found less than the standard.