Nanoworld is an attractive sphere with the potential to explore novel nanomaterials with valuable applications in medicinal science. Herein, we report an efficient and ecofriendly approach for the synthesis of Nickel oxide nanoparticles (NiO NPs) via a solution combustion method using Areca catechu leaf extract. As-prepared NiO NPs were characterized using various analytical tools such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-Visible spectroscopy (UV-Vis). XRD analysis illustrates that synthesized NiO NPs are hexagonal structured crystallites with an average size of 5.46 nm and a hexagonal-shaped morphology with slight agglomeration. The morphology, size, and shape of the obtained material was further confirmed using SEM and TEM analysis. In addition, as-prepared NiO NPs have shown potential antidiabetic and anticancer properties. Our results suggest that the inhibition of α-amylase enzyme with IC 50 value 268.13 µg/mL may be one of the feasible ways through which the NiO NPs exert their hypoglycemic effect. Furthermore, cytotoxic activity performed using NiO NPs exhibited against human lung cancer cell line (A549) proved that the prepared NiO NPs have significant anticancer activity with 93.349 μg/mL at 50% inhibition concentration. The biological assay results revealed that NiO NPs exhibited significant cytotoxicity against human lung cancer cell line (A549) in a dose-dependent manner from 0–100 μg/mL, showing considerable cell viability. Further, the systematic approach deliberates the NiO NPs as a function of phenolic extracts of A. catechu with vast potential for many biological and biomedical applications.

This work focused on employing Calotropis gigantea leaf extract as reducing agent/fuel and (Zn(NO ₃ ) ₂ .6H ₂ O), (Cu(NO ₃ ) ₂ .3H ₂ O) as precursors to synthesise ZnO–CuO nanocomposite by solution combustion method. Prepared nanocomposites were characterised using x-ray powder diffraction (XRD), scanning electron microscope (SEM) with energy dispersive x-ray analysis (EDAX), high-resolution transmission electron microscopy (HR-TEM) and Fourier transform infrared spectroscopy (FT-IR). XRD result revealed crystalline nature with average crystallite size of 35 nm. SEM images indicate that particles are agglomerated and EDAX confirms the composition of elements with pure phase. HR-TEM images indicated that average sizes of the prepared ZnO–CuO nanocomposite were 10–40 nm with spherical and hexagonal shapes. The presence of functional groups such as Zn−O, Cu−O, −OH, −C–O, and C–H was confirmed by FT-IR spectrum. The optical energy bandgap was estimated using Kubelka-Munk equation by the aid of diffuse reflectance spectroscopy (DRS). The synthesised nanocomposite showed superior photocatalytic activity of degradation efficiency 97.93% against methylene blue dye. Further, anti - bacterial activity was investigated by agar well diffusion procedure against two bacterial strains ( Escherichia coli and Staphylococcus aureus) and significant zone of inhibition to the bacterial strains was observed.