Green biosynthesis of selenium and zinc oxide nanoparticles using whole plant extract of Rheum ribes: Characterization, anticancer, and antimicrobial activity

Scientists are becoming interested in nanomedicine as a potential new approach to cancer detection and therapy in the twenty-first century. This paper presents the first investigation of the anticancer and antibacterial properties of selenium (Se) and zinc oxide (ZnO) nanoparticles obtained from Rheum ribes plant extract by a green synthesis method. Morphological and spectroscopic characterization of the synthesized nanoparticles was performed using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–Vis), which is a useful and straightforward technique for the preliminary characterisation of nanoparticles, dynamic light scattering (DLS) and X-ray diffraction (XRD) analysis. The size of the nanoparticles was determined to be 33 nm for Se-Nps and 32.8 nm for ZnO-Nps. The anticancer activity was assessed by the use of MTT, annexin V, caspase 3/7, and confocal microscopy imaging techniques. ZnO-Nps and Se-Nps were found to have significant antibacterial activity with MIC values for Escherichia coli (0.7 μg/mL, 0.63 μg/mL), and Staphylococcus aureus (1.56 μg/mL and 1.1 μg/mL). Furthermore, the antibacterial activity and the mechanism of action of the nanoparticles on E. coli and S. aureus bacteria were evaluated using microdilution and disc diffusion methods. In addition, the antiproliferative properties of ZnO-Np and Se-Np significantly suppressed the growth of A549 cells during a 24-hour incubation period (IC₅₀ 18.89 μg/mL ve 23.88 μg/mL). The results of the anti-cancer and anti-bacterial activity of the present study suggest that certain concentrations of Se-Np and ZnO-Np could be useful for pharmacological applications in cancer treatment and for coating surfaces for sterilization of medical equipment in healthcare settings, particularly in intensive care units.