Phytogenic Synthesis and Characterization of Silver Metallic/Bimetallic Nanoparticles Using Beta vulgaris L. Extract and Assessments of Their Potential Biological Activities

Abstract

The synthesis of novel nanomedicines through eco-friendly protocols has been applied on a large scale with the prediction of discovering alternate therapies. The current work attained phytogenic synthesis of Ag-mNPs, AgSeO2-bmNPs, and Ag-TiO2-bmNPs through bio-reduction using an aqueous extract of Beta vulgaris (red beetroot). The phytochemical profile of the eco-friendly synthesized metallic/bimetallic nanoparticles was studied. The optical properties of nano-solutions were studied via UV-visible spectroscopy. The Fourier-transform infrared spectroscopy (FT-IR) spectral analyses revealed that stretching vibrations at wavenumbers 3303.81–3327.81 cm−1 attributed to phenolic hydroxyl groups documented shifts in the values in this range owing to proton dissociation through the bio-reduction of the metal ions. The surface morphology and the charge of the nanoparticles were investigated using a Transmission Electron Microscope (TEM) and zeta potential analyses. The prepared nano-solutions showed lower antioxidant activity (1,1-Diphenyl-2-picrylhydrazyl (DPPH•) and phosphomolybdate assays) than the plant extract. These results together with phytochemical analyses support the participation of the reactive species (phenolic contents) in the bio-reduction of the metal ions in the solutions through the formation of metallic/bimetallic nanoparticles. Ag-mNPs, AgSeO2-bmNPs, and Ag-TiO2-bmNPs showed antibacterial potentiality. AgSeO2-bmNPs were superior with inhibitory zone diameters of 34.7, 37.7, 11.7, and 32.7 mm against Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, and Salmonella enterica, respectively. Applying the Methylthiazole Tetrazolium (MTT) assay, the Ag-TiO2 bmNPs revealed potent cytotoxicity against the HePG2 tumor cell line (IC50 = 18.18 ± 1.5 µg/mL), while Ag-SeO2 bmNPs revealed the most potent cytotoxicity against the MCF-7 cell line (IC50 = 17.92 ± 1.4 µg/mL).