Utilization of aqueous broccoli florets extract for green synthesis and characterization of silver nanoparticles, with potential biological applications

Abstract

The process of creating nanoparticles using chemicals is not eco-friendly. However, a more environmentally conscious approach known as green chemistry, which involves using vegetable-mediated nanoparticle production, combines nanotechnology with biotechnology. In this study, the researchers aimed to assess the effectiveness of the green chemistry technique in producing silver nanoparticles using an liquid extract from broccoli florets (Brassica oleracea) under ideal environment. The successful production of silver nanoparticles was achieved through silver nitrate (AgNO₃) biological reduction with the help of an aqueous broccoli florets extract at a slightly acidic pH of 6–7. The silver nanoparticles occurrence was shown by a change of color that moved from colorless to reddish-brown. To characterize the green-produced nanoparticles, various analytical techniques such as Ultraviolet–Visible Spectroscopy (UV-VIS), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-ray Spectroscopy (EDAX) were employed. The antioxidant properties of the formed silver nanoparticles (AgNPs) were examined in vitro using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric Reducing Antioxidant Power (FRAP) tests. Additionally, the antibacterial properties of AgNPs against various pathogenic bacteria was evaluated. The reduction procedure was easy and simple manageable, with UV–Vis spectroscopy indicating the surface plasmon resonance (SPR) presence at 425 nm. FTIR was utilized to identify active chemical groups in the biomass before and after reduction. SEM and X-ray diffraction analyses indicated that the silver nanoparticles had an average the size of individual particles of 33 nm and exhibited a face-centered cubic (FCC) structure. EDAX analysis confirmed the occurrence of elemental silver in the nanoparticles. The study demonstrated that the biosynthesis of AgNPs led to significant variations in antioxidant activity, which was dose-dependent and showed a similar pattern to the testing of the scarfing action of the ascorbic acid against free radicals using DPPH and FRAP. The AgNPs also dispalyed firm deep-spectrum antibacterial action observed against the tested pathogenic bacteria, outperforming certain medications. Interestingly, the silver nanoparticles remained stable at ambient temperature for 25 days without precipitation, retaining their antioxidant and antibacterial properties. In conclusion, the research findings suggest that an aqueous extract of fresh broccoli florets can serve as a viable and environmentally friendly method for producing stable silver nanoparticles with beneficial antioxidant and antibacterial characteristics.