Green synthesis of silver nanoparticles using Illicium verum extract: Optimization and characterization for biomedical applications

Abstract

Abstract The synthesis of noble metal nanoparticles is currently experiencing substantial development and considerable attention. Plant extracts are commonly used for the biological synthesis of nanoparticles because they contain biologically active constituents. In our present study, silver nanoparticles (AgNPs) were synthesized using an aqueous Illicium verum (Star anise) extract to evaluate their antimicrobial, antioxidant, and cytotoxicity activities. For maximum yields of AgNPs, the extract (2.5 ml), silver ions (500 µM), and pH (8) were shown to be the ideal nanoparticle production parameters. The visual colour shifted from pale brown to dark brown when the ultraviolet-visible spectrophotometer was used to validate the synthesis of AgNPs. A transmission electron microscope was utilized to evaluate nanoparticles’ physical nature. The presence of silver metal with face-centred cubic symmetry was confirmed by X-ray diffraction analysis. Fourier-transform infrared spectroscopy was used to identify the functional groups in charge of reducing silver ions (Ag+) and the stability of AgNPs produced using the I. verum aqueous extract. The agar well diffusion method investigated the antibacterial activity of I. verum silver nanoparticles (Iv-AgNPs) against pathogenic bacteria and fungi. At higher doses (100 µg·mL−1), the highest zone of inhibition was observed, and spherical AgNPs demonstrated the antibacterial activity. The I. verum extract and Iv-AgNPs enhanced (70%) their free radical scavenging activity at 500 µg·mL−1 according to the 2,2-diphenyl-1-picrylhydrazyl assay. Moreover, the cytotoxicity of Iv-AgNPs against the HCT-116 human colon cancer cell line indicated cell inhibition in a dose-dependent manner. Ultimately, the findings of this study indicate that techniques used to produce AgNPs are environmental friendly, cost-effective, harmless, uncomplicated, and can effectively tackle a broad spectrum of medical and nutritional concerns.