Green Synthesis of Silver Nanoparticles Using Bellevalia Flexuosa Leaves Extract

Silver nanoparticles (AgNPs) have broad biocidal activities, and are widely employed as an active ingredient in antiseptic, anti-viral, and anti-inflammatory preparations. Green-synthesizing AgNPs would be a rapid, cheap, and environmentally friendly method of synthesis. The methanolic extract of the leaves of <i>Bellevalia flexuosa</i> Boiss. (Asparagaceae) was used for the green synthesis of the AgNPs. The effects of the pH and the concentration of silver nitrate (AgNO₃) on the synthesis of the AgNPs were investigated. The AgNPs produced above pH 10, and 1 mM of AgNO₃ resulted in lower hydrodynamic diameters. Ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction proved the formation of the AgNPs, with a face-centered, cubed geometry. Scanning electron microscopy images showed colloidal and well-dispersed nanoparticles. In addition, the antibacterial activities of the prepared AgNPs were assessed by optical densities (ODs) against Gram-positive bacteria (<i>Enterococcus faecalis</i> and <i>Staphylococcus epidermidis</i>) and Gram-negative bacteria (<i>Pseudomonas aeruginosa</i>, <i>Escherichia coli</i>, <i>Klebsiella pneumoniae</i>, and <i>Salmonella enterica</i>). The broths of Gram-negative and Gram-positive bacteria that contained AgNPs, showed lower OD values compared to the controls. In conclusion, AgNPs were prepared using <i>B. flexuosa</i> methanolic extract, and showed antibacterial activity against the tested bacterial strains.