Green synthesis of silver nanoparticles using aqueous leaf extract of ocimum basilicum and investigation of their potential antibacterial activity

Abstract

Bacterial resistance to antibiotics has emerged as a common medical problem that requires urgent attention. Thus, investigation on seeking for a better alternative is a paramount issue. Recently, silver nanoparticles (SNPs) have shown promising results as bactericidal agent against both gram positive and gram negative bacteria without cytotoxicity. The objectives of this study were to synthesize SNPs using Ocimum basilicum leaf extract, characterize the nanoparticles and investigate their antibacterial activity. SNPs were prepared by mixing AgNO3 precursor solution with the leaf extract of O. basilicum. The biologically synthesized SNPs were characterized using UV-Visible spectral, transmission electron microscopic and fourier-transform infrared spectroscopic analyses. Bactericidal efficiency of the biologically synthesized SNPs was examined against certain bacteria known for their resistance against conventional antibiotics. The results indicated that the synthesized SNPs were crystalline, spherical in nature and their size ranged between 18.7-26.2 nm. Also, the antibacterial sensitivity testing showed a great inhibitory effect of SNPs against the test bacterial pathogens which included Proteus vulgaris, Escherichia coli, Klebsiella pneumonia and Bacillus sp. Our finding suggest that biologically synthesized SNPs using aqueous leaf extract of O. bascilicum has a promising antimicrobial activity against some pathogenic bacteria with proven resistance to conventional antibiotics.