The application of silver nanoparticles (AgNPs)-based antibacterial therapeutics has emerged as a feasible alternative to traditional antibiotic therapy due to cost-effectiveness and lower possibility of non-evolution of resistant strains. In the present paper, the aqueous extract of wheat (Triticum aestivum) and rice (Oryza sativa) leaflets were used for the fabrication of well-dispersed AgNPs of average size 19.11 and 33.85 nm, respectively, under the controlled condition of pH 10.0 + 0.1 and temperature 80°C + 1°C. This bottom-up approach of AgNPs production was simple, eco-friendly, inexpensive, and highly reproducible. The synthesized AgNPs were characterized by UV-Visible spectroscopy, dynamic light scattering, fourier transform infrared spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray. Agarwell diffusion and (2, 3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide) (XTT) colorimetric methods revealed the bactericidal potential of synthesized AgNPs against Gram-positive and Gram-negative pathogenic bacteria with minimum inhibitory concentration (MIC) values ranges from 125 to 500 µg/ml. AgNPs presented better potency against Gram-negative bacteria compared to Gram-positive bacteria. Interestingly, Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli demonstrated a hormetic response (positive stimulated growth) at a sub-lethal concentration (
Key words: AgNPs, Antibacterial effect, Crop plants; Hormetic response; XTT-colorimetric assay
|
