In vitro antibacterial effect of silver nanoparticles synthetized using Agastache foeniculum plant and callus extracts

Abstract

Green synthesis is an environmentally friendly, safe, affordable and low-cost method for various morphologies nanoparticles producing using bacterial, fungi or plant aqueous extracts. Antimicrobial activity of silver nanoparticles obtained from Agastache foeniculum plants and callus aqueous extracts has been demonstrated against hospital infections—Staphylococcus aureus, Staphylococcus haemolyticus, Klebsiella pneumonia and Streptococcus pneumonia. The synthesized nanoparticles were characterized by UV-spectroscopy and transmission electron microscopy. The nanoparticles had a spherical shape with an average size diameter of 19.81 ± 5.32 nm and 9.51 ± 1.55 nm for synthesis based on plant and callus extracts respectively. The minimum inhibitory concentration for the nanoparticles was 6.25 to 25.00 mg/L for all tested strains, except for Acinetobacter baumannii, which experimental cultivation conditions were inappropriate. Antioxidant capacity of the extracts expressed in total phenolic and flavonoid contents also has been shown. Total phenolic content of callus extract was 1.97 ± 0.06 mg/g in hydroquinone equivalents, which is higher than plant's extract. Supposedly biogenic nanoparticles morphology depends on the concentration of compounds with antioxidant activity in extracts. Initial extracts have proved low-cytotoxicity, indicating synthesis safety. The nanoparticles can be used as a basis for products development to prevent hospital infections spreading, including those with antibiotic resistance.

Keywords

• green synthesis
• silver nanoparticles
• antibacterial activities
• agastache
• hospital infections