Synthesis of Silver Nanoparticles with the use of Herbaceous Plant Extracts and Effect of Nanoparticles on Bacteria

The screening of aqueous extracts of herbaceous plants that grow on the territory of the Russian Federation with their subsequent use for the biosynthesis of silver nanoparticles (SNPs) in accordance with the principles of green chemistry has been performed. Extracts from the leaves of three plants (Mentha piperita L., Melilotus officinalis, and Archangelica officinalis) promoted efficient synthesis of SNPs, reducing the silver cation from AgNO3. SNP formation was tested on a spectrophotometer. Atomic force microscopy showed that plant extracts cause the formation of SNPs of different sizes—from 10 to 80 nm. Scanning electron microscopy revealed SNPs with various shapes and sizes; they were most commonly spherical. The obtained nanoparticles had a bactericidal effect on Escherichia coli K-12 and Pseudomonas aeruginosa PA01 (the latter being more resistant), and they suppressed the formation of E. coli biofilms. The obtained data show that the use of extracts from three herbaceous plants provides a readily available and ecologically safe method for the production of SNPs with antimicrobial activity.