Antimicrobial activity of a new formulation based on silver nanoparticles synthesized in situ with a plant extract from Córdoba (Argentina)

Abstract

The disinfectants used in the hospital environment do not ensure the complete removal/elimination of bacteria and/or biofilms in the different products for medical use. This contributes to the rise of resistant microorganisms and the urgent need to develop new antimicrobial agents. For this reason, work is being done to obtain new formulations based on nanoparticles, such as AgNPs, which have properties of great interest due to their ability to inhibit microorganisms. Traditionally, the synthesis process involves substances that are harmful to the environment. This proposal uses green chemistry to reduce the energy consumption and toxical waste. Moreover, it would also have the advantage of shorter action times, helping with the infectious disease transmitted by fomites. Ten vegetable species from the province of Córdoba were collected during the flowering and/or fruiting season, and were dried in the shade at room temperature. Subsequently, extracts were made from the crushed leaves to a fine powder and macerated at room temperature in distilled water for 7 days. Next, the reducing capacity of the plant extracts was evaluated using the Folin-Ciocalteu reagent and using tannic acid as a standard.The species that presented the greatest reducing capacity were selected to conduct the synthesis. In this case, studies of the aqueous extract of Erythrina crista-galli L. “Ceibo” (Fabaceae) are shown. The solvo thermal reaction was carried out in different conditions. The optimal one was using 50 uL of aqueous plant extract (100%) and 150 uL of AgNO3 solution (0.01 M). AgNP formation was determined by spectrophotometric detection of the plasmon, with absorption maxima at 400 nm.The antimicrobial capacity of the nanoparticles synthesized with the plant extract was evaluated in Escherichia coli ATCC 25922 (104 CFU/mL), a Gram-negative bacterium. Colonies were counted on tryptein soy agar plate after 24 hours of incubation of the bacterial inoculum with the AgNPs at 37°C, total growth inhibition was evidentThe study of antimicrobial activity is being continued, including clinical strains, biofilm-forming strains and the characterization of the AgNPs.