Síntese verde e caracterização de nanopartículas de prata usando extrato aquoso de erva mate (Ilex paraguariensis)

Abstract

The use of green synthesis to obtain silver nanoparticles is an efficient method that has the advantage of not using reagents and solvents that can cause toxicity in both synthesis and waste. In this work was first reported as silver ion reducing silver ion, aqueous extract of yerba mate (Ilex paraguariensis), a plant typical of the south of South America used in the making of hot (chimarrão) or cold (tereré) beverage in the region. It was carried out experimental design of complete factorial 2² with triplicate at the midpoint, and the extract concentration of 5 ± 2, and pH 5; 6.8 and 8.5. The size measurament of the obtained silver particles was performed by UV-visible and dynamic light scattering (DLS); functional compounds were analyzed by Infrared Spectroscopy Fourier Transform (FTIR) were also carried out analysis to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the nanoparticles obtained for Promoting Foodborne Diseases (DTAs ) bacteria, P. aeruginosa, S. aureus and B. cereus. After analyzing the results, the UVVis presented absorbance peaks between 423-449nm, and the half-width (FWHM) ranging from 112 to 280nm. For DLS, dimensions ranged from 34nm (E7 experiment, 2.5% extract concentration and pH 8.5) at 154nm (E8 experiment, 7.5% extract concentration and pH 5), while for PDI ranging from 0.29 (E9, 7.5% extract concentration and pH 8.5) to 0.51 (E7). For FTIR, it is suggested that aromatic chain compounds, polyphenols and/or carbohydrates may have been responsible for the bioreduction of Ag+ to Ag0. In general the synthesized AgNPs showed bacteriostatic and bactericidal activity to P. aeruginosa, B. cereus and S. aureus, however, for the Gram-negative P. aeruginosa higher concentration of AgNPs were required for bacterial inhibition, while B. cereus required lowest concentration AgNPs.