Estudo da atividade antibacteriana do picolinato de sacarose em Escherichia coli

Abstract

Sucrose esters are generally used as surfactants, fat substitutes and antibiotics. The aim of the present study was to synthesize new sucrose esters derived from picolinic acid (2-pyridine carboxylic acid) and study in vitro antimicrobial activity on the Gram-negative pathogenic bacterium Escherichia coli. The synthesis of sucrose picolinate was performed through the transesterification of sucrose with methyl picolinate under anhydrous conditions at 80°C using dimethyl sulfoxide (DMSO) as the solvent and K2CO3 as the catalyst. The separation of the formed isomers was performed by HPLC in a semi-preparative chromatograph system. Five fractions were collected and applied to a disc-diffusion antibiogram in solid-medium tests at concentrations of 150, 300, 450, 600, 750 and 900 μg/mL. Fractions 2, 4 and 6 were active against E. coli. Fraction 4 (900 μg/mL) was the most efficient and was selected for the determination of antimicrobial activity in synergistic tests with EDTA at concentrations of 250, 500 and 750 μg/mL. The best result was obtained with 750 μg/mL of EDTA. Fraction 4 was characterized as a monosubstituted sucrose ester by FTIR and mass spectrometry (ESI-MS).