Caracterização de extratos de Connarus perrottetii var. angustifolius Radlk e avaliação do comportamento antioxidante frente a espécies radicalares

Abstract

This paper describes the development of methodology for capillary electrophoresis with UV detection for the determination of 14 polyphenolic antioxidants in extracts of Connarus perrottetii var. angustifolius Radlk, a native plant of the Amazon forest. The method using capillary zone electrophoresis (CZE) allows simultaneous determination of 3-acetyilcoumarine, resveratrol, 6-hydroxycoumarin, catechin, rutin, ferulic acid, quercitrin, kaempferol, fisetin, myricetin, quercetin, caffeic acid, gallic acid and 4 hydroxicinnamic acid in the optimized conditions: borate buffer 20 mmol L-1 (pH 9.2) as work electrolyte containing 15% methanol (v /v), -20 kV potential separation, temperature 25 °C; hydrodynamic injection gravity 20 cm for 60 s. The method was validated on parameters of linearity, limit of detection, quantification limit, precision and accuracy, and was used in the analysis of aqueous infusion and ethanol, butanol and ethyl acetate plant fractions. The method was capable of identifying the antioxidants present in samples with high selectivity and sensitivity. In infusion and in ethanol and butanol fractions was found the presence of catechin and rutin as major compounds, which makes up about 0.5% of the total mass of medicinal plant. The obtained dry extracts (ethanol and butanol) allowed the concentration of rutin and catechin around 20 times compared to the dry plant. In addition, tests were performed to measure the antioxidant activity of the extracts against DPPH radical, superoxide anion radical, hydroxyl and peroxyl. A sample of aqueous infusion of 10% showed the highest activity against most free radicals. It corroborates the results of characterization by capillary electrophoresis, where catechin and rutin were determined in relatively high concentrations in the aqueous infusion. But all treatments of the samples showed good antiradicalar behavior with the methodologies applied. Against DPPH, for example, the ethyl acetate fraction showed a potential of 94,43%. Against superoxide and hydroxyl radicals, the butanol fraction showed the best performance: 64,23% and 74,97%, respectively.