Avaliação da estabilidade de compostos fenólicos e capacidade antioxidante de extrato aquoso de alcachofra

Abstract

Some beneficial properties of artichoke (Cynara scolymus L.) has been related to its phenolic compounds and antioxidant capacity that they can produce. Thus, the aim of this study was to identify the most suitable solvent for the extraction of Artichoke polyphenols, evaluate the stability of that in aqueous extracts stored under different conditions of luminosity and temperature, and determine the antioxidant capacity in vitro by different methods. For the extraction test, partially dried samples were used and tested two solvents (methanol and ethanol), both in 70% aqueous solution. The content of phenolic compounds was estimated by spectrophotometric methodology, using the Folin-Ciocalteau as a reagent. To assess the stability of phenolic compounds, the experiment was composed by three treatments consisted of different storage conditions (coolant temperature in the absence of light, room temperature in the absence of light and room temperature in the presence of light), and the extracts were evaluated for 35 days at intervals of 05 and 10 days. For the determination of antioxidant capacity in vitro, were used the ABTS and FRAP methods. Thus, it was possible to observe that the aqueous extract of artichoke constituted a promising source of phenolic compounds and the most efficient solvent in the extraction was the aqueous methanol solution 70%. The light was the condition that caused greater degradation of these, considering the storage time of the extract (35 days). Under cooling and in the absence of light the extracts kept the stability of phenolics compounds and the antioxidant capacity.