Esterois de macroalgas Phaeophyceae da Antártica: extração e análise por métodos cromatográficos

Abstract

The Antarctic region is characterized by great diversity of Phaeophyceae macroalgae, however, to date, little information about the bioactive molecules present in these macroalgae is available in the current literature. This study proposed a new methodology for the extraction of sterols present in Desmarestia anceps brown macroalgae. The new method of extraction by ultrasound at room temperature, proved to be more efficient to extract these molecules compared to other methods described in the literature (extractions with magnetic stirring and microwave irradiation). The extracts obtained were analyzed by gas chromatography with flame ionization detection (GC/FID) and gas chromatography coupled with mass spectrometry (GC/MS), making possible the identification and quantification of seven sterols (brassicasterol, campesterol, cholesterol, ergosterol , stigmasterol, β-sitosterol and fucosterol) present in the macroalgae. The extraction methodology proved to be efficient when compared with the other proposed techniques, with extraction recovery rates obtained in 20 minutes and an amplitude of 40% in the extraction. The ultrasound extraction methodology proposed was applied in six species of brown macroalgae originating in the Antarctic: Adenocystis ultricularis, Ascoseira mirabilis, Cystosphaera jacquinotii, Desmarestia anceps, Desmarestia Antarctic and Hymantothallus grandifolius. The extracts were analyzed by high performance liquid chromatography coupled to mass spectrometry (LC-MS/MS), allowing the identification and quantification of sterols present in six brown macroalgae. Among the analyzed sterols, fucosterol presented the highest levels in the macroalgae, followed by stigmasterol and β-sitosterol. Campesterol was the sterol found in the lowest proportion in brown macroalgae. The macroalgae H. grandifolius exhibited the highest concentration of sterols and the algae D. Antarctic had the lowest concentration of sterols in its composition. The data obtained show that the sterol profile of Antarctica brown macroalgae is promising, for further isolation of these compounds with fucosterol, stigmasterol and β-sitosterol which have a great therapeutic and biological potential.