Lipídeos de Microalgas Antárticas: Análises por Cromatografia Gasosa e Espectrometria de Massas e estudos preliminares das atividades antioxidante e antibacteriana

Abstract

Antarctica comprises a reservoir of microorganisms and macroorganisms, including macroalgae, known for their richness in phytochemicals. Macroalgae are considered a source of steroids and fatty acids, classes of metabolites involved in the fluidity and permeability of the membrane. This study aims to extract and quantify sterols from four red Antarctic macroalgae: Palmaria decipiens, Plocamium cartilagineum, Iridaea cordata and Pyropia endiviifolia, in which the extraction of sterols involves alkaline hydrolysis of algae biomass. The quantification of cholesterol, brassicasterol, campesterol, stigmasterol, β- sitosterol and fucosterol was performed by gas chromatography coupled with mass spectrometry (GC-MS). The lipid profile was also evaluated using chromatographic and spectroscopic analyzes of five Antarctic macroalgae, Adenocystis utricularis, Desmarestia confervoides, Curdiea racovitzae, Myriogramme manginii and Ulva intestinales, as well as antioxidant and antibacterial activities. In the quantification of steroids, cholesterol was the most abundant compound (216.32 to 3195.69 mg kg-1), followed by β-sitosterol (131.42 to 654.18 mg kg-1), stigmasterol (68.35 at 393.20 mg kg-1), brassicasterol (68.56 to 337.43 mg kg-1), campesterol (64.95 to 277.78 mg kg-1-1) and fucosterol (57.67 to 286.18 mg kg-1). Brassicasterol was not found in I. cordata, but was identified in the other three samples. As a result of the lipid profile of the five macroalgae, 31 components were identified, comprising mainly fatty acids (48.73 -331.91 mg.Kg-1), sterols (14.74 - 321.25 mg.kg-1and alcohols) (13.07 - 91.87 mg.kg-1). In addition, Desmarestia confervoides showed an antioxidant activity of 86.03% inhibition of the DPPH radical at 1 mg.mL-1. The antibacterial evaluation showed that extracts Ulva intestinales, Curdiea racovitzae and Adenocystis utricularis inhibited the growth of Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923) and Salmonella typhimurium (ATCC 14028) in concentrations of 1.5 to 6 mg.mL-1. evaluated in this study have potential in chemical compounds that include representatives of lipids and, in addition, have promising activities as antioxidant and antibacterial agents that can be applied by the pharmaceutical, biotechnological and food industries.