Sterols in red macroalgae from antarctica: extraction and quantification by Gas Chromatography–Mass spectrometry

Abstract

Antarctica is considered a major reservoir of microorganisms and macroorganisms, including seaweed, which can biosynthesize secondary metabolites with unique structures and specific biological activities. Macroalgae are considered an interesting source of steroids, a class of metabolites involved in the control of membrane fluidity and permeability. This study reports the extraction and quantification of sterols in four red macroalgal species from Antarctica: Palmaria decipiens, Plocamium cartilagineum, Iridaea cordata, and Pyropia endiviifolia. The extraction of sterols involved alkaline hydrolysis from algal biomass. The quantification of cholesterol, brassicasterol, campesterol, stigmasterol, β-sitosterol, and fucosterol were performed by gas chromatography hyphenated with mass spectrometry (GC–MS). In general, 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 to 393.20 mg kg−1), brassicasterol (68.56 to 337.43 mg kg−1), campesterol (64.95 to 277.78 mg kg−1), and fucosterol (57.67 to 286.18 mg kg−1). Brassicasterol was not found in I. cordata, but it was identified in the other three samples. This work enriches the knowledge about the profile of steroids biosynthesized by Antarctic macroalgae and supports research to discover bioactive compounds with nutraceutical and pharmaceutical applications.