| Summary: | Marine macroalgae are considered to be interesting for food in Western countries and an important supply of novel natural bioactive compounds. Among these are polar lipids such as glycolipids, betaine lipids and phospholipids recognized as high valued lipids for nutrition and as functional ingredient with recognized health benefits. Its biosynthesis depends on several environmental factors such as seasonality, nutrition and habitat, increasing the structural complexity of macroalga lipidome, so that its identification is a current challenge. Mass spectrometry (MS) is a promising tool successfully applied in the study of lipidomic signature of distinct organisms, which can be extended to identify the hundreds of species in the lipidome of macroalgae, and allow them to finally be explored as potential source of lipids. In this work we aim to identify the lipidome of macroalgae representative of Chlorophyta (Codium tomentosum), Rhodophyta (Gracilaria sp. and Porphyra dioica) and Ochrophyta (Fucus vesiculosus). These algae thrive in the Portuguese coast but are recently being cultivated on an integrated multitrophic aquaculture system (IMTA). The characterization of the lipidome will be performed by using mass spectrometry analysis tools coupled to chromatographic methods. We aim to evaluate the bioactive properties of the polar lipids from macroalgae fostering the potential application of these compounds in function of its biological properties as anti-inflammatory and antiproliferative/antitumor agents. The main goals of this project were achieved after the characterization by using HILIC–MS and MS/MS approaches of the lipid extracts carrying on different extraction protocols. The results of this study allowed to identify about 238 molecular species distributed by twelve classes in the macroalgae Codium tomentosum, 147 molecular species in fourteen classes in Gracilaria sp., 110 molecular species in fourteen classes in Porphyra dioica and 181 molecular species distributed by seventeen classes in Fucus vesiculosus. Overall, the lipidome of these macroalgae included GLs monogalactosyl diacylglycerol (MGDG), digalactosyl diacylglycerol (DGDG), sulfoquinovosyl diacylglycerol (SQDG) and its lyso-form (SQMG); phosphatidylcholine (PC) and lyso-PC, phosphatidylglycerol (PG), lyso-PG (LPG), phosphatidic acid (PA), phosphatidylinositol (PI) and betaines (diacylglyceryl trimethyl-homoserine, DGTS). Green macroalgae may be differentiated by the predominance of molecular species including C16 – C20, polyunsaturated fatty acids (PUFA) such as 16:3, 18:3 and 20:5 from n-3 FA family. It contains several molecular species belonging to GLs and betaines including monoacylglyceryl trimethylhomoserine (MGTS), never reported before in the lipidome of macroalga. Red macroalgae are differentiated by molecular species that incorporate C20 FA chains of n-3 and n-6 families, mainly reflected on the composition of GLs.
|
|---|