A New Look for the Red Macroalga Palmaria palmata: A Seafood with Polar Lipids Rich in EPA and with Antioxidant Properties

Abstract

Palmaria palmata is an edible red macroalga widely used for human consumption and valued for its high protein value. Despite its low total lipid content, it is rich in eicosapentaenoic acid (EPA). This seaweed has been scarcely explored with regard to its lipid composition. The polar lipids of seaweeds are nowadays recognized as important phytochemicals contributing to their add value valorization and providing support for claims of potential health benefits. The present study aimed to disclose the polar lipid profile of P. palmata, farmed in an integrated multi-trophic aquaculture (IMTA) through modern lipidomic approaches using high-resolution LC-MS and MS/MS and to screen for the antioxidant properties of this red macroalga. A total of 143 molecular species of lipids were identified, belonging to several classes of polar lipids, such as glycolipids, phospholipids, and betaine lipids. It is noteworthy that the most abundant lipid species in each class were esterified with eicosapentaenoic acid (EPA), accounting for more than 50% of the lipid content. The polar lipid extract rich in EPA showed antioxidant activity with an inhibition concentration (IC) of IC30 = 171 ± 19.8 µg/mL for α,α-diphenyl-β-picrylhydrazyl radical (DPPH●) and IC50 = 26.2 ± 0.1 µg/mL for 2,20-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS●+). Overall, this study highlights that P. palmata farmed in an IMTA framework can be a sustainable source of beneficial lipids with antioxidant activity. Moreover, this red macroalga can be exploited for future applications as a source of lipids rich in EPA for food and feed, nutraceuticals, and cosmetics.

Domesticated Populations of Codium tomentosum Display Lipid Extracts with Lower Seasonal Shifts than Conspecifics from the Wild—Relevance for Biotechnological Applications of this Green Seaweed

“…Additionally, algae have evolved protective mechanisms against oxidation that promote the production of metabolites to re-establish cell metabolism, which can modify the antioxidant system to correct cellular redox balance [18,52]. Products of algal metabolism have been the target of multiple studies due to their bioactivity [2,4,11,12,46]. Several authors highlight the role of secondary metabolites in the presence of bioactive compounds, such as phenolics [4,13].…”

“…Several authors highlight the role of secondary metabolites in the presence of bioactive compounds, such as phenolics [4,13]. Nevertheless, some compounds flagged by researchers due to their bioactivity are paramount in algal metabolism, such as glycolipids, pigments, or PUFAS [1,2,[10][11][12]46]. Total lipid extracts contain several compounds with putative bioactivity, such as glycolipids and fatty acids (e.g., linoleic acid, C18:2 n-6), oxylipins, or pigments [10,46,53].…”

“…Oceans host an impressive wealth of life forms that harbor unique biochemical diversity. Several studies have recently confirmed the high potential of marine organisms as source of bioactive compounds, with interest for the food, fodder, pharmaceutical, biomedical and cosmetic industries [1][2][3][4]. Algae represent some of the most abundant organisms in the marine environment, playing a relevant ecological role on a global scale, as O 2 producers, CO 2 sequesters, primary producers, nutrient recycling, and micro-ecosystems.…”

“…Edible seaweeds are known to be rich in bioactive metabolites, some of them not present in land plants [5]. These metabolites have relevant bioactivities, such as antioxidants [1,2], antimicrobial [4], antigenotoxic [6], and anti-tumorigenic activities [7], holding great potential for biotechnological applications, as food additives [8] and for the production of bioplastics [9], among other high-end uses. Bioactivity has been identified in compounds that are essential for macroalgae metabolism, such as lipids and pigments [10][11][12], but also in products originating from their secondary metabolism [4,13].…”

Valuing Bioactive Lipids from Green, Red and Brown Macroalgae from Aquaculture, to Foster Functionality and Biotechnological Applications

“…The most well-studied macroalgae bioactive compounds include abundant molecules such as polysaccharides and peptides, although minor constituents, such as alkaloids and lipids, have also been recognized for their nutritional and bioactive values [ 17 , 18 ]. Even though macroalgae have a low lipid content (which is variable among macroalgal species [ 19 , 20 , 21 , 22 , 23 ]), these compounds are recognized as an important source of polyunsaturated fatty acids (PUFA) including long-chain omega-3 FA, such as α-linolenic acid (18:3 n -3), eicosapentaenoic acid (20:5 n -3) and docosahexaenoic acid (22:6 n -3), that have been addressed as essential modulators to reduce the risk of cancer and cardiovascular diseases [ 24 ]. Omega-3 PUFA mostly occurs in their esterified form in polar lipids, mainly as glycolipids and phospholipids, which were recently identified in edible green, red and brown macroalgae species Ulva rigida, Codium tomentosum, Gracilaria sp.…”