Polyunsaturated Fatty acids of marine macroalgae: potential for nutritional and pharmaceutical applications

Abstract

As mammals are unable to synthesize essential polyunsaturated fatty acids (PUFA), these compounds need to be taken in through diet. Nowadays, obtaining essential PUFA in diet is becoming increasingly difficult; therefore this work investigated the suitability of using macroalgae as novel dietary sources of PUFA. Hence, 17 macroalgal species from three different phyla (Chlorophyta, Phaeophyta and Rhodophyta) were analyzed and their fatty acid methyl esters (FAME) profile was assessed. Each phylum presented a characteristic fatty acid signature as evidenced by clustering of PUFA profiles of algae belonging to the same phylum in a Principal Components Analysis. The major PUFA detected in all phyla were C(18) and C(20), namely linoleic, arachidonic and eicosapentaenoic acids. The obtained data showed that rhodophytes and phaeophytes have higher concentrations of PUFA, particularly from the n-3 series, thereby being a better source of these compounds. Moreover, rhodophytes and phaeophytes presented "healthier" ∑n-6/∑n-3 and PUFA/saturated fatty acid ratios than chlorophytes. Ulva was an exception within the Chlorophyta, as it presented high concentrations of n-3 PUFA, α-linolenic acid in particular. In conclusion, macroalgae can be considered as a potential source for large-scale production of essential PUFA with wide applications in the nutraceutical and pharmacological industries.

Keywords: EPA; PUFA; marine macroalgae; nutrition.

Figure 1

Schematic representation of the n-3 and n-6 fatty acid biosynthetic pathway with the enzymes responsible for each step of desaturation/elongation depicted in gray boxes. The partial β-oxidation that results in docosapentaenoic acid (DPA) or docosahexaenoic acid (DHA) formation is highlighted in blue. Differences occurring at each step are marked red in the chemical structure. Adapted from Marszalek and Lodish [19].

Figure 2

Total FAME concentration of macroalgae from three different phyla (Chlorophyta, Phaeophyta and Rhodophyta). Error bars represent the standard deviation from four replicates.

Figure 3

PCA plot of the macroalgae fatty acid composition profiles showing the loadings on PC1 and PC2, representing 26.0% and 20.5% of the total variance of the data, respectively.

Figure 4

PCA of the fatty acid composition of macroalgae showing the data scores labeled by phylum. Green—Chlorophyta; Brown—Phaeophyta; Red—Rhodophyta.