Production and properties of mycosporine-like amino acids isolated from seaweeds

Abstract Mycosporine-like amino acids (MAAs) belong to a family of secondary metabolites produced by various organisms. However their occurrence is limited to some terrestrial organisms and they appear to be more frequent in marine organisms, such as cyanobacteria, algae and invertebrates. These photoprotective compounds have been isolated from various macroalgal species, mainly in Rhodophyta. Their chemical structure corresponds to polysubstituted aminocyclohexenone or aminocyclohexenimine derivatives substituted with a wide variety of functional groups, such as amino acids. The major role of MAAs in photoprotection against UV radiation has been demonstrated, and is linked to their chemical structure. It would appear however that some MAAs may also have various functions such as antioxidant or nitrogen source allowing the macroalgae adaptation to stressful environments. The biosynthesis of MAAs is suggested through two possible pathways, the shikimate or the pentose-phosphate, which involve the production of key precursors, deoxygadusol and gadusol. Taxonomically, they have been studied in the orders Ceramiales, Gigartinales, Gracilariales, and Bangiales. MAAs are isolated from natural biomass including wild or cultivated sources. Its concentration depends on quality and quantity irradiation, and on inorganic nitrogen availability. In some species, MAAs have been induced under culture conditions. Production of MAAs can be achieved by scaling up the macroalgae biomass, especially under IMTA systems followed by solid/liquid extraction. Because of the low extraction yield from natural sources, the need for large scale production and standard molecules for chemical analysis motivates the attempt at chemical synthesis. Chemical analysis of MAAs requires different techniques such as liquid chromatography (LC) or capillary electrophoresis for the separation and, mass spectrometry or nuclear magnetic resonance for the structural characterization. LC chromatography is mostly applied for the purification of MAAs. Various applications are herein outlined with special emphasis on anti-UV, antioxidant, anti-aging and anti-inflammatory.