Mycosporine-like amino acids (MAAs) have gained considerable attention as highly active photoprotective candidates for human sunscreens. However, more studies are necessary to evaluate the extraction efficiency of these metabolites in solvents compatible with cosmetics and their subsequent analysis by HPLC. In the present study, MAA extraction using distilled water and 20% methanol in four Rhodophyta was investigated. Different re-dissolution solvents and a C8 and C18 columns were tested for the HPLC analysis. Porphyra-334, shinorine, palythine, palythine-serine, asterina-330, and palythinol were identified by HPLC/ESI-MS.These MAAs were better isolated with the C8 column and using methanol as re-dissolution solvents. Regarding total MAAs concentrations, no differences between the two solvents were found. The highest values were observed injecting them directly in the HPLC. According to these results, distilled water could be an excellent extraction solvent in the production of MAAs extracts and quantification of their total concentrations for different uses in the industry. Nevertheless, the extraction of MAAs using 20% methanol and re-dissolution in pure methanol after dryness is the best option to characterize and identify the most common MAAs in these red algae. Our results entail important implications regarding the use of red macroalgae as promising candidates as environment-friendly sources of natural sunscreens.
Keywords: HPLC column; Rhodophyta; mycosporine-like amino acids; photoprotection; re-dissolution solvent.