Short Lecture 2 “The establishment of an analytical database of algal bromophenols and phytochemical characterization of the red alga Vertebrata lanosa”

Since the first description of algal bromophenols a wide array of structurally diverse brominated natural products has been isolated from green, brown and red algae [1]. As very few of these natural products are commercially available, isolation is almost always necessary for biological activity testing. One of the challenges during targeted isolation is the identification of the desired compounds via LC-MS in crude extracts or fractions, justifying the need for a comprehensive database of all known algal bromophenols and their analytical features (UV absorption maxima, MS fragmentation patterns, theoretical and reported adducts, species occurrence). We therefore established a database encompassing all bromophenols of algal origin published until now, including their analytical properties. Based on this database, a phytochemical analysis of a methanolic extract from Vertebrata lanosa (L.) T. A. Christensen (Rhodomelaceae) was conducted, a red alga with popular use in cosmetics [2] or as food [3]. This led to the isolation of 18 compounds, four of which have not been reported for V. lanosa previously and five are new natural products. Most of the isolated compounds were common lanosol derived bromophenols, however, also four novel bromotyrosine derivatives (3-bromo-5-sulfotyrosine, 3,5-dibromotyrosine, 3-bromo-6-lanosyltyrosine, 3-(6-lanosyllanosol)-tyrosine) could be isolated. Further, dibromophenylacetic acid methyl ester was isolated from this alga for the first time. In addition to the bromophenols, four acyl glycerogalactosides including one new compound (eicosapentaenoic acid 3′-[(6′′-O-α-galactosyl-β-D-galactosyl)]-1′-glycerol ester) were obtained.

Overall, the newly established database provided a useful tool to identify new bromophenols in V. lanosa and may aid future phytochemical studies in red algae.

• References

• 1 Jesus A, Correia-da-Silva M, Afonso C. et al. Isolation and potential biological applications of haloaryl secondary metabolites from macroalgae. Marine Drugs 2019; 17: 1-19
• 2 Leandro A, Pereira L, Gonçalves AMM. Diverse Applications of Marine Macroalgae. Marine Drugs 2019; 18
• 3 Bjordal MV, Jensen KH, Sjøtun K. A field study of the edible red alga Vertebrata lanosa (Rhodophyta). Journal of Applied Phycology 2020; 32: 671-681

Publikationsverlauf

Artikel online veröffentlicht:
12. Dezember 2022