Analysis and bioprospecting of polyphenols from Laminaria hyperborea for applications as Life Science Ingredients

In the final phase of this project, the focus was on an in-depth chemical characterization of the abundant polyphenolic compounds, found in the brown seaweed Laminaria hyperborea (L.Hyp). After extraction and quantification methods were optimized in an earlier phase of the project, the extract was further purified using flash chromatography in semi-preparative scale and separated into fractions. Several fractions of phenolic compounds but also carotenoids and aliphatic acids were obtained. These fractions were analysed through high resolution mass spectrometry (HR LC-MS) as well as NMR, IR- and Raman spectroscopy. Among the most important findings were: (I) Most phenolic compounds in L.Hyp are of low molecular weight (96% below 800 Da). (II) The carotenoid fraction contains almost exclusively fucoxanthin. (III) Eleven phlorotannins and phenolic acids were identified (e.g., salicylic acid, veratric acid, 5-carboxyvanillic acid, sinapic acid, 5-sulfosalicylic acid, vanillic acid 4-sulfate, dihydrocaffeic acid 3-sulfate). (IV) A high prevalence of sulfated polyphenols was found in L.Hyp and a sulfated dimer phlorotannin was characterized for the first time. A quantitative and qualitative assessment of polyphenolic compounds in Laminaria hyperborea has been achieved.

This project investigated the extraction, purification and characterization of polyphenols from Laminaria hyperborea (L.Hyp). Polyphenols are known for their many bioactive properties such as antioxidative, antimicrobial, antidiabetic as well as properties like anti-aging and UV-protection. A key development in this project is an accurate method for polyphenol quantification by using NMR spectroscopy, supporting and surpassing the commonly used TPC assay. The method facilitates targeting of several high value market segments and applications for polyphenols. A comprehensive understanding of the polyphenol composition of L.Hyp was achieved. Eleven polyphenolic components have been identified. Among them are sulfated phlorotannins, exclusively present in marine biomass. Sulfated phlorotannins are a novel group of bioactive ingredients, relevant for the pharmaceutical, cosmetic and food industry. Furthermore, It was revealed that the carotenoid fraction of L.Hyp is almost exclusively comprised of fucoxanthin, another high value compound utilized in the medical industry and as a dietary supplement. Lastly this project optimized extraction methods for polyphenols on a laboratory scale and purification methods at the semi-preparative scale. The aims are to generate purified phenolic extracts as well as to harness hitherto underutilized side-streams from the biorefinery of L.Hyp. A quantitative and qualitative assessment of the polyphenolic compounds in Laminaria hyperborea was achieved and a process line for an upscaled extraction of polyphenolic compounds has been developed.

Det overordnede målet med Nærings-Ph.D.-prosjektet er å skaffe ny informasjon, på eksakt molekylnivå, om polyfenoler i Laminaria hyperborea for bruk i næringsmiddel-, fôr- og helsekontekst ved å optimalisere ekstraksjons-, isolasjons-, identifikasjons- og kvantifiseringsmetoder for disse forbindelsene. Prosjektet vil bygge på etablert kompetanse innen naturlig produktfunn, spesielt i polyfenoler, i Marine Natural Product (MNP) Chemistry gruppe ved Institutt for Kjemi (UiB). Prosjektet vil benytte den analytiske plattform ved instituttet. Ph.D.-prosjektet vil også søke etter bioaktive egenskaper av isolerte komponenter for å fullt ut kunne vurdere deres bioprospekteringspotensial i MNP-gruppenes nettverk. Fase I i Ph.D.-prosjektet vil fokusere på utvinningstrinnene til Alginor ASA (Haugesund) for å evaluere prosessutfallet. Fase II vil fokusere på kvantifisering og identifisering av polyfenoler fra ekstraksjonstrinnene, og Fase III vil fokusere på ny informasjon om polyfenoler fra Laminaria hyperborea.