gms | German Medical Science

The ABC Conference: Algae Bioactive Compounds – from research to innovation

The project is funded by Interreg Deutschland-Danmark with means from the European Regional Development Fund.

25. - 26.08.2020, Kiel, Germany (online conference)

Effects of fucoidans on oxidative stress protection, VEGF secretion and functions in ocular cells, depending on the brown algae species, molecular weight and purity of the extract

Meeting Abstract

  • presenting/speaker Philipp Dörschmann - University Medical Centre Kiel, Clinic for Ophthalmology, Kiel, Germany
  • Georg Kopplin - Alginor ASA Haugesund, Denmark
  • Maria Dalgaard Mikkelsen - Technical University of Denmark Lyngby, Denmark
  • Anne S. Meyer - Technical University of Denmark Lyngby, Denmark
  • Johann Roider - University Medical Centre Kiel, Clinic for Ophthalmology, Kiel, Germany
  • Alexa Klettner - University Medical Centre Kiel, Clinic for Ophthalmology, Kiel, Germany

The FucoSan consortium. The ABC Conference: Algae Bioactive Compounds – from research to innovation. Kiel, 25.-26.08.2020. Düsseldorf: German Medical Science GMS Publishing House; 2020. Doc20fucosan12

doi: 10.3205/20fucosan12, urn:nbn:de:0183-20fucosan125

Published: October 7, 2020

© 2020 Dörschmann et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at



Background: Fucoidans, polysaccharides from brown algae, can have various effects depending on their chemical composition and origin. VEGF-lowering (vascular endothelial growth factor), antioxidative and anti-inflammatory properties are described. To find the best fucoidan for a possible application in the treatment of age-related macular degeneration (AMD), fucoidans from two brown algae species with different molecular sizes and degrees of purity, were tested.

Methods: Fucoidans from Saccharina latissima (SL) and Laminaria hyperborea (LH) were obtained by enzyme-assisted extraction or hot water extraction, respectively, with subsequent chemical treatments. The SL extracts were separated into three fractions with ion exchange chromatography, making four SL extracts with different degrees of purity (fucose content). Three fractions of LH-fucoidan of different size were obtained by acid treatment (26.9, 499 and 1,548 kDa). Concentrations between 1-100 µg/ml were tested. Cell models were the uveal melanoma cell line OMM-1, the RPE cell line ARPE-19, and primary porcine RPE (retinal pigment epithelium). Cell viability was investigated with MTS assay (3-(4,5-Dimethylthiazol-2-yl)5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium). Oxidative stress was induced with H2O2 (OMM-1) or tert-butyl hydroperoxide (TBHP) (ARPE-19). VEGF, IL-6 (interleukin 6) and IL-8 (interleukin 8) secretion was detected in ELISA (enzyme-linked immunosorbent assay). Wound healing ability was assessed by scratch assay. RPE65 expression was investigated by Western Blot. The expression of AMD and inflammation relevant genes after LH treatment was investigated by real-time PCR (polymerase chain reaction).

Results: SL and LH fucoidans are non-toxic for ARPE-19 and RPE cells. The higher the molecular weight of the LH-fucoidans or the higher the fucose content (purity) of the SL-fucoidans, the stronger the VEGF inhibition. The largest LH-fucoidan and the second fraction of SL (highest fucose content) showed protective effects against H2O2. Furthermore, the LH-fucoidan with the highest molecular weight and the second SL fraction reduced the secretion of IL-8. Wound healing was slightly inhibited by SL but not LH after 48 h. RPE65 expression was decreased by SL but not LH. The expression of IL-6 and MMP9 (matrix metallopeptidase 9) was decreased by LH.

Summary: The results of the fucoidans from SL and LH suggest that high molecular weight and high purity improve antiangiogenic and anti-inflammatory activities. Antioxidant properties of the large LH and SL fucoidans could be demonstrated. Some slight effects on RPE physiological function could be seen with SL, but not LH extracts. Large and pure fucoidans of these algae species seem to be suitable for further development of a therapy for AMD. Further research is warranted to fully elucidate their effects.