Evaluation of the Effects of Fucoidans from Fucus Species and Laminaria hyperborea against Oxidative Stress and Iron-Dependent Cell Death.

Inga Hellige,Johann Roider,Georg Kopplin,Sandesh Neupane,Alexa Klettner,Signe Ptak,Susanne Alban,Marietta Zille,Sarah Apitz,Philipp Dörschmann,Xavier Fretté

doi:10.3390/md19100557

Abstract

Fucoidans are algal polysaccharides that exhibit protective properties against oxidative stress. The aim of this study was to investigate different fucoidans from brown seaweeds for their ability to protect against iron-dependent oxidative stress (ferroptosis), a main hallmark of retinal and brain diseases, including hemorrhage. We investigated five new high-molecular weight fucoidan extracts from Fucus vesiculosus, F. serratus, and F. distichus subsp. evanescens, a previously published Laminaria hyperborean extract, and commercially available extracts from F. vesiculosus and Undaria pinnatifida. We induced oxidative stress by glutathione depletion (erastin) and H2O2 in four retinal and neuronal cell lines as well as primary cortical neurons. Only extracts from F. serratus, F. distichus subsp. evanescens, and Laminaria hyperborea were partially protective against erastin-induced cell death in ARPE-19 and OMM-1 cells, while none of the extracts showed beneficial effects in neuronal cells. Protective fucoidans also attenuated the decrease in protein levels of the antioxidant enzyme GPX4, a key regulator of ferroptosis. This comprehensive analysis demonstrates that the antioxidant abilities of fucoidans may be cell type-specific, besides depending on the algal species and extraction method. Future studies are needed to further characterize the health-benefiting effects of fucoidans and to determine the exact mechanism underlying their antioxidative abilities.

Highlights

Fucoidans, or sulfated fucans, are polysaccharides of algae cell walls containing fucose sugar and sulfate ester groups
FV1 consisted of a considerable amount of glucose (34.2%), which may represent the co-extracted laminarin in the fucoidan sample [11], while FV2 consisted of a remarkable amount of xylose (19.8%)
We characterized novel fucoidan extracts from different brown algae species and with different chemical properties. We demonstrated that they exert differential protective effects in ARPE-19 and OMM-1 cells exposed to iron-dependent oxidative stress induced by erastin, while none of the assessed extracts was protective in neuronal ferroptosis

Summary

Introduction

Sulfated fucans, are polysaccharides of algae cell walls containing fucose sugar and sulfate ester groups. They are important for the integrity of the algae cell wall and fend off pathogens and other harsh environmental effects of the ocean and prevent dehydration [1,2]. They exhibit many different biological activities that depend on the origin of the extract, harvest time, the extraction process, chemical composition, structure, and size [3,4,5,6]. High-molecular weight fucoidans have been demonstrated to reduce oxidative stress [13,14]

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