Initial evaluation of six different brown algae species as source for crude bioactive fucoidans

The fucose-containing sulfated polysaccharides (syn. fucoidans) from brown seaweeds exhibit multiple biological activities. The aim of the present study was to evaluate the suitability of crude fucoidans from six different brown algal species for further research and development. For this, fucoidans were extracted from Fucus vesiculosus (F.v.), F. serratus (F.s.), F. evanescens (F.e.), Dictyosiphon foeniculaceus (D.f.), Laminaria digitata (L.d.), and Saccharina latissima (S.l.) and compared concerning their yields, their basic characteristics, degree of sulfation (DS), molecular mass, monosaccharide composition, their contents of polyphenols, laminarin and protein as well as their radical-scavenging capacity, three exemplary bioactivities and their fluorescence intensity (FI) increasing effect on the sulfated glycan sensor Polymer-H. The activities positively correlated with the DS, fucose content and the FI of Polymer H, whereas the antioxidant capacity correlated with the coextracted polyphenols. The best predictive power for the activities showed to have the combination of FI of Polymer-H and DS, which can thus be used for an initial screening of algae extracts. D.f. turned out to be unsuitable as fucoidan source, as the extract had only a low DS (0.14) and fucose content (38.7%) as well as the weakest bioactivities. The fucoidans from S.l. and F.e., which had the fucose content, highest DS, purity and yield, exhibited the best activities and thus proved to be the fucoidans most suitable for further investigations.