Antioxidant activity of fucose-containing sulfated polysaccharides obtained from Fucus evanescens by different extraction methods

The fucose-containing sulfated polysaccharides (FCSPs) from Fucus evanescens were obtained via different procedures: by hot acidic extraction and with aqueous calcium chloride solution, followed by separation FCSPs using anion-exchanging chromatography. Chemical characteristics of these polysaccharide fractions were determined. It was shown that extraction with aqueous calcium chloride solution provides a purified preparation of the FCSPs. The crude polysaccharide and its chromatography purified fractions obtained by this method have significantly lower contents of laminaran, uronic acids, and polyphenols in comparison with FCSPs obtained by hot acid extraction. All polysaccharides exhibited total antioxidant capacity and 1,1-diphenyl-2-pycrilhydrazyl (DPPH) radical-scavenging activity and low 2,2'-azino-bis 3-ethyl benzothiazoline-6-sulfuric acid (ABTS) radical-scavenging activity. A strong positive correlation between polyphenol content in FCSPs and their antioxidant activity was found. This fact may indicate that phenols play a key role in the previously described antioxidant capacity of FCSPs.