Preparation, chemical characterization and antioxidant activity of crude polysaccharide and oligosaccharide extracted from the ascidian Styela clava

The crude polysaccharide (PS) and oligosaccharide (OS) were isolated from the ascidian Styela clava. The chemical and physical characteristics of the two saccharides were determined by IR spectrophotometer and several chemical methods, and their antioxidant activities were appraised by various in vitro assay systems, including the scavenging activity of free and hydroxyl radicals and reducing power. The EC50 of PS and OS against hydroxyl radical was 4.35 and 5.82 mg/mL, while EC50 on DPPH radicals was 4.95 and 0.84 mg/mL, respectively. The results indicated that both crude polysaccharide and oligosaccharide extracted from Styela clava had antioxidant activities and could be explored as novel potential antioxidants.