Isolation and Characterization of Fucoidans from Five Brown Algae and Evaluation of Their Antioxidant Activity

In this study, we evaluated the chemical property and antioxidant activity of fucoidans isolated from brown algae, Laminaria japonica (LJF), Lessonia nigrescens (LNF), Lessonia trabeculata (LTF), Ascophyllum mackaii (AMF), and Ecklonia maxima (EMF). LJF was less in sulfate content (14.16%) and more in galactose and mannose content (1.08 and 0.68) than the documented early. EMF contained 20%-30% of sulfate and fucose, 0.97 in molar ratio which was lower than that of sulfate to other four fucoidans (1.21-1.41). AMF (162 kDa) and EMF (150 kDa) were the first two largest in molecular weight, which were followed by LJP (126 kDa), LNF (113 kDa) and LTF (105 kDa). The fucoidans isolated these algae showed a wide range of antioxidant activity in vitro. It was found that the reducing power of the isolated fucoidans was positively correlated with their sulfate content and molecular weight. In addition, LNF and LTF at low concentrations exhibited high superoxide and hydroxyl radical scavenging activity. This demonstrated that low molecular weight fucoidans may perform a high antioxidant activity.