Density Functional Theory Studies on the Antioxidant Mechanism of Fucoidan Polysaccharide Extracted from Seaweed

Fucoidans, sulfated polysaccharides that are isolated from brown seaweed, have strong antioxidant activity. The antioxidant activity of Fucoidan was reviewed through the main antioxidant mechanism of Hydrogen Atom Transfer (HAT) by density functional theory (DFT) at the level of DFT/B3LYP/6-31G** theory. The discriminant thermochemical properties, such as the bond dissociation enthalpy in the solution phase, were calculated. Analysis of values of bond dissociation enthalpy (BDE) and determination of localization probabilities clearly shows the importance of the 4-OH group in antioxidant reactivity.