Effects of molecular weight and ratio of guluronic acid to mannuronic acid on the antioxidant properties of sodium alginate fractions prepared by radiation-induced degradation

In this study the effects of the molecular weight and ratio of guluronic acid (G) to mannuronic acid (M) G/M of some sodium alginate (NaAlg) fractions on their antioxidative properties were investigated Low-molecular-weight-fractions with various G/M were prepared by gamma radiation-induced degradation of NaAlg Change in their molecular weight was monitored Antioxidant properties of the fractions with various molecular weight and G/M were evaluated by determining the scavenging ability of 1 1-diphenyl-2-picrylhydrazyl free radical (DPPH) 50% inhibition concentrations of the 50 kGy-irradiated NaAlgs having molecular weights of 20 5 17 7 and 16 0 kDa were found to be 11 0 18 0 and 24 0 mg/ml respectively whereas the fractions of the same molecular weight with a lower G/M exhibited a better DPPH scavenging activity The results demonstrated that its molecular weight and G/M were Important factors in controlling the antioxidant properties of NaAlg (C) 2010 Elsevier Ltd All rights reserved