title: 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.
abstract: 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 24.0mg/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.
authors.affiliation: Hacettepe University, Department of Chemistry, Polymer Chemistry Division, Beytepe, 06800 Ankara, Turkey. msen@hacettepe.edu.tr
authors.forename: Murat
authors.initials: M
authors.lastname: Sen
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000975:Antioxidants / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000737:chemistry; D016166:Free Radical Scavengers / Q000138:chemical synthesis* / Q000737:chemistry; D005720:Gamma Rays; D006603:Hexuronic Acids / Q000737:chemistry*; D008970:Molecular Weight; D010851:Picrates / Q000737:chemistry
chemical_list: D000464:Alginates; D000975:Antioxidants; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D006603:Hexuronic Acids; D010851:Picrates; C007896:guluronic acid; C008324:mannuronic acid; C004931:1,1-diphenyl-2-picrylhydrazyl