title: Antioxidant capacities of mannans and glucans are related to their susceptibility of free radical degradation.
abstract: Microbial and plant polysaccharides in nature are frequently exposed to oxidative burst. They may act as antioxidants buffering the radical attack. This paper presents antioxidant properties of prepared yeast mannans, commercial β-glucans as well as the chemically prepared carboxymethylated β-glucan (CM-glucan). The hydroxyl radical antioxidant assay and the DPPH radical-scavenging assay were used. Yeast mannans and β-glucans (1.6 mg mL(-1)) showed antioxidant capacities against OH(·) up to 14.1%, while CM-glucan was significantly higher antioxidant (65.4%). In the DPPH(·) assay, the antioxidant capacities of yeast mannans and β-glucans (1.0 mg mL(-1)) were lower and reached up to ~6.5%. All polysaccharides tested were effectively degraded by OH(·) and the presence of salicylate considerably inhibited their degradation. Measure of Fe(2+) chelation revealed less than 13.1% effectivity for all polysaccharides. In all antioxidant and degradation experiments the yeast mannans showed very similar results to commercial β-glucans. The antioxidant capacities of polysaccharides may be assessed by simple HPLC monitoring.
authors.affiliation: Institute of Chemistry, Department of Immunochemistry of Glycoconjugates, Centre of Excellence Glycomed, Slovak Academy of Sciences, Dúbravská cesta 9, 84538 Bratislava, Slovakia. Electronic address: eva.machova@savba.sk.
authors.forename: Eva
authors.initials: E
authors.lastname: Machová
authors.forename: Slavomír
authors.initials: S
authors.lastname: Bystrický
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D001713:Biphenyl Compounds / Q000037:antagonists & inhibitors; D005609:Free Radicals / Q000037:antagonists & inhibitors* / Q000737:chemistry; D005936:Glucans / Q000737:chemistry / Q000494:pharmacology*; D017665:Hydroxyl Radical / Q000037:antagonists & inhibitors; D007502:Iron Chelating Agents / Q000737:chemistry / Q000494:pharmacology; D008351:Mannans / Q000737:chemistry / Q000494:pharmacology*; D010851:Picrates / Q000037:antagonists & inhibitors; D011134:Polysaccharides / Q000737:chemistry / Q000494:pharmacology; D015003:Yeasts / Q000737:chemistry
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D005609:Free Radicals; D005936:Glucans; D007502:Iron Chelating Agents; D008351:Mannans; D010851:Picrates; D011134:Polysaccharides; D017665:Hydroxyl Radical; C004931:1,1-diphenyl-2-picrylhydrazyl
keywords: Antioxidant; DPPH; Glucan; Mannan; OH; Radical degradation