title: Antioxidant properties of polysaccharide from the brown seaweed Sargassum graminifolium (Turn.), and its effects on calcium oxalate crystallization.
abstract: We investigated the effects of polysaccharides from the brown seaweed Sargassum graminifolium (Turn.) (SGP) on calcium oxalate crystallization, and determined its antioxidant activities. To examine the effects of SGP on calcium oxalate crystallization, we monitored nucleation and aggregation of calcium oxalate monohydrate crystals, using trisodium citrate as a positive control. We assessed antioxidant activities of SGP by determining its reducing power, its ability to scavenge superoxide radicals, and its activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The nucleation inhibition ratio of trisodium citrate and SGP was 58.5 and 69.2%, respectively, and crystal aggregation was inhibited by 71.4 and 76.8%, respectively. Increasing concentrations of SGP resulted in increased scavenging of superoxide anions and DPPH radicals (IC₅₀ = 1.9 and 0.6 mg/mL, respectively). These results suggest that SGP could be a candidate for treating urinary stones because of its ability to inhibit calcium oxalate crystallization and its antioxidant properties.
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, Research Center of Analysis and Testing, East China University of Science and Technology, Shanghai 200237, China.|College of Food Science and Technology, Institutes of Marine Sciences, Shanghai Ocean University, Shanghai 201306, China.
authors.forename: Chao-Yan
authors.initials: CY
authors.lastname: Zhang
authors.affiliation: College of Food Science and Technology, Institutes of Marine Sciences, Shanghai Ocean University, Shanghai 201306, China.
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Wu
authors.affiliation: College of Food Science and Technology, Institutes of Marine Sciences, Shanghai Ocean University, Shanghai 201306, China.
authors.forename: Jue
authors.initials: J
authors.lastname: Wang
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, Research Center of Analysis and Testing, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Min-Bo
authors.initials: MB
authors.lastname: Lan
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D001713:Biphenyl Compounds / Q000737:chemistry; D002129:Calcium Oxalate / Q000737:chemistry*; D003460:Crystallization; D006801:Humans; D010851:Picrates / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry / Q000494:pharmacology*; D044647:Sargassum / Q000737:chemistry*; D014545:Urinary Calculi / Q000188:drug therapy
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D010851:Picrates; D011134:Polysaccharides; D002129:Calcium Oxalate; C004931:1,1-diphenyl-2-picrylhydrazyl