Antioxidant Properties of Polysaccharide from the Brown Seaweed Sargassum graminifolium (Turn.), and Its Effects on Calcium Oxalate Crystallization

Abstract

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 (IC 50 = 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.Keywords: calcium oxalate crystallization; antioxidant; polysaccharide; Sargassum graminifolium OPEN ACCESSMar. Drugs 2012, 10 120 Abbreviations SGP, polysaccharide from Sargassum graminifolium; IR, infrared spectrum; DPPH, 1,1-diphenyl-2-picrylhydrazyl free radical; Ox, oxalate; CaOx, calcium oxalate; OD, optical density; S N , maximum increase of optical density with time; S A , rate of aggregation derived from the maximum decrease in optical density; t max , maximum time; COM, Calcium oxalate monohydrate; COD, Calcium oxalate dehydrate; COT, Calcium oxalate trihydrate.

Optimized ultrasonic-assisted extraction of polysaccharides fromCyclina sinensisand evaluation of antioxidant activities in vitro

“…Whereas, the efficacy was far lower than that of the reference ascorbic acid (99.54 ± 0.09%) at the concentration (1.0 mg/mL), the EC 50 of ascorbic acid was 0.18 mg/mL. The EC 50 of PCS were 0.11, 12.50 and 2.50 mg/mL for DPPH, hydroxyl and superoxide radical, which are similar to the EC 50 values of polysaccharides from Inonotus obliquus and Sargassum graminifolium (Mu et al, 2012;Zhang, Wu, Wang, & Lan, 2012). The results obtained from the test systems suggested that PCS have significant antioxidant activities, and the effects increase with increasing concentration of PCS, which are in accordance with the previous reports (Jiang, Wang, Liu, Gan, & Zeng, 2011).…”

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“…The radical scavenging effect on DPPH of compounds 1 – 5 were determined according to previously reported methods [27,28], and 2,6-ditertbutyl-4-methylphenol was used as a positive control.…”