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Showing 2 results for Brown Seaweed
Volume 6, Issue 2 (9-2017)
Abstract
The extraction of hydrocolloids from seaweeds is associated with production of secondary metabolites during pretreatment step. In this study, the antioxidant properties were evaluated for secondary metabolites from brown seaweed S. angustifolium. The crude extract obtained by 80% ethanol for four hours and then partitioned using hexane, chloroform, ethyl acetate and water. The extraction yield was found to be 4% for crude extract and varied between 2.8-43% for fractions. The evaluation of antioxidant properties revealed a successful solvent fractionation in portioning antioxidant compounds. Among various fractions, ethyl acetate exhibited the highest activity in DPPH radical scavenging (75.78%), ABTS radical scavenging (88.92%), reducing power (67.54%) and total antioxidant (0.34 Abs) capacities. The highest amount of phenolic contents was found in ethyl acetate fraction (277.86 mg/ TA in extract) while the lowest amount was in aqueous fraction (21.36 mg/ TA in extract). The highest correlation (R2 = 0.88) was observed between total phenolic content and total antioxidant activity. Overall, the results of current study show that ethanol extract of S. angustifolium contains major bioactive compounds suggesting its potential application in food industry as a natural antioxidant.
S. Mashjoor , M. Alishahi , Z. Tulaby Dezfuly ,
Volume 9, Issue 3 (9-2018)
Abstract
Aims: The bio-toxicity of silver nanoparticles (AgNPs) in the aquatic ecosystem and the detection of lethal concentrations of this material are of importance. The aim of this study was in vivo comparative toxicity of silver nanoparticles and bio-productivity in zebrafish (Danio rerio) in embryo and adult stages.
Materials and Methods: The present experimental study was carried out on 30 fertilized eggs and 30 adult zebrafish and the effects of chemical and bio-productivity of AgNPs were evaluated by brown seaweed (Sargassum boveanum) in evolutionary stages of the embryo and adult zebrafish with a control group and in incremental concentrations. The mortality rate was recorded at 24, 48, 72, and 96 hours after exposure and the data were analyzed by EPA Probit Analysis 1.5 and SPSS 19 softwares, using one-way analysis of variance and Duncan's multiple range test.
Findings: The toxicity of both types of AgNPs in both evolutionary stages was increased with increasing concentrations and time (p<0.05). After 96 hours, the lethal concentration 50 (LC50) in adult fish was 0.788mg/l for chemical AgNPs and 0.409mg/l for bio-produced AgNPs. Mortality rate at the highest concentration (3mg/l) of AgNPs at 72 and 96 hours in all groups was 100%.
Conclusion: Comparison of the toxicity result showed that the biosynthesis form of AgNPs is more toxic potential than chemical form of AgNPs. It seems the sensitivity of embryo stage to both of silver nanoparticles more than to mature stage.
