Synthesis Of Selenium Nanoparticles In The Presence Of Oyster Polysaccharides And The Antioxidant Activity

Selenium is a necessary trace element for human body. It is a vital component ofmultiple enzymes, for example, glutathione peroxidase, thioredoxin reductase anddeiodinase, playing an important role in maintaining the life activity of human.However, there is a narrow range between its therapeutic dosage and tolerable upperintake level, easily leading to human poisoning, making selenium supplement difficult.Studies have shown nano-selenium has high bioavailability and bioactivity, lowtoxicity. It is the lowest toxicity form of selenium supplement, having goodapplication prospect. Producing nano-selenium with soft templates is the optimumselection for food and medical industries. Using oyster polysaccharide producing bywater extraction and alcohol precipitation method as template, nano-seleniumpolysaccharides was produced by reaction of sodium selenite with ascorbic acid insolution.The antioxidant capacity of nano-selenium polysaccharides were studied byusing in vitro laboratory experiments.The main contents are followed;1. Oyster polysaccharides were extracted by using methods of hot waterlixiviation and alcohol precipitation. Using extraction rate as optimizing objective,extraction temperature, extraction time, ratio of Water to raw material, ratio of ethanolto oyster and ethanol precipitation time were optimized by single factor experiments.The optimum conditions were extraction temperature60℃, extraction time3h, ratioof Water to raw material30mL/g, ratio of ethanol to oyster extract3mL:1mL, andethanol precipitation time8h.2. Using oyster polysaccharides as soft template, nano-selenium was producedby reaction of sodium selenite with ascorbic acid in solution. The content of sodiumselenite were1mM, the content of oyster polysaccharides, the ratio of ascorbic acid to sodium selenite, reaction temperature and reaction time were studied to find the effectto the reaction.The size distribution and morphology of the product were confirmedby dual-wavelength spectrophotometer, scanning electronic microscopy (SEM) andtransmission electronic microscope (TEM). The uniform stable seleniumpolysaccharides were obtained under the condition of reaction temperature40C,reaction time3h, the content of oyster polysaccharides400mg/L andN(Vc):N(Na2SeO3)=3:1.3. The antioxidant capacity of selenium polysaccharides were studied by using invitro. The results showed that nano-selenium polysaccharide is an effective hydroxylradical scavenger, and it has some capability to scavenge DPPH radical andsuperoxide radical.The IC50of nano-selenium polysaccharide scavenging activities ofDPPH、 hydroxyl radical and superoxide radical were41.94mg/L、31.8mg/L、508.1mg/L, respectively.