Preparation And Efficacy Of Selenized Rice Germ Polysaccharides

The polysaccharide and selenium combine to form organic compound selenium polysaccharide,which has the dual function of organic selenium element and polysaccharide,enhances the solubility,absorption and utilization of selenated polysaccharide,and is safer than inorganic selenium compound.The selenized rice embryo polysaccharides were prepared by nitric acid method and acetic acid method.The structure of selenized rice blast polysaccharides was characterized by ultraviolet and infrared spectroscopy,and the anti-oxidation experiments of the selenized rice germ polysaccharides in vitro and in vivo were conducted to determine the distribution and toxicity of selenium.It was proved that the selenized rice embryo polysaccharide has stronger oxidation resistance and safety.The main findings are as follows:（1）Rice embryo polysaccharide extraction,separation and component analysis.Ultrasonic assisted extraction of rice embryo polysaccharides,rice embryo polysaccharide extraction rate of 16.24%,total carbohydrate content of rice embryo polysaccharide was91.42%.After the pre-column derivatization of rice germ polysaccharides,the monosaccharide components in the polysaccharides were mannose,rhamnose,glucuronic acid,galacturonic acid,and glucose,and the molar ratios of monosaccharides were 1.00:5.13:2.24:1.69:39.22,where glucose accounts for 79.58%of monosaccharides in polysaccharides.Analysis by amino acid automatic analyzer,the total amino acid content in the rice embryo polysaccharide sample was 2.01%.（2）Preparation and structure characterization of selenized rice embryo polysaccharide.Preparation of selenized rice blastospore polysaccharide（Se-REP1）by acetic acid method:mass ratio of polysaccharide to sodium selenite（1.000:0.500）,glacial acetic acid 1m L,temperature 50℃,time 42h,repeated 3 times,using subtraction method The selenium content in selenized rice embryo polysaccharide（Se-REP1）was determined to be 145.42±2.75mg/kg.Preparation process of selenized rice embryo polysaccharide（Se-REP2）by nitric acid method:The preparation process of selenized rice embryo polysaccharide was optimized by L₉（3⁴）orthogonal design,and the suitable preparation process was determined as temperature70℃,time 5h,and nitric acid concentration.The mass ratio of 0.5%polysaccharide to sodium selenite was（1.000:0.750）.The experiment was repeated 3 times.The selenium-containing rice sebaceous polysaccharide（Se-REP2）had an organic selenium content of 179.73±2.25mg/kg by subtraction.The structure of selenized rice embryo polysaccharides was analyzed by UV and IR spectra.The results showed that the rice embryo polysaccharide has been successfully selenized,and selenized polysaccharides exist as selenate esters.The solubilities of REP,Se-REP1,and Se-REP2 were 80.19%,84.34%,and 84.57%,respectively,and the color changed to pink.The solubility of rice embryo polysaccharide increased after selenization.（3）Antioxidant properties of selenized rice embryo polysaccharides.Antioxidant activity in vitro was compared using O^2-,OH,DPPH free radical scavenging assays and reducing power compared with rice embryo polysaccharide（REP）,selenized rice embryo polysaccharide（Se-REP1）prepared by the acetic acid method,and selenium rice prepared by the nitric acid method.Germ polysaccharide（Se-REP2）antioxidant activity.The results showed that the five different concentrations of REP,Se-REP1,and Se-REP2 had different degrees of scavenging capacity for O^2-,OH^-,and DPPH radicals,and their reducing power increased with increasing concentrations,but they were all lower than Vc.The oxidation resistance is weak.Antioxidant activity in vivo The SOD,MDA,GSH-Px,and T-AOC in serum,liver,kidney,and heart tissue of mice were measured by measuring the antioxidant capacity of REP,Se-REP1,and Se-REP2 in vivo.The results showed that Se-REP1 and Se-REP2 could increase the activity of SOD,GSH-Px and T-AOC in tissues and serum to some extent,and reduce the content of MDA.The effect was stronger than REP.However,the activity of T-AOC in the heart was not significant,and the activity of SOD enzyme in the kidney was not significant.The effect of reducing MDA content in the liver and kidney was not significant.The results showed that the antioxidant activity of selenized rice embryo polysaccharide was stronger than that of rice embryo polysaccharide.Secondly,Se-REP2 had stronger antioxidant activity than Se-REP1,and all had higher antioxidant activity than Vc.（4）Acute toxicity test of selenized rice embryo polysaccharide.The modified Koushi method was used for the experiment.The LD₅₀of sodium selenite was 23.16 mg/kg,and the95%confidence range was 18.69 to 28.68 mg/kg.According to the maximum tolerated dose（MTD）method,the MTD of selenized rice embryo polysaccharide on male and female mice was greater than 20000 mg/kg.bw.This shows that the selenized rice embryo polysaccharide is far less toxic than sodium selenite.After the median lethal dose was measured,mice were fed for 30 days.In the high-dose group,sodium selenite was compared with the control group,and mice were piled up and inactive.The three doses of sodium selenite and selenized rice blastose polysaccharide in the low-and middle-dose groups had normal behavior relative to the control group,with no significant difference.The body weights of mice with different doses of sodium selenite and selenium myo-lipid polysaccharide and the control group gradually increased,and there was no significant difference in weight gain（P>0.05）.There was no significant difference in selenium content in blood,heart,liver,kidney,spleen,lung,muscle,and bone in mice with different doses of sodium selenite,indicating that inorganic selenium is not easily absorbed by the body.Although selenium content in mouse heart,kidney and muscle increased in different dosage groups,there was no significant difference in selenium content,but selenium-rich rice embryo polysaccharides in middle dose group were found in the liver and spleen of mice.The content of Pb was extremely significant（P<0.01）.Selenium content in the high-dose group had a significant difference in the selenium content in the blood and lungs（P<0.05）.The content of selenium in the spleen,liver,and bone was extremely high.The significant difference（P<0.01）indicates that the selenized rice embryo polysaccharide is mainly distributed in the spleen,liver and bone after being absorbed in mice.Compared with the control group,the high-dose sodium selenite group had a significant difference in the heart-body ratio（P<0.01）and a significant decrease in the kidney-to-body ratio（P<0.05）.The ratios of the remaining organs in the selenite group also decreased.Rat organs may undergo degeneration and atrophy.There was no significant difference between the selenized rice embryo polysaccharide group and the control group.There was no significant difference in the selenized rice blastulase polysaccharide group between the three dose groups,indicating that the selenized rice blast polysaccharide has no obvious lesions on the mouse organs.