| Objective The complex of nano-selenium-platycodon grandiflorum polysaccharides was prepared by the reaction of Vc reduced sodium selenite with platycodon grandiflorum polysaccharides as the template.Basis on determining the size of nano-selenium-platycodon grandiflorum polysaccharides,selenium content and acute toxicity to research its anti-oxidation activity in vitro,hypoglycemic and hepatoprotective activity in vivo.Methods To investigate the factors,such as the concentration of platycodon grandiflorum polysaccharides,the ratio of Vc and Na2SeO3,the reaction temperature and the reaction time,have effect on the formation of Nano selenium under the condition of the concentration of Na2SeO3 in the fixed reaction system by using single factor experimental method.The preparation conditions of nano-selenium were evaluated by the size and uniformity of nano-selenium,thereby the best preparation scheme has been given.The nano-selenium-platycodon grandiflorum polysaccharides complex were characterized by two-wavelength colorimetry,TEM and XRD methods.The selenium content in nano-selenium was determinated by DAN method.The scavenging rate of anion superoxide free radical,the scavenging rate of hydroxyl radical and the scavenging ability of DPPH free radical were respectively measured by pyrogallol autoxidation method,salicylic acid method and UV-visible spectrophotometry,which was compared with Vc,platycodon grandiflorum polysaccharides.56 Kunming mices were divided into two groups,the first group of 8 mices as normal group,and the second of 48 mices as model group in the study of hypoglycemic activity.The second group was disposable injected with alloxan solution to model.And choosing the mice which blood glucose value > 11.1 mmol·L-1 as successfully modeled mice.The success of model mices were divided into model group,positive group,platycodon grandiflorum polysaccharides group,nano selenium low,medium and high dose group,and each group has 8 mices.The second group was continual taken medication for 14 days and weighed quality of mices,measured blood glucose,picked the eye to take blood,and measured GSH-Px activity and MDA content in serum after the last take medication 16 h.In the experimental study of protecting the liver,56 Kunming mices were average divided into seven groups(normal,control model,positive control,platycodon grandiflorum polysaccharides group,Nano-Selenium low,medium and high dose group).After a week of normal feeding,continuous intragastric take medicine 14 days.All mices were injected with CCl4 olive oil solution except normal group after take medicine1 hour on the 7th days and 14 th days,then obtained blood from eyeball and examined ALT,AST,ALP,ALB,GLB and TP levels in serum and GSH,MDA levels in liver tissues after the late of medication 16 hours,and observed histomorphology of the same part of the liver.Results The optimum process of preparation of nano selenium-platycodon grandiflorum polysaccharides complex with the evenly particles as follows: the final concentration of polysaccharides was 100 mg·L-1,the molar ratio of Vc and sodium selenite was 3:1,the reaction time was 4 h,and the reaction temperature was 40 ?.The products were crystalline powder which the particle size was about 50 nm,and the solution is still orange after one month at room temperature without precipitation.The content of selenium is 4.018 %,the LD50 of acute toxicity test were not measured.The anti-oxidation results showed that the IC50 of the nano selenium-Platycodon grandiflorum polysaccharides,platycodon grandiflorum polysaccharides on scavenging superoxide anion radicals were 1.72 mg·mL-1 and 54.44 mg·mL-1,respectively.The IC50 of scavenging hydroxyl radicals were 3.19 mg·mL-1 and 8.27 mg·mL-1,respectively.The IC50 of scavenging DPPH free radicals were 6.76 mg·mL-1 and 26.51 mg·mL-1,respectively.The reducibility of nano selenium was better than Platycodon grandiflorum polysaccharides.The result of hypoglycemic activity expressed that the level of blood sugar(p < 0.01)and the content of MDA(p < 0.01)in serum in the high and middle dose group in serum were lower than blood sugar in model group,and the activity of GSH-Px(p < 0.01)was significantly improve than model group.However,these indexes were not significantly different from the control group and these indexes of platycodon grandiflorum polysaccharides group were not significantly improved.The result of liver activity test indicated that the activities of ALT,ALP,GLB and AST(p < 0.01)in serum and MDA,GSH(P < 0.01)in liver tissue were significantly reduced,TP?ALB(p < 0.01)in liver tissue were significantly improved compared with model group,and there was no difference with the control group.The low dose of nano-selenium could significantly improve these indexes.These indexes of platycodon grandiflorum polysaccharides group did not significantly improved.But the middle and high dose groups can significantly improve the histopathological lesion which caused by CCl4,and the therapeutic activities were significantly better than low dose group and platycodon grandiflorum polysaccharides treatment groups.Conclusions The method of prepared nano-selenium had mild reaction condition and was easily controlled,and the size of nano-selenium particles is suitable,uniform and stable.It has a strong ability to remove superoxide anion radicals,hydroxyl radicals and DPPH free radicals,moreover it also has very effective therapeutic capacity in diabetes and drug-induced liver injury.This research provides foundation for developing hypoglycemic,liver and antiaging drugs,and to provide a large number of theoretical bases. |
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