Synthesis And Antidiabetic Activities Of Selenium Nanoparticles In The Presence Of Chitosan And Polysaccharides From Catathelasma Ventricosum

Selenium is an essential trace element for human body.However,because of the narrow range between the thresholds of functionality and toxicity,the bioavailability and biological activities of selenium are extremely restrained.The latest studies have shown that selenium nanoparticles?SeNPs?have higher safety and biological activity than traditional selenium preparations,having good application prospect.In this study,using chitosan?CTS?,polysaccharides from Catathelasma ventricosum?CVPs?as dispersant,two polysaccharides-SeNPs complexes,that is,CTS-SeNPs and CVPs-SeNPs were prepared by reduction method apparently.Besides,taking the particle size as the index value,the optimal preparation conditions of CTS-SeNPs and CVPs-SeNPs were obtained by single factor and orthogonal experiment.The stability and surface morphology of these two composites prepared under the optimum conditions were determined as well.Finally,the antidiabetic activities of CTS-SeNPs and CVPs-SeNPs were investigated.The main contents and results as follow:1.CTS-SeNPs was prepared by the reaction of sodium selenite with ascorbic acid using CTS as dispersant.The effects of some preparation conditions,such as reaction temperature,reaction time,concentrations of ascorbic acid and CTS on the particle size of CTS-SeNPs were studied.The surface morphology of the CTS-SeNPs prepared under the optimum conditions was observed by transmission electron microscope?TEM?and scanning electron microscope?SEM?.The particle size of the CTS-SeNPs was measured after being placed at 25^?C and 4^?C for different time,and its stability was determined according to the change of particle size with time.Furthermore,using streptozotocin?STZ?-induced diabetic mice as a model,the in vivo antidiabetic activity of CTS-SeNPs was studied.The results showed that spherical CTS-SeNPs with a particle size of about 54nm could be obtained when the concentration of ascorbic acid was 0.04 mol/L,the concentration of ascorbic acid was 1.0 mg/mL,the reaction temperature was 25^?C and the time was 2 h.It could be stable for approximately 60 days at 4^?C.Additionally,the results indicated that CTS-SeNPs at a dose of 2.0 mg Se/kg·bw exhibited higher antidiabetic activities than SeNPs and Na₂SeO₃ with the same selenium content.2.CVPs-SeNPs was prepared by the reaction of sodium selenite with ascorbic acid using CVPs as dispersant.The effects of some preparation conditions,such as reaction time,ultrasonic time,concentration of ascorbic acid,pH on the particle size of CVPs-SeNPs were studied.The surface morphology of the composite prepared under the optimum conditions was observed by transmission electron microscope?TEM?.The stabilities of the composite in different temperature were determined according to the variation of the particle size with time,and note that the particle size of CVPs-SeNPs was measured by nano particle sizer.Further,using glibenclamide,metformin hydrochloride,V_E,organic selenium?selenocysteine?and inorganic selenium?sodium selenite?as controls,the in vivo antidiabetic activity of CVPs-SeNPs was studied.The results showed that,optimum preparation conditions of CVPs-SeNPs were:ultrasonic time 60 min,concentration of Vc0.04 mol/L,reaction time 2 h,pH 7.0,and the mean diameter of the CVPs-SeNPs synthesized under these conditions was around 49.73 nm.The CVPs-SeNPs in TEM was spherical and uniformly dispersed.CVPs-SeNPs?particle size of about 50 nm?could be stable for approximately 3 months at 4^?C,1 month at 25^?C.In addition,CVPs-SeNPs showed significantly higher antidiabetic activities?p<0.05?than other selenium preparations such as SeNPs,selenocysteine,sodium selenite.