| Some kinds of complexes of Chitooligosaccarides(cos) with Ln(NO3)3 and D-glucosamine with LnCl3 were prepared in this paper. We studied their antioxidant activity on hydroxyl free radical and superoxide anion free radical.Based on their excellent physical chemistry properties and pharmaceutical function, chitosan and their derivatives have been widely applied in the pharmaceutical field and biological materials. cos can be prepared by degradation of chitosan. The application of cos in pharmaceutical, food and other fields was extensively because of its good biocompatibility, degradation, non-immunogen, non-toxicity and easy-absorbability. Recently, studies have shown that cos and its derivatives have antioxidative activity both in vivo and in vitro. But further research needs to be done to better illustrate its antioxidative activity and mechanism. In addition, there is little report about the antioxidative activity of glucosamine, a degradation product of cos. The rare earth have unique physical and chemical characters. Untill now, there is no systematic report about and rare earth complexes of cos and D-glucosamine. We studied the contents as following.The coordination compounds were synthesized from Chitooligosaccarides with Ln(NO3)3, and were characterized by IR, UV-vis, Fluorescence, X-ray photoelectron spectroscopy respectively. The results show that Ln3+ion with cos formed the coordination compound, Ln3+ ion was coordinated with N atom in amino groups and O atom in secondary hydroxyl groups of cos. The coordination number of cos-Ln(III) was studied with conductivity method. The results show that in the cos-Ln(III) coordination polymer one Ln3+ was coordinated with four oxygen atoms and four nitrogen atoms, so the coordination number is 8. The scavenging effects of cos and the rare earth complexes on superoxide anion free radical were studied by NADH-PMS-NBT system. The cos and complexes all had significant scavenging effects on the superoxide anion free radical, The rare earth complexes display the higher scavenging effects on the superoxide anion free radical. The removal rate on superoxide anion free radical is increasing with the concentration of the samples. When the concentration of compound reaches to a certain value (such as more than 0.4mg·mL-1), the removal rate on the superoxide anion free radical have no significant increasing with the concentration. When the concentration is 0.4mg·mL-1, the removal rate of cos-Ln complexes on superoxide anion free radical reaches to 95%, cos is about 65%.The scavenging effects of cos and cos-Ln on hydroxyl free radical were studied by EDTANa2.Fe(Ⅱ)-H2O2 system. The cos and cos coordination compounds all had significant scavenging effects on hydroxyl free radical. The cos-Ln display the higher scavenging effects on the hydroxyl free radical. When the concentration is 2.5mg/ml, the removal rate of cos-Ln on hydroxyl free radical reaches to 82%, while the cos is about 70%. The removal rate on superoxide anion free radical is increasing with the concentration of the samples.The coordination compounds of glucosamine-Ln were synthesized from D-glucosamine hydrochloride with Ln3+ ion, and characterized by elemental analysis, molar conductivity, IR, UV-Vis and X-ray photoelectron spectroscopy respectively. The results show that Ln3+ion was coordinated with amino groups, secondary hydroxyl groups and Cl-. The elemental analysis show that one Ln3+ was coordinated with two glucosamine and two Cl-.The scavenging effects of D-glucosamine and the rare earth complexes on superoxide anion free radical were studied by NADH-PMS-NBT system. The D-glucosamine and complexes all had significant scavenging effects on the superoxide anion free radical. The removal rate of D-glucosamine and glucosamine-Ln complex on the superoxide anion free radical is increasing with their concentration. When the concentration of compound reaches to a certain value (such as more than 0.6 mmol.L-1), the removal rate on the superoxide anion free radical has no significant increasing with the concentration. At the same concentration, the rare earth complexes display the higher scavenging effects on the superoxide anion free radical.The scavenging effects of D-glucosamine and glucosamine-Ln complex on hydroxyl free radical were studied by EDTANa2-Fe(II)-H2O2 system. The D-glucosamine and glucosamine-Ln complex all have significant scavenging effects on hydroxyl free radical. The glucosamine-Ln complex displays the higher scavenging effects on the hydroxyl free radical compared with glucosamine. When the concentration is reaching to 1.0mmol.L-1, the removal rate of glucosamine-Ln complex on hydroxyl free radical is 68%, while D-glucosamine is 40%. The removal rate of D-glucosamine and glucosamine-Ln complex on hydroxyl free radical is increasing with their concentration.The study provides theoretical basis for further application of chitooligosaccharide, glucosamine and rare earth in chemistry, biological, medical and nutritional fields. |
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