Chitooligosaccharides Class Of Schiff Base Preparation And Antioxidant Activity

Chitooligosaccharide and its derivatives were always the focus of study due to their multi-active properties such as antioxidant activity, antibacterial activity, anticancer activity, etc.The present paper studied the controllable depolymerization of chitosan by hydrogen peroxide under neutral condition using orthogonal test in detail, and thus prepared Chitooligosaccharide successfully. The number average molecular weight of Chitooligosaccharide is tested by terminal group method; the structure of Chitooligosaccharide is also affirmed by IR, UR/Vis spectroscopy.For the first time, three kinds of novel Schiff base derivatives of Chitooligosaccharide have been synthesized by Chitooligosaccharide reacted with vanillin, O-vanillin, furfural respectively. The structures of them are characterized by IR, UV/Vis spectroscopy. Furthermore, two typical transition metal complexes have been prepared by Chitooligosaccharide and its Schiff base derivatives reacted with zinc sulfate, cupric sulfate respectively. The configurations of them are also analyzed by IR, UV/Vis and AAS.The superoxide anion radical scavenging activity of Chitooligosaccharide and its derivatives and their complexes with Cu(II), Zn(II) was investigated. The NBT-illumination method was applied, where methionine and riboflavin were used as producing reagent and NBT as detecting reagent for superoxide anion radical.The experimental results indicated that all the new products including Chitooligosaccharide Schiff base metal complexes are all ableto dissolve in neutral water solution (insoluble in ordinary organic solvents).The results of antioxidant activity experiment showed that theability of scavenging radical of these series of complexes increases with increasing their mass concentration. The Cu-complexes showed a better ability of scavenging radical than that of others due to changeable valence of cupric ion.