Studies Of Synthesis And Bioactivities Of Inulin Derivatives

As a kind of natural plant polysaccharides,inulin has good physical and chemical properties as well as physiological functions,inulin is a kind of renewable biological resources which is cheap and biocompatible.At present,inulin has been widely used in food,feed,health products,chemical industry,bio-energy and pharmaceuticals industry and so on.To exploit the potential value of inulin is of great significance.The exploitation of inulin starts late in our country.Although the inulin has been widely uesd in food processing industry,but in some areas,it is still at the initial stage and has great room for developmen.In this text,we studied with natural inulin as raw materials,referenced the research hotspot at home and abroad,and we combined the research with our professional knowledge.According to some targeted chemical modification,we designed and synthesized a series of inulin derivatives with the corresponding biological activities.This text can be used as a reference of inulin exploitation.In this study,three kinds of inulin derivatives taking chloracetyl inulin as reaction intermediate were synthesized,which were inulin derivatives containing quaternary ammonium salt,inulin derivatives containing quaternary phosphonium salt,and inulin derivatives containing halogenobenzene.The synthetic method was easy,efficient,and the reaction conditions was mild,the product is single and easily to be separated.Then their strucuture were confirmed by FT/IR and NMR.Later on,we researched the antioxidant ability of the quaternary ammonium salt inulin derivatives,and the antifungal activities of the quaternary phosphonium salt inulin derivatives as well as the halogenobenzene inulin derivatives.In order to study the antioxidant activity of inulin derivatives containing quaternary ammonium salt,hydroxyl radical scavenging ability,DPPH radical scavenging ability and superoxide anion radical were taken into experiment.The results indicated that all the modified inulin derivatives with quaternary ammonium salt can obviously increase the antioxidant activity of inulin.2-imidazole-acetyl inulin chloride(IAIL)exhibited the greatest radical scavenging ability towards hydroxyl radical and superoxide anion radical,at the concentration of 0.4 mg/mL,its hydroxyl radical scavenging rate could reach 84.6%,and its superoxide anion radical scavenging rate could reach 67.8% at the concentration of 1.6 mg/m L,the value is much higher than inulin itself.2-(N,N-dimethyldecylamine)-acetyl inulin chloride(DMDAAIL)showed the greastest DPPH radical scavenging ability,at the concentration of 1.6 mg/mL,its DPPH radical scavenging rate could reach 80.7%.With the help of mycelium growth rate method,we measured the antifungal ability of inulin derivatives with quaternary phosphonium salt and halogenobenzene.Three kinds of agricultural common pathogenic fungi(colletotrichum lagenarium,Fusarium oxysporium,and Phomopsis asparagi)were chosen as the test strains.The antifungal ability of inulin and its derivatives were compared and the results showed that inulin had no effect on antifungal activity,but all the tested inulin derivatives owned a good inhibitory ability of fungi.Among them,the antifungal rate of inulin derivatives with quaternary phosphonium salt was more significant.As for the inulin derivatives with quaternary phosphonium salt,the longer alkyl chain of quaternary phosphine salt,the higher inhibitory rate of fungi.The chain length of C-6-(2-tricyclohexylphosphine)-acetyl inulin chloride(TCHPAIL)and C-6-(2-triphenylphosphine)-acetyl inulin chloride(TPhPAIL)was no different,but the antifungal ability of TPhPAIL was better than the front one.It would be reasonable to presume that phenyl in quaternary phosphonium salt contributes more to the antifungal activity than alkyl since phenyl has better electron withdrawing ability.As for inulin derivatives with halogenobenzene,the kind of halogen and the replaced position at benzene had an effect on the its antofungal ability since chlorine was more effective than fluorine and replacement taken on para-position was better than ortho-position.