Chitosan Sulfate Synthesis And The Inhibitory Effect Of Crop Pathogens

The sulfation of chitin/chitosan is the most interesting field of itschemical modification. This experiment is carried out to investigate and fixthe optimum reactive condition of sulfated chitosan. Sulfated chitosan ischaracterized by elemotal analysis, IR and NMR spectra. From its anti-crop-pathogen activities, we study its anti-crop-pathogen mechanism andreach a qualitative conclusion. The main.results are as follows:1.The method of H₂O₂ degration does not influence the degree of de-acetylation of chitosan,the molecular weight of degraded chitosan isbetween 10,000 and 50,000.2.N-carboxymethlation of chitosan is a quantitative reaction between thefree amino groups of chitosan and glyoxylic acid, the yield ofN-carboxymethylation of chitosan is 100%.3.The optimum time of sulfated reaction of chitosan is about 9 hours;thissulfated product has the highest S-content.The lower the molecularweights of chitosan or N-carboxymethylation of chitosan is,the easier thesulfated reaction is. In this experiment, the sulfated chitosan is N-sulfatedchitosan and N-carboxymethyl-sulfated chitosan is N-carboxymethyl-3,6-O-sulfated chitosan.4.Chitosan and its derivatives have antibacterial activities in vitro. However,the antibacterial activities of sulfated chitosan and N-carboxy-methyl-sulfated chitosan are weaker than thOse of chitOsan andN -cathexymethyl-chitosan. ms shows that s ul fat ion o f chito san cannotimprove itS anibacterial activity substantially.5. ChitOsan and its derivatives have not antifungi activities in viIrO, bUt theyhave anifungi activities in vivo. This shows the mechasm of antifungiactivities ofchitOsan and its derivatives is an inducing ation.