Biologically Active Polymers:Modification and Anti-microbial Activity of Chitosan Derivatives

摘要

The principal derivative of chitin is chitosan,which is obtained by deacetylation of chitin.Chemical modification of synthetic and natural polymers is a convenient way to obtain materials with unique chemical and physical properties.Chitosan has an amino group at C-2 which is important because amino groups are nucleophilic and readily react with electrophilic reagents.Chitosan modified under mild conditions often results in regioselec-tivity for the C-2 amino group.In the present work,this reactivity was exploited to attach biologically active moieties into the amino groups of chitosan to yield anti-microbial chi-tosans.Specifically,vanillin,p-hydroxybenzaldehyde,p-chlorobenzaldehyde,anisaldehyde,methyl 4-hydroxybenzoate,methyl 2,4-dihydroxybenzoate,propyl 3,4,5-trihydroxybenzoate and 2-hydroxymethylbenzoate were attached.The anti-microbial activity of these modified chitosans was explored against fungi such as Candida albicans SC5314,Aspergillus flavus and Fusarium oxys-porium.Also,they were tested against bacteria such as Bacillus subtilis,Escherichia coli and Staphylococcus aureus.These modified chitosans were found to be highly active toward fungi species more than bacterial species.