Antimicrobial Activity of Amino-Derivatized Cationic Polysaccharides
To improve the antimicrobial property of chitosan, water-soluble chitosan modified in their quaternary ammonium groups were synthesized. The antimicrobial properties were evaluated against Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae and Candida tropicalis. The activities increased with increasing cationic charges and the length of the alkyl chain as follows amino-chitosan, dimethylaminoethyl-chitosan, dimethylpropyl amino-chitosan, dimethylamino-1-propyl-chitosan, diethylaminoethyl (DEAE)-chitosan, and quaternized DEAE-chitosan. The modified cationic chitosans showed high antimicrobial property against B. subtilis—Gram-positive bacteria, but were less active towards yeast (C. tropicalis and S. cerevisiae) and E. coli—Gram-negative bacteria. The simple structure of the Gram-positive bacteria may explain why the cationic chitosan derivatives are more active towards B. subtilis than yeast and E. coli. The target sites of the chitosan derivatives are assumed to be the cytoplasmic membranes of microorganisms. The antimicrobial activities were strongly dependent on the cationic charge and the molecular weight. It can be suggested that these cationic chitosan derivatives have potential as antimicrobial agents.
KeywordsAntimicrobial activity Bacillus subtilis Cationic chitosan derivatives Gram-negative bacteria Gram-positive bacteria
This research was supported by basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF-2018H1D3A2001746, 2013M3A6A8073184). This work was supported by the Energy Efficiency and Resources Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry and Energy, Republic of Korea (20153030091450). This research was supported by the KU Research Professor program of Konkuk University.
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The authors declare that they have no conflicting interests associated with this publication.
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