The antibacterial structure-activity relationship for common chitosan derivatives

• Published in: International journal of biological macromolecules Vol. 165; no. Pt B; pp. 1686 - 1693
• Main Authors: Rathinam, Sankar, Solodova, Svetlana, Kristjánsdóttir, Ingibjörg, Hjálmarsdóttir, Martha Á., Másson, Már
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.12.2020
• Subjects: Anti-Bacterial Agents - chemical synthesis; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Antimicrobial; Chitosan; Chitosan - chemical synthesis; Chitosan - chemistry; Chitosan - pharmacology; Degree of substitution; Escherichia coli; Escherichia coli - drug effects; Microbial Sensitivity Tests; Proton Magnetic Resonance Spectroscopy; Staphylococcus aureus; Staphylococcus aureus - drug effects; Structure-Activity Relationship; Antimicrobial; Chitosan; Degree of substitution; Escherichia coli; Staphylococcus aureus
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2020.09.200

The relationship between the degree of substitution and antibacterial activity was studied for six common chitosan derivatives N, N,N-trimethyl chitosan (TMCNH2/TM and TMCTM/DM) N-(2-(N,N,N-trimethylammoniumyl)acetyl)-chitin (TACin), N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan (HTC), hydroxypropyl chitosan (HPC), thioglycolic chitosan (TGC) and carboxymethyl chitosan (CMC). The degree of substitution (DS) in the 36 studied samples ranged from 0.02 to 1.1 as determined by 1H NMR. The activity was determined as the minimum inhibitory concentration (MIC) against S. aureus and E. coli at pH 7.2 and 5.5. The antibacterial effect of TMC and TACin increased with DS. Samples of these derivatives with high DS were more active than chitosan at pH 7.2. HTC was more active than chitosan against S. aureus, but this activity was not affected by DS. In other cases, the activity of HTC decreased with an increase in DS. The DS for the TGC was very low and the activity was similar to unmodified chitosan. The activity of HPC decreased with DS. CMC was not active in this study. [Display omitted] •Nineteen samples of chitosan derivatives HTC, TGC, HPC, and CMC were synthesized with DS ranging from 0.02 to 1.1•The study included seventeen previously synthesized samples of TMC and TACin derivatives•The relationship between DS and activity against S. aureus and E. coli was studied•The activity of TMC and TACin increased with DS at pH 7.2•The activity of HPC decreased with increasing DS and CMC was not active