The antibacterial structure-activity relationship for common chitosan derivatives

Sankar Rathinam, Svetlana Solodova, Ingibjörg Kristjánsdóttir, Martha Hjálmarsdóttir, Már Másson*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


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.

Original languageEnglish
Pages (from-to)1686-1693
Number of pages8
JournalInternational Journal of Biological Macromolecules
Publication statusPublished - 15 Dec 2020

Bibliographical note

The research work was funded by the Icelandic Research Fund (Rannis Grant No. 1709-0210) and by a doctoral grant from the University of Iceland Research Fund. We thank Primex ehf for donating the chitosan starting material.

Publisher Copyright:
© 2020 Elsevier B.V.

Other keywords

  • Antimicrobial
  • Chitosan
  • Degree of substitution
  • Escherichia coli
  • Staphylococcus aureus


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