Preparation, characterization and antibacterial activity of a novel soluble polymer derived from xanthone and O-carboxymethyl-N, N, N-trimethyl chitosan

In this contribution, a novel soluble and antibacterial polymer, O-xanthonyl-chitosan (CTMC-Xan), was synthesized successfully by grafting 1,3-dihydroxy-xanthone (Xan) to the side chains of O -carboxymethyl- N , N , N -trimethyl chitosan (CTMC). The chemical structure and physical properties of the polymer were analyzed by 1 H NMR, FT-IR spectra, UV spectra and XRD. The results showed that Xan could covalently bond with the carboxyl groups of CTMC by esterification at a grafting ratio of 9.1%. XRD patterns indicated that CTMC-Xan does not exhibit crystallization. The solubility tests showed that CTMC-Xan was completely dissolved and stable in neutral solution but unstable in acid or basic conditions. Moreover, it was found that the antibacterial activity against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) of CTMC-Xan was much stronger than that of Xan and CTMC, and the minimal bactericidal concentration (MBC) was 125 μg·mL −1 . Due to the enhanced solubility and antibacterial activity, CTMC-Xan could potentially serve as a desirable biomaterial for food and pharmaceutical applications .