title: Synthesis, characterization, and antibacterial activity of N,O-quaternary ammonium chitosan.
abstract: N,N,N-Trimethyl O-(2-hydroxy-3-trimethylammonium propyl) chitosans (TMHTMAPC) with different degrees of O-substitution were synthesized by reacting O-methyl-free N,N,N-trimethyl chitosan (TMC) with 3-chloro-2-hydroxy-propyl trimethyl ammonium chloride (CHPTMAC). The products were characterized by (1)H NMR, FTIR and TGA, and investigated for antibacterial activity against Staphylococcus aureus and Escherichia coli under weakly acidic (pH 5.5) and weakly basic (pH 7.2) conditions. TMHTMAPC exhibited enhanced antibacterial activity compared with TMC, and the activity of TMHTMAPC increased with an increase in the degree of substitution. Divalent cations (Ba(2+) and Ca(2+)) strongly reduced the antibacterial activity of chitosan, O-carboxymethyl chitosan and N,N,N-trimethyl-O-carboxymethyl chitosan, but the repression on the antibacterial activity of TMC and TMHTMAPC was weaker. This indicates that the free amino group on chitosan backbone is the main functional group interacting with divalent cations. The existence of 100 mM Na(+) slightly reduced the antibacterial activity of both chitosan and its derivatives.
authors.affiliation: College of Material Science and Engineering, Huaqiao University, Xiamen 361021, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Xu
authors.forename: Meihua
authors.initials: M
authors.lastname: Xin
authors.forename: Mingchun
authors.initials: M
authors.lastname: Li
authors.forename: Huili
authors.initials: H
authors.lastname: Huang
authors.forename: Shengquan
authors.initials: S
authors.lastname: Zhou
authors.forename: Juezhao
authors.initials: J
authors.lastname: Liu
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000494:pharmacology; D048271:Chitosan / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000494:pharmacology; D055808:Drug Discovery; D004355:Drug Stability; D004926:Escherichia coli / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D000644:Quaternary Ammonium Compounds / Q000138:chemical synthesis* / Q000494:pharmacology; D017550:Spectroscopy, Fourier Transform Infrared; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D000644:Quaternary Ammonium Compounds; D048271:Chitosan