Synthesis and Disinfection Effect of the Pyridine-4-aldoxime Based Salts

A set of new quaternary ammonium compounds based on pyridine-4-aldoxime was synthesized, characterized with analytical data (NMR, EA, HPLC, MS) and tested for in vitro antimicrobial activity (antibacterial, antifungal) and cytotoxicity. Quaternary pyridinium-4-aldoxime salts with length of alkyl side chain from C8 to C20 and belonging to the group of cationic surfactants were investigated in this work. An HPLC experimental protocol for characterization of mixtures of all homologues has been found. Antimicrobial evaluation found that yeast-type fungi were most sensitive towards C(14) and C(16) analogues, whereas the C(16) analogue was completely ineffective against filamentous fungi. Antibacterial assessment showed versatility of C(14) and relatively high efficacy of C(16) against G+ strains and C(14) against G− strains. Notably, none of the studied compounds exceeded the efficacy and versatility of the benzalkonium C(12) analogue, and benzalkonium analogues also exhibited lower cytotoxicity in the cell viability assay.