Synthesis, Characterization and Application of Novel Cationic Surfactants as Antibacterial Agents

Abstract

It is of great necessity to develop new antimicrobial agents to overcome the accelerated increment in drug-resistant bacteria. The main aim of this work is to manufacture two cationic surfactants, QHETA-9 and QHETA-14, based on quaternary hexamethylenetetramine with long alkyl chains (C-9 and C-14) by simple one-step alkylation reaction. These surfactants were characterized by analytical and statistical data, including FTIR, 1H NMR, 13C NMR and DLS. The antibacterial activities of QHETA-9 and QHETA-14 against some pathogenic bacterial strains were tested using agar disk diffusion method. The results exhibited that QHETA-14 has higher antibacterial activity than that of QHETA-9. It displayed inhibitory zone values for Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecalis, as Gram-positive bacteria, of 22.7, 21.5 and 25.9 mm, respectively, at 200 μg/disk. Meanwhile, it recorded inhibition zone values of 17.5, 25.2 and 23.8 mm for Escherichia coli, Agrobacterium tumefaciens and Erwinia carotovora, respectively, at 200 μg/disk. As a result, the current investigation verified that the antibacterial properties of QHETA-14 were greater than those of QHETA-9 due to the increase in the length of the alkyl chain. It is clear that QHETA-14 has the potential to be used as an antibacterial agent against bacteria that cause nosocomial infections and food poisoning diseases.