Synthesis and Antibacterial Properties of Trimethylamine-Based Cationic Pillar[5]arene

In this study, a pillar[5]arene was synthesized based on trimethylamine, and its antibacterial activity and mechanism against Staphylococcus aureus ATCC 6538 and Escherichia coli DH5α were investigated. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined, and the influence of the pillar[5]arene on the formation of bacterial biofilms was evaluated. Transmission electron microscopy (TEM) was used to observe the damage to the bacterial cell membrane caused by trimethylamine-based pillar[5]arene, and the cytotoxicity was determined by the 3-(4,5-dimethyl-2-thiazyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) method. The results showed that the MIC and MBC were 0.125 and 1.000 mg/mL for S. aureus ATCC 6538, respectively, and 0.250 and greater than 1.000 mg/mL for E. coli DH5α, respectively. The effect of trimethylamine-based pillar[5]arene on biofilm formation was more pronounced for S. aureus ATCC 6538 than for E. coli DH5α. TEM showed that the trimethylamine-based pillar[5]arene could differently damage the cell membrane of the two strains. The MTT assay showed that the trimethylamine-based pillar[5]arene was non-toxic within the MIC range. The results of this study provide a theoretical basis for further development and utilization of the trimethylamine-based pillar[5]arene in the food field.