Bis-Thiourea Quaternary Ammonium Salts as Potential Agents against Bacterial Strains from Food and Environmental Matrices

Abstract

In recent years, the phenomenon of antibiotic resistance in hospitals, communities and the environment has increasingly grown, so antibiotic resistance has become an urgent problem that requires a decisive and global intervention. Incorrect/unnecessary use of antibiotics contributes to increase the ability of microorganisms to develop resistance faster and faster. Research efforts must, therefore, be made to ensure a future in which antibiotic drugs will still be useful in combating infectious diseases. The search for new antibacterial compounds is fundamental. In this study, the antimicrobial activity of the compounds was evaluated against selected bacterial strains from food and environmental matrices by using the Agar Well Diffusion Assay. A total of thirty-six Gram-positive and Gram-negative bacteria were employed to determine the action spectrum and the antimicrobial effectiveness of a small series of thiourea derivatives. Results showed that the highest activities were found for compounds 1 and 4. The important role of the alkyl chain length and/or guanidine moiety in the width of action spectrum was evidenced. Further studies will allow evaluating the efficacy of the inhibiting action and the molecular mechanisms underlying this activity in order to identify compounds capable of counteracting the phenomenon of antibiotic resistance and to identify possible future applications of these newly synthesized compounds that have shown a high bactericidal action potential.

Quaternary Ammonium Salts: Insights into Synthesis and New Directions in Antibacterial Applications

“…It maintained optimal broad-spectrum antimicrobial activity when its carbon chain length was nine. 83 Weng et al synthesized a new polymerizable quaternized oligomer (PQO), used it as a dental resin material, and found that the antibacterial activity of all modified resins was significantly improved. 84 Fu et al synthesized rigid m-Ad-m containing an adamantane structure, in which GQASs with a chain length of 12 had similar antibacterial activity as BAC.…”

“…Specifically, Bonomo et al synthesized four bis-thiourea quaternary ammonium salts (BTQAS), and the thiourea derivative was active against 88.89% of the 36 test bacteria (Table ). It maintained optimal broad-spectrum antimicrobial activity when its carbon chain length was nine . Weng et al synthesized a new polymerizable quaternized oligomer (PQO), used it as a dental resin material, and found that the antibacterial activity of all modified resins was significantly improved .…”

GC Analysis, Anticancer, and Antibacterial Activities of Secondary Bioactive Compounds from Endosymbiotic Bacteria of Pomegranate Aphid and Its Predator and Protector

“…was effective against several pathogenic bacteria such as Porphyromonas gingivalis , S. aureus , S. pyrogenes and E. coli , and reported to have antifungal activity against Aspergillus niger , Candida albicans and Aspergillus clavatus [ 76 , 77 ]. 3-Methyl-4-nitro-5-(1-pyrazolyl) pyrazole, which was identified in the EA-ME of Planococcus sp., was reported in the literature to have antimicrobial activities against B. subtilis , S. aureus , P. fluorescens , P. aeruginosa and E. coli [ 78 ]. In addition, it had anticancer activities against various types of cell lines [ 79 , 80 , 81 ].…”

Novel Piperazine and Morpholine Derivatives: Mass Spectrometry Characterization and Evaluation of Their Antimicrobial Properties

“…As already known in the literature, compounds containing the morpholine ring have a wide spectrum of biological activity, including the inhibition of microbial protein synthesis [26][27][28]. The compound (4) has the morpholine ring, two heterocyclic rings, a three-membered alkyl chain (n=3) and a retro-amide (NH2CO) which enhance biological activity [29,30]. Compound (5) showed a minor but selective antimicrobial activity, despite having a five-membered alkyl chain (n=5), as the literature reports that a greater length of the alkyl chain corresponds to greater antibacterial activity.…”