Synthesis and antibacterial activity of new dimeric pyridinium chlorides based on 2,2-bis(hydroxymethyl)propane-1,3-diyl spacer

Quaternary Ammonium Compounds (QACs) and Ionic Liquids (ILs) as Biocides: From Simple Antiseptics to Tunable Antimicrobials

Quaternary ammonium compounds (QACs) belong to a well-known class of cationic biocides with a broad spectrum of antimicrobial activity. They are used as essential components in surfactants, personal hygiene products, cosmetics, softeners, dyes, biological dyes, antiseptics, and disinfectants. Simple but varied in their structure, QACs are divided into several subclasses: Mono-, bis-, multi-, and poly-derivatives. Since the beginning of the 20th century, a significant amount of work has been dedicated to the advancement of this class of biocides. Thus, more than 700 articles on QACs were published only in 2020, according to the modern literature. The structural variability and diverse biological activity of ionic liquids (ILs) make them highly prospective for developing new types of biocides. QACs and ILs bear a common key element in the molecular structure-quaternary positively charged nitrogen atoms within a cyclic or acyclic structural framework. The state-of-the-art research level and paramount demand in modern society recall the rapid development of a new generation of tunable antimicrobials. This review focuses on the main QACs exhibiting antimicrobial and antifungal properties, commercial products based on QACs, and the latest discoveries in QACs and ILs connected with biocide development.

Investigations into the structure-activity relationship in gemini QACs based on biphenyl and oxydiphenyl linker

Eighteen novel gemini quaternary ammonium compounds were synthesized to examine the effect of linker nature, aliphatic chain length and their relative position on antibacterial and antifungal activity. The synthesized compounds showed strong bacteriostatic activity against a panel of both Gram-positive and Gram-negative bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and two fungi. Some of these compounds exhibited a wider and more potent antimicrobial spectrum than commonly-used antiseptics, such as benzalkonium chloride (BAC), cetylpyridinium chloride (CPC), chlorhexidine digluconate (CHG) and octenidine dihydrochloride (OCT).

Iso-octenidine: Promising Octenidine Analogue with Improved Solubility

Iso-octenidine, an isomer of octenidine dihydrochloride, was synthesized and studied for the first time. Iso-octenidine was demonstrated to be 3-fold more soluble in water in comparison to original octenidine, and both substances had remarkably similar antibacterial activity (tested on Escherichia Coli and Micrococcus luteus).