Synthesis and in vitro antimicrobial evaluation of new N-heterocyclic diquaternary pyridinium compounds.

Bianca Furdui,Georgiana Parfene,Gabriela Bahrim,Ioana Ghinea,Rodica Dinica,Martine Demeunynck

doi:10.3390/molecules190811572

Abstract

A series of bis-pyridinium quaternary ammonium salts (bis-PyQAs) with different aryl and heteroaryl moieties were synthesized and their antimicrobial activity investigated. The inhibition effect of the compounds was evaluated against bacteria, molds and yeasts; the activities were expressed as the minimum inhibitory concentrations (MIC). The relationships between the structure descriptors (logP, polarizability, polar surface area (2D), van der Waals area (3D)) and the biological activity of the tested bis-PyQAs are discussed.

Highlights

Quaternary ammonium salts and their variously substituted derivatives are important biological agents and have found applications in different fields [1,2,3,4]
We have previously investigated the antimicrobial properties of some diquaternary ammonium salts and found that they exerted a significant antimicrobial action against bacteria, yeasts and molds [22,24,25]
The inhibitory potential of the investigated compounds was tested against nine microorganisms, including Gram-positive bacteria (Bacillus subtilis, Bacillus cereus, Sarcina lutea), yeasts (Rhodotorula glutinis, Candida utilis, Saccharomyces cerevisiae) and molds (Aspergillus niger, Geotrichum candidum, Penicillium roqueforti)

Summary

Introduction

Quaternary ammonium salts and their variously substituted derivatives are important biological agents and have found applications in different fields [1,2,3,4]. They are used as excellent antimicrobial agents against both Gram-positive and Gram-negative bacteria [5,6,7,8,9,10]. This paper focuses on the synthesis and characterization of bis-pyridinium quaternary ammonium salts (bis-PyQAs) starting from 4,4'-bipyridine or 4-[2-(pyridin-4-yl)ethyl]pyridine, as well as the evaluation of their antimicrobial activity. The relationships between structure, molecular hydrophobicity, solubility, and the biological activity of the tested bis-PyQAs are discussed

Synthesis

Antimicrobial Activity

General

Determination of Molecular Hydrophobicity

Conclusions