Structure‐Activity Relationships for Poly(phenylene)vinylene Derivatives as Antibacterial Agents

Abstract

A series of poly(phenylene)vinylene (PPV) derivatives with different geometries and peripheral functional groups have been synthesized by Horner‐Wadsworth‐Emmons reaction. Compounds bearing carboxylic acid or quaternary ammonium functional groups prepared by this metal‐free protocol were weakly active against both Gram‐negative and Gram‐positive bacteria, which is in contrast to previously reported results. The activity of polyanionic derivatives was higher for Gram‐negative bacteria and showed bacteriostatic behavior, whereas polycationic derivatives were clearly more active against Gram‐positive bacteria and behaved as bactericidal agents. The spatial disposition of the active groups seems to play a key role, with the highest activity observed for a C3v geometry. The presence of quaternary ammonium functional groups also facilitated the internalization of the molecules into the bacteria. Levels of cytotoxicity similar to that of the solvent were obtained for most compounds against COS‐1 and VERO cells.

Synergic activity of oligostyrylbenzenes with amphotericin B against Candida tropicalis biofilms

“…ones (Tolosa et al, 2018). In addition, the antifungal activity on planktonic and sessile forms of C. tropicalis was evaluated.…”

“…The preparation of the OSBs was carried out using a methodology described previously based on the reaction of Horner-Wadsworth-Emmons (Tolosa et al, 2018). From a structural point of view, compound OSB 1 is characterized as an anionic molecule at the pH value where the biological experiments described below are performed, whereas OSB 2 and 3 have a cationic character (inset Figure 1).…”

“…An important goal of current antifungal pharmaceutical research is to find new compounds with antifungal activity but with fewer adverse effects in patients, which can be used alone or in combination with other antifungal agents to reduce drug concentrations in order to minimize the incidence of side effects. Oligostyrylbenzene (OSB) compounds are a family of molecules that have previously shown antimicrobial activity (Boulos et al, 2013;Iscla et al, 2015;Moral et al, 2019;Tolosa et al, 2018). These compounds, with a π-conjugated structure, have been studied due to their excellent optical properties and have shown a good quantum fluorescence performance in solution, in solid-state, or as charge-transfer systems.…”

“…In this way, it has been shown that tris(styryl)benzenes have better antibiotic activity than the corresponding tetrastyrylbenzenes, indicating that the number of functional groups does not always result in higher activity, as a perfect balance between the hydrophobic and hydrophilic parts of the molecule is required. The cationic OSBs result in bactericidal action that penetrates the bacterial cell wall, with the anionic OSBs remaining outside and attached to the membrane and thereby developing a bacteriostatic behavior (Tolosa et al, 2018).…”

Antimicrobial anilinium polymers: The properties of poly(N,N‐dimethylaminophenylene methacrylamide) in solution and as coatings

“…Ortega et al prepared and studied anilinium‐terminated carbosilane dendrimers and showed that they were effective against Staphylococcus aureus and Escherichia coli . Very recently, Tolosa et al examined the biocidal activity of poly(phenylene)vinylene derivatives with different geometries and peripheral functional groups, including the aniline derivatives. These latter compounds only exhibit moderate activity; however, these two reports demonstrate the importance of multivalence and provide sufficient motivation for further exploration of the biocidal behavior of anilinium‐containing macromolecules.…”