Antibacterial and antibiofilm effects of natural phenolic acids: Insights into structure-function relationships, extracellular pH, and morphological changes.

Wound infections are a challenging healthcare burden against which treatment is hindered by the presence of biofilms and the rise in antibacterial resistance. To date, the potential of natural phenolic acids as topical antibacterial agents is under-researched. The aim of this study was to investigate and compare the antibacterial and antibiofilm effects of 5 hydroxycinnamic acids (caffeic acid, chlorogenic acid, IMPORTANCE: The search for new antibacterial agents is one of the highest healthcare priorities. Phenolic acids are increasingly researched alone and as part of various drug delivery systems for wound care applications. However, to date, the available literature on the antibacterial effects of these compounds is rather fragmented and outdated, with unreproducible results. In this study, we link the physicochemical properties and structure of the molecules with their antibacterial and antibiofilm potential, investigate phenolic acid's impact on the bacterial metabolism-induced extracellular pH change, and use SEM imaging to characterize the morphological changes of both planktonic bacteria and biofilms in response to phenolic acid treatment. Additionally, we provide an assessment of the compound ADMET properties with respect to their potential topical application. The data can be used in the future to test potential synergic effects with antibiotics, develop drug delivery systems, and investigate the efficacy of these agents against multi-resistant bacterial strains.