Title : Membrane activity of honokiol, an antimicrobial agent for enhanced safety and sustainability – studies in model systems
Abstract:
Antimicrobial resistance has developed as one of the major urgent threats to public health. Due to clinical and epidemiologic significance of this issue, there is an increasing demand to search for innovative and safe antimicrobial substances for healthcare, agriculture, food and cosmetics production. A very promising approach in this matter is the use of substances of natural origin, that exhibit wide range of biological properties. Honokiol, a polyphenolic compound, present in bark extract of Magnolia officinalis, shows the potential to work as an antibacterial, anti-inflammatory, anticancer, antioxidant and neurotherapeutic agent. However, despite many studies on the effect of this substance on bacterial cells, its molecular mechanism of action still requires verification. It is assumed that the first site of honokiol action against bacterial cells is cell membrane and the structure of membrane lipids may have the significant influence on honokiol antibacterial activity. Therefore, the aim of the presented research was to analyze the effect of honokiol on the properties of model bacterial cell membranes, considering differences in lipids structure. The investigations were performed for membrane-mimicking systems formed from individual lipids characteristic for bacterial membranes (phosphatidylethanolamines, phosphatidylglycerols and cardiolipins) and from multicomponent mixtures of this lipids (imitating Escherichia coli and Staphylococcus aureus membranes). The results of this experiments allowed to analyse the effect of the lipid structure, i.e. polar headgroup (POPE vs POPG comparison) and hydrophobic chain (TOCL vs TSCL comparison) on the interactions with honokiol. As model membranes Langmuir monolayers and liposomes were be applied. Based on experiments conducted using various techniques (Brewster angle microscopy, dynamic light scattering, fluorescence anisotropy) the influence of honokiol on intermolecular interactions, stability, organization and morphology of artificial cell membranes in the context of its membrane-related antibacterial properties were assessed.
