Influence of Parabens on Bacteria and Fungi Cellular Membranes: Studies in Model Two-Dimensional Lipid Systems
Michał Flasiński1, Sara Kowal1, Marcin Broniatowski1
1Department of Environmental Chemistry, Faculty of Chemistry and ‡Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University , Gronostajowa 2, 30-387 Kraków, Poland.
Abstract:
Langmuir monolayers were used to study the influence of four commercially applied parabens on multicomponent systems composed of lipid species characteristic of the cellular membrane of microorganisms found in carbohydrates and proteins reaching products, including food and cosmetics. The aim of the undertaken studies was to shed new light on the problem of parabens' interactions with membrane lipids and their affinity for monolayers differing with regard to the composition, mutual lipid ratios, and physicochemical properties. The discussion is based on the π-A isotherm characteristics, surface morphology observation performed with BAM, and analysis of the diffraction data collected for the periodically ordered lipid domains present in the investigated multicomponent films. Our studies revealed that the selected parabens are capable of surface film modification and that the magnitude of this effect increases with the number of methylene groups in the ester part of paraben molecules. We found that the strongest destructive effect was observed for model 1 (Staphylococcus aureus), a lower effect was observed for model 2 (Pseudomonas aeruginosa), and the lowest effect was observed for model 3 (Candida albicans). It was inferred that such a trend appears due to the composition of the artificial membranes, i.e., above all, in the presence or lack of sterol molecules and the content of negatively charged lipids.
Insights
Parabens, used in cosmetics and food, alter microbial cell membranes. Their disruptive effect on lipid monolayers increases with molecular size, varying by microorganism type due to membrane composition differences.
Area of Science:
- Biochemistry
- Microbiology
- Surface Chemistry
Background:
- Parabens are widely used preservatives in food and cosmetics.
- Microbial cell membranes are crucial for organism survival and integrity.
- Understanding paraben-lipid interactions is vital for assessing their safety and efficacy.
Purpose of the Study:
- To investigate the impact of four commercial parabens on model microbial cell membranes.
- To analyze how paraben structure and membrane composition influence their interaction.
- To elucidate the mechanism of paraben interaction with lipid monolayers.
Main Methods:
- Langmuir monolayers were employed to model microbial cell membranes.
- Surface pressure-area (π-A) isotherms characterized paraben interactions.
- Brewster Angle Microscopy (BAM) assessed surface morphology.
- Diffraction analysis examined lipid domain structures.
Main Results:
- Parabens modified the surface films of lipid monolayers.
- The disruptive effect of parabens intensified with increased methylene groups in their ester chain.
- Strongest effects were observed on membranes mimicking Staphylococcus aureus, followed by Pseudomonas aeruginosa, and then Candida albicans.
- Membrane composition, particularly sterol and charged lipid content, influenced paraben efficacy.
Conclusions:
- Parabens interact with and modify microbial membrane lipid structures.
- The extent of paraben's membrane disruption is dependent on both paraben molecular structure and the specific lipid composition of the target membrane.
- Sterol presence and charged lipid content are key factors determining paraben's impact on membrane integrity.
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