Effect of chlorogenic acid on the phase transition in phospholipid and phospholipid/cholesterol membranes

Abstract

Chlorogenic acid (CGA) is present in many plants, especially in green coffee, dry plums, and bilberries. It is an important bioactive polyphenol. Studies showed that CGA has an antioxidative, bacteriostatic, anticancer, antiviral, and anti-inflammatory activity. Despite great interest in this compound, its interaction with the lipid model membrane has not yet been investigated. To better understand the relationship between the biological activity of CGA and its interaction with biological membranes, the thermotropic behavior of model lipid membranes was investigated. The effect of CGA on the model lipid membrane, specifically on the lipid bilayer phase transitions, was examined by the combined methods: differential scanning calorimetry and fluorescence spectroscopy. In particular, the degree of packing order of the hydrophilic phase of the lipid bilayer was determined using the fluorimetric method with Laurdan and Prodan probes, while the fluorescence anisotropy of the hydrophobic phase with the DPH and TMA-DPH probes. The results of the study show that CGA incorporates mainly into the hydrophilic part of membrane, changing the packing order of the polar heads of lipids. No significant changes were recorded in membrane fluidity of the hydrophobic membrane region, for the fluorescence anisotropy practically did not change. One can thus infer that CGA does not penetrate deep into the hydrophobic area of the membrane.

Formulation of Nano/Micro-Carriers Loaded with an Enriched Extract of Coffee Silverskin: Physicochemical Properties, In Vitro Release Mechanism and In Silico Molecular Modeling

“…It was shown that the phytoconstituents were positioned within the lipid bilayer, exhibiting high hydrogen binding between the polar site of the lipid bilayer and the hydroxyl groups of 5-caffeoylquinic acid. Pruchnik et al [65] also confirmed the interaction between chlorogenic acid and biological membranes, as verified in this work. The referenced authors evaluated the chlorogenic acid permeation mechanism by differential scanning calorimetry and fluorescence spectroscopy, showing the interaction between chlorogenic acid and the polar site of the biological membrane.…”

Interaction of skullcap (Scutellaria baicalensis Georgi) and buckwheat (Fagopyrum esculentum Moench) extracts with lipid bilayers

“…Similarly small changes in thermotropic parameters were observed for the other extracts investigated by us [38][39][40][41][42][43][44].…”

“…Therefore, alteration of lipid bilayer properties may result not only in antioxidant action of flavonoids but also in affecting the activity of integral proteins and hence influence transport and other membrane-related processes [28][29][30][31][32][33][34][35][36][37][38][39][40][41]. The ability of polyphenols to penetrate into lipid bilayers is undoubtedly crucial to the protection against oxidation [42].…”

Application of the DSC and spectroscopy methods in the analysis of the protective effect of extracts from the blueberry fruit of the genus Vaccinium in relation to the lipid membrane

“…The study was performed at different temperatures for SUVs created with DPPC and treated with selected concentrations of fruit extracts of lowbush, highbush and wild bilberry [22,36,38,39]. Research conducted with the use of DPH probe has shown that tested substances neither change the main phase transition temperature nor fluorescence anisotropy, and thus the fluidity of membranes in the liquid-crystalline phase, as well as in the gel phase, compared with modified liposomes [38,39]. Extract of wild bilberry decreased slightly membrane fluidity in the gel phase, but increased it in the liquidcrystalline state.…”

“…Pretransition temperature (T p ) changes provide evidence for changes rather in the polar part of the membrane that result in loosening its structure [37,41,42]. Calorimetric studies were carried out with the membrane model in the form of MLVs formed of DPPC modified with the extracts and polyphenolic compounds [22,[36][37][38][39]. Calorimetric test results showed little change in T m only for very large concentrations of polyphenolic substances (10 mg mL -1 ), whereas for lower concentrations virtually no change was found.…”