Membrane perturbing properties of natural phenolic and resorcinolic lipids (original) (raw)
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Changes Caused by Fruit Extracts in the Lipid Phase of Biological and Model Membranes
Food biophysics, 2011
The aim of the study was to determine changes incurred by polyphenolic compounds from selected fruits in the lipid phase of the erythrocyte membrane, in liposomes formed of erythrocyte lipids and phosphatidylcholine liposomes. In particular, the effect of extracts from apple, chokeberry, and strawberry on the red blood cell morphology, on packing order in the lipid hydrophilic phase, on fluidity of the hydrophobic phase, as well as on the temperature of phase transition in DPPC liposomes was studied. In the erythrocyte population, the proportions of echinocytes increased due to incorporation of polyphenolic compounds. Fluorimetry with a laurdan probe indicated increased packing density in the hydrophilic phase of the membrane in presence of polyphenolic extracts, the highest effect being observed for the apple extract. Using the fluorescence probes DPH and TMA-DPH, no effect was noted inside the hydrophobic phase of the membrane, as the lipid bilayer fluidity was not modified. The p...
Impact of selected polyphenolics on the structural properties of model lipid membranes – a review
International Journal of Food Studies, 2017
This review is a presentation of data gathered on the interactions of several polyphenolics (i.e., phenolic acids, stilbenes, flavonoids) with lipid bilayers of different lipid compositions. These polyphenolics have been investigated through a combination of fluorescence spectroscopy, electron paramagnetic resonance spectroscopy, and differential scanning calorimetry, to detect changes in membrane fluidity. Among the investigated phenolic acids, the least polar phenolic acid, p-coumaric acid, has the greatest effect on lipid membrane structure. It appears to have a greater ability to cross membranes by passive transport than more polar phenolic acids. On the other hand, among the flavonoids that have been studied, the anthocyanins cyanidin 3-glucoside and its aglycone are inactive. All of the flavonols tested, except for epigallocatechin-3-gallate, promote small decreases in membrane fluidity. Computer simulation of electron paramagnetic resonance spectra for flavonoids indicated tw...
Chemistry and Physics of Lipids, 1984
The steady state fluorescence anisotropy (r s) of l-acyl-2-cis parinaroyl phosphatidylcholine (PnPC) was compared with that of diphenylhexatriene (DPH) in a variety of model-and biological membrane systems. The fluorescence anisotropy of both probes responded similarly to temperature changes and variations in the acyl chain composition in phosphatidylcholine (PC) liposomes. The presence of proteins and cholesterol increased r s for both DPH and PnPC in the biological membranes as compared to the isolated polar membrane lipids. Comparison of DPH and PnPC in dipalmitoyl-PC-liposomes with and without 50 mol% cholesterol, showed at temperatures above the phase transition of pure dipalmitoyl-PC the presence of cholesterol increased the rs-value for DPH strongly, whereas the rs-value for PnPC was much less affected. In the cholesterol-rich erythrocyte membrane as well as in microsomes from Morris hepatoma 7787, which have an increased cholesterol content as compared to normal rat liver microsomes, the r s of DPH was higher than that of PnPC. No large differences between the rs-values of both probes were evident in the normal cholesterol-poor rat liver microsomes. These effects are discussed in terms of structural differences between the probes and variation of cholesterol content. Alterations in the fatty acid composition of PC present in human erythrocyte membranes were introduced with the aid of a PC-specific transfer protein. Fluorescence anisotropy values of both probes hardly changed upon enrichment of the red cell membrane with either dipalmitoyl PC or 1-paimitoyl-2-arachidonyl PC.
Flavonols - new fluorescent membrane probes for studying the interdigitation of lipid bilayers
Biochimica et Biophysica Acta (BBA) - Biomembranes, 1998
Two flavonols, 3-hydroxy-4'-dimethylaminoflavone (FME) and 3-hydroxy-4'-(15-azacrown-5) flavone (FRC) have been investigated as new fluorescence probes for studying the formation of the interdigitated gel phase in lipid bilayers. The formation of the interdigitated gel phase in the saturated symmetrical phosphatidylcholines (PCs) and phosphatidylethanol (Peth) in the presence of ethanol has been well studied. The present study examines the behavior of these new probes in PC-ethanol and Peth-ethanol systems, as well as in PC-cholesterol and Peth-cholesterol vesicles. The present results demonstrate that both flavonols give distinctively different spectra in interdigitated lipids compared to non-interdigitated lipids, when examined in lipids in which the interdigitation behavior is known. This makes them useful for determinations of the structural state of unknown lipids, and for following the transitions between interdigitated and non-interdigitated phases. However, in the presence of cholesterol, only FCR gave appropriate indications of interdigitation. The results with FME in the presence of cholesterol were not consistent with the known behavior of the lipids examined; instead, FME appears to be located preferentially in the cholesterol-rich non-interdigitated regions of the bilayer.
Biochimica et Biophysica Acta (BBA) - Biomembranes, 2014
Common hop (Humulus lupulus) constitutes a source of numerous prenylated chalcones such as xanthohumol (XH) and flavanones such as 8-prenylnaringenin (8-PN) and isoxanthohumol (IXH). Range of their biological activities includes estrogenic, anti-inflammatory, anti-infective, anti-cancer, and antioxidant activities. The aim of the present work was to characterize the influence of prenylated polyphenols on model 1,2-dipalmitoyl-snglycero-3-phosphocholine (DPPC) membranes by means of differential scanning calorimetry (DSC), fluorescence and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopies. All studied compounds intercalated into DPPC bilayers and decreased its melting temperature as recorded by DSC, Laurdan and Prodan fluorescence, and ATR-FTIR. Polyphenols interacted mainly with glycerol backbone and acyl chain region of membrane. Magnitude of the induced effect correlated both with lipophilicity and molecular shape of the studied compounds. Elbow-shaped 8-PN and IXH were locked at polar-apolar region with their prenyl chains penetrating into hydrophobic part of the bilayer, while relatively planar XH molecule adopted linear shape that resulted in its deeper insertion into hydrophobic region. Additionally, by means of DSC and Laurdan fluorescence IXH was demonstrated to induce lateral phase separation in DPPC bilayers in gel-like state. It was assumed that IXHrich and IXH-poor microdomains appeared within membrane. Present work constitutes the first experimental report describing interactions of prenylated hop polyphenols with phospholipid model membranes.
Permeability and Structural Changes Induced by Phytochrome in Lipid Vesicles
Photochemistry and Photobiology, 1982
This paper describes a method for rapidly monitoring early changes in electrolyte permeability induced by phytochrome from salt-loaded liposomes. The method allows for the continuous monitoring of low-level ion efflux from liposomes by measuring the conductivity of a liposome suspension medium which has osmotic and chemical potentials that promote a slow. passive efflux of the compartmented electrolytes. The addition of the far-red absorbing form of phytochrome (Pfr) to this system at 20°C immediately producesefflux rates which are 2-3 times greater than if the red-absorbing form (Pr) is added. This differential effect is not evident at 4°C and varies with the lipid composition of the liposomes. Under conditions in which Pfr induces a '-fold greater change in the electrolyte permeability of liposomes than Pr. only about 18% more "'I-labeled Pfr than 1251-labeled Pr binds to the liposomes. At equimolar concentrations. the photochromic small peptide of phytochrome (60 000 dalton monomer) and the more native 'large' phytochrome (120000 dalton subunits) induced equivalent changes in the electrolyte permeability of liposomes. N o differential leakage of ATP, glucose, or trvpsin from liposomes was observed after Pr and Pfr reacted with vesicles enclosing these substances. The Pfr form of phytochrome promoted greater turbidity in liposome suspensions and a greater degree of aggregation and/or vesiclc fusion than Pr. The kinetics of these changes suggested that they were not the hasis ot the differential permeability effects of Pr and Pfr.
Use of liposomes to evaluate the role of membrane interactions on antioxidant activity
Analytica Chimica Acta, 2007
In this study the possibility of using liposomes as membrane mimetic systems was evaluated to estimate the antioxidant properties of oxicams and establish a relationship between the interactions of the drugs with the membrane and their consequent antioxidant activity. Different experiments were performed covering the study of the protective effect of oxicams in lipid peroxidation induced by the peroxyl radical (ROO • ) derived from 2,2azobis(2-amidinopropane) dihydrochloride (AAPH) and using two fluorescence probes with distinct lipophilic properties. Lipid peroxidation using the hydrophilic probe fluorescein was evaluated in lipid and aqueous media. Lipid systems labelled with the fluorescent probe diphenylhexatriene propionic acid (DPH-PA) were used to assess the effects of the drugs on membrane peroxidation simultaneously by fluorescence intensity decay and changes in membrane fluidity by steady-state anisotropy measurements. The use of different probes and liposomes as membrane mimetic systems allowed to conclude that membrane lipoperoxidation is related not only to the scavenging characteristics of the antioxidants but also to their ability to interact with the lipid bilayers.
The Journal of Membrane Biology, 2014
The aim of the present research was to determine the effect of blue honeysuckle fruit and leaf extracts components on the physical properties of erythrocyte and lipid membranes and assess their antioxidant properties. The HPLC analysis showed that the extracts are rich in polyphenol anthocyanins in fruits and flavonoids in leaves. The results indicate that both extracts have antioxidant activity and protect the red blood cell membrane against oxidation induced by UVC irradiation and AAPH. The extracts do not induce hemolysis and slightly increase osmotic resistance of erythrocytes. The research showed that extracts components are incorporated mainly in the external part of the erythrocyte membrane, inducing the formation of echinocytes. The values of generalized polarization and fluorescence anisotropy indicate that the extracts polyphenols alter the packing arrangement of the hydrophilic part of the erythrocyte and lipid membranes, without changing the fluidity of the hydrophobic part. The DSC results also show that the extract components do not change the main phase transition temperature of DPPC membrane. Studies of electric parameters of membranes modified by the extracts showed that they slightly stabilize lipid membranes and do not reduce their specific resistance or capacity. Examination of IR spectra indicates small changes in the degree of hydration in the hydrophilic region of liposomes under the action of the extracts. The location of polyphenolic compounds in the hydrophilic part of the membrane seems to constitute a protective shield of the cell against other substances, the reactive forms of oxygen in particular. Keywords Blue honeysuckle polyphenol extracts Á HPLC analysis Á Antioxidant activity Á Erythrocyte membrane anisotropy Á Model lipid membranes Á Lipid phase transition Abbreviations AAPH 2,2 0-azobis (2-methylpropionamidine) dihydrochloride DPH 1,6-Diphenyl-1,3,5-hexatriene DPH-PA (1,6-Diphenyl-1,3,5-hexatriene) propionic acid DPPC 1,2-Dipalmitoyl-sn-glycero-3-phosphatidylcholine DSC Differential scanning calorimetry EPC Egg yolk lecithin GP Generalized polarization Laurdan 6-Dodecanoyl-2-dimethylaminonaphthalene Prodan 6-Propionyl-2-dimethylaminonaphthalene BLM Black lipid membranes RBCL Red blood cell lipids MLV Multilamellar vesicles SUV Small unilamellar vesicles BHL Blue honeysuckle leaf extract BHF Blue honeysuckle fruit extract
Biochimica et Biophysica Acta (BBA) - Biomembranes, 1995
The water-soluble antioxidant, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic (Trolox), (4-14C)-labelled, was used to trace its location in the aqueous and lipid phases of liposomes. Trolox was found to partition 20 to 25% into the lipid phase of multilamellar (MLV) and 38-46% into the lipid phase of unilamellar (ULV) egg lecithin liposomes. Trolox and its oxidation products partition readily (40%) into the lipid phase of dilinoleoylphosphatidylcholine (DLPC) MLV liposomes during inhibited peroxidation, thermally initiated by azo-bis(2,4-dimethylvaleronitrile) (ADVN). The time-course of the consumption of Trolox during peroxidation of DLPC liposomes, initiated by ADVN, was followed by separation and analyses of [4-~4C]Trolox and its oxidation products. Such studies showed that the consumption of Trolox followed the profile of the inhibition of oxygen uptake. This indicates that Trolox can be used in quantitative studies of membrane peroxidation; for example, to measure the rate of chain initiation (Ri). The product distribution of hydroperoxides, the 9-and 13-cis, trans (c,t) and trans, trans (t,t) isomers, formed during inhibited peroxidation of linoleate, in DLPC and methyl linoleate in dimyristoyl PC (DMPC) liposomes was determined by HPLC of the derived hydroxy methyl esters. The c,t/t,t (kinetic/thermodynamic) ratios were related to the antioxidant activity of the inhibitors. Both Trolox and a-tocopherol (vitamin E) gave relatively high initial c,t/t,t ratios (6.6 and 7.1) during inhibited peroxidation of DLPC, initiated by water-soluble azo-bis(2-amidinopropane • HCI) (ABAP). High initial c,t/t,t ratios (6.2) were also observed for ce-tocopherol-inhibited peroxidation of DLPC liposomes, initiated by lipid-soluble ADVN. On the other hand, the combination of Trolox with ADVN-initiated peroxidation of DLPC or of methyl linoleate in DMPC gave relatively low initial c,t/t,t ratios of 3.5 and 1.3. These results are interpreted in terms of the relative hydrogen atom donating ability of the antioxidants and the homogeneity of the system used. The 9/13 ratios of hydroperoxides were constant (0.9 to 1.0) in all experiments and did not give evidence for preferential trapping by Trolox of peroxyls at the 9-position.
The effect of nonadec(en)ylresorcinol on the fluidity of liposome and erythrocyte membranes
Biochimica et Biophysica Acta (BBA) - Biomembranes, 1988
The effect of alk(en)ylresorcinol homologs (5-(n-nonadecyl)-and 5-(z-nonadecenyl)resorcino|) on the mobility of S-doxyl-and l2-doxylstearate spin probes incorporated into DMPC, DMPC-cholesterol and erythrocyte membranes was studied. It was found that both homologs affect the propeńies of hydrophobic environment of the membranes: (r) In DMPC vesicles both homologs induce an increase in the order parameter of S-doxylstearate at temperatures of Ę and above. (2) At higher concentrations of both homo|ogs a decrease in mobility of the l2-doxylstearate was also observed. In the presence of cholesterol in the liposome membrane the influence of alk(en)ylresorcinols on the mobiliĘ of spin probes was much gTeater, depending on the cholesterol content and the position of the probe in the bilayer. (4) In natural membranes (erythrocyte ghosts) both alkyland alkenylresorcinols induced a decrease of mobiliĘ in the region of l2-doxylstearate as well as in the region closer to the polar head groups of lipids (5-doxylstearate). Biochimica et Biophysica Actą 944 (1988) 465-472 Elsevier BBA 74165