Characterization of the binary mixed monolayers of α-tocopherol with phospholipids at the air-water interface

Does deacclimation reverse the changes in structural/physicochemical properties of the chloroplast membranes that are induced by cold acclimation in oilseed rape?

Winter crops acquire frost tolerance during the process of cold acclimation when plants are exposed to low but non-freezing temperatures that is connected to specific metabolic adjustments. Warm breaks during/after cold acclimation disturb the natural process of acclimation, thereby decreasing frost tolerance and can even result in a resumption of growth. This phenomenon is called deacclimation. In the last few years, studies that are devoted to deacclimation have become more important (due to climate changes) and necessary to be able to understand the mechanisms that occur during this phenomenon. In the acclimation of plants to low temperatures, the importance of plant membranes is indisputable; that is why the main aim of our studies was to answer the question of whether (and to what extent) deacclimation alters the physicochemical properties of the plant membranes. The studies were focused on chloroplast membranes from non-acclimated, cold-acclimated and deacclimated cultivars of winter oilseed rape. The analysis of the membranes (formed from chloroplast lipid fractions) using the Langmuir technique revealed that cold acclimation increased membrane fluidity (expressed as the Alim values), while deacclimation generally decreased the values that were induced by cold. Moreover, because the chloroplast membranes were penetrated by lipophilic molecules such as carotenoids or tocopherols, the relationships between the structure of the lipids and the content of these antioxidants in the chloroplast membranes during the process of the cold acclimation and deacclimation of oilseed rape are discussed.

Perceiving the functions of vitamin E through neutron and X-ray scattering

Take your vitamins, or don't? Vitamin E is one of the few lipophilic vitamins in the human diet and is considered an essential nutrient. Over the years it has proven to be a powerful antioxidant and is commercially used as such, but this association is far from linear in physiology. It is increasingly more likely that vitamin E has multiple legitimate biological roles. Here, we review past and current work using neutron and X-ray scattering to elucidate the influence of vitamin E on key features of model membranes that can translate to the biological function(s) of vitamin E. Although progress is being made, the hundred year-old mystery remains unsolved.

Understanding the Retention of Vaping Additives in the Lungs: Model Lung Surfactant Membrane Perturbation by Vitamin E and Vitamin E Acetate

Deviations from the normal physicochemical and functional properties of pulmonary surfactants are associated with the incidence of lung injury and other respiratory disorders. This study aims to evaluate the alteration of the 2D molecular organization and morphology of pulmonary surfactant model membranes by the electronic cigarette additives α-tocopherol (vitamin E) and α-tocopherol acetate (vitamin E acetate), which have been associated with lung injury, termed e-cigarette or vaping-use-associated lung injury (EVALI). The model membranes used contained a 7:3 molar ratio of DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) and POPG (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol) to which α-tocopherol and α-tocopherol acetate were added to form mixtures of up to 20 mol % additive. The properties of the neat tocopherol additives and DPPC/POPG (7:3) mixtures with increasing molar proportions of additive were evaluated by surface pressure-area isotherms, excess area calculations, Brewster angle microscopy, grazing incidence X-ray diffraction, X-ray reflectivity, and atomic force microscopy. The addition of either additive alters the essential phase balance of the model pulmonary surfactant membrane by generating a greater proportion of the fluid phase. Despite this net fluidization, both tocopherol additives have space-filling effects on the liquid-expanded and condensed phases, yielding negative excess areas in the liquid-expanded phase and reduced tilt angles in the condensed phase. Both tocopherol additives alter the stability of the fluid phase, pushing the eventual collapse of this phase to higher surface pressures than the model membrane in the absence of an additive.

Effect of cationic dendrimer on membrane mimetic systems in the form of monolayer and bilayer

Interactions between a zwitterionic phospholipid, 1, 2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) and four anionic phospholipids dihexadecyl phosphate (DHP), 1, 2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG), 1, 2-dipalmitoyl-sn-glycero-3-phosphate (DPP) and 1, 2-dipalmitoyl-sn-glycero-3-phospho ethanol (DPPEth) in combination with an additional amount of 30 mol% cholesterol were separately investigated at air-buffer interface through surface pressure (π) - area (A) measurements. π-A isotherm derived parameters revealed maximum negative deviation from ideality for the mixtures comprising 30 mol% anionic lipids. Besides the film functionality, structural changes of the monomolecular films at different surface pressures in the absence and presence of polyamidoamine (PAMAM, generation 4), a cationic dendrimer, were visualised through Brewster angle microscopy and fluorescence microscopic studies. Fluidity/rigidity of monolayers were assessed by surface dilatational rheology studies. Effect of PAMAM on the formation of adsorbed monolayer, due to bilayer disintegration of liposomes (DPPC:anionic lipids= 7:3 M/M, and 30 mol% cholesterol) were monitored by surface pressure (π) - time (t) isotherms. Bilayer disintegration kinetics were dependent on lipid head group and chain length, besides dendrimer concentration. Such studies are considered to be an in vitro cell membrane model where the alteration of molecular orientation play important roles in understanding the nature of interaction between the dendrimer and cell membrane. Liposome-dendrimer aggregates were nontoxic to breast cancer cell line as well as in doxorubicin treated MDA-MB-468 cell line suggesting their potential as drug delivery systems.

Unraveling Complex Hysteresis Phenomenon in 1,2-Dipalmitoyl-sn-Glycero-3-Phosphocholine Monolayer: Insight into Factors Influencing Surface Dynamics

This study explores the hysteresis phenomenon in DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) monolayers, considering several variables, including temperature, compression and expansion rates, residence time, and subphase content. The investigation focuses on analyzing the influence of these variables on key indicators such as the π-A isotherm curve, loop area, and compression modulus. By employing the Langmuir-Blodgett technique, the findings reveal that all the examined factors significantly affect the aforementioned parameters. Notably, the hysteresis loop, representing dissipated energy, provides valuable insights into the monolayer's viscoelasticity, molecular packing, phase transition changes, and resistance during the isocycle process. These findings contribute to a comprehensive understanding of the structural and dynamic properties of DPPC monolayers, offering insights into their behavior under varying conditions. Moreover, the knowledge gained from this study can aid in the development of precise models and strategies for controlling and manipulating monolayer properties, with potential applications in drug delivery systems, surface coatings, as well as further investigation into air penetration into alveoli and the blinking mechanism.

Effect of Fluoxetine on the Surface Behavior of the Lipid Monolayers at Different Surface Pressures

Fluoxetine (FLX), used in the clinic to treat depression, is a well-known cationic amphiphilic antidepressant. However, there is a lack of research on the effect of FLX on the surface behavior of lipid monolayers under different surface pressures. In this study, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine/CHOL (DPPC/POPC/CHOL) monolayers were prepared via the Langmuir method, and FLX was added to these monolayers under various surface pressures. The effect of FLX on the surface behavior of DPPC/POPC/CHOL monolayers under various surface pressures was studied using a combination of surface pressure-area isotherms, compressibility modulus-surface pressure curves, and atomic force microscope (AFM). The results showed that the effect of FLX on the lipid monolayers was different under different surface pressures. The interaction between FLX and lipid molecules was weak under low surface pressures, and FLX could easily intercalate between the lipid molecules to inhibit monolayer phase transition. The interaction between FLX and lipid molecules was enhanced and FLX tended to self-aggregate to reduce the monolayer stability when the surface pressure was high. This study lays the foundation for further studies on the interaction between FLX and lipid monolayers.

Effect of Ester Moiety on Structural Properties of Binary Mixed Monolayers of Alpha-Tocopherol Derivatives with DPPC

Phospholipid membranes are ubiquitous components of cells involved in physiological processes; thus, knowledge regarding their interactions with other molecules, including tocopherol ester derivatives, is of great importance. The surface pressure–area isotherms of pure α-tocopherol (Toc) and its derivatives (oxalate (OT), malonate (MT), succinate (ST), and carbo analog (CT)) were studied in Langmuir monolayers in order to evaluate phase formation, compressibility, packing, and ordering. The isotherms and compressibility results indicate that, under pressure, the ester derivatives and CT are able to form two-dimensional liquid-condensed (LC) ordered structures with collapse pressures ranging from 27 mN/m for CT to 44 mN/m for OT. Next, the effect of length of ester moiety on the surface behavior of DPPC/Toc derivatives’ binary monolayers at air–water interface was investigated. The average molecular area, elastic modulus, compressibility, and miscibility were calculated as a function of molar fraction of derivatives. Increasing the presence of Toc derivatives in DPPC monolayer induces expansion of isotherms, increased monolayer elasticity, interrupted packing, and lowered ordering in monolayer, leading to its fluidization. Decreasing collapse pressure with increasing molar ratio of derivatives indicates on the miscibility of Toc esters in DPPC monolayer. The interactions between components were analyzed using additivity rule and thermodynamic calculations of excess and total Gibbs energy of mixing. Calculated excess area and Gibbs energy indicated repulsion between components, confirming their partial mixing. In summary, the mechanism of the observed phenomena is mainly connected with interactions of ionized carboxyl groups of ester moieties with DPPC headgroup moieties where formed conformations perturb alignment of acyl chains, resulting in increasing mean area per molecule, leading to disordering and fluidization of mixed monolayer.

Molecular packing of lipid membranes and action mechanisms of membrane-active peptides

Biomembranes are involved in diverse cellular activities. How membranes and proteins interact in the activities might hinge on the former's physical characteristics, which in turn are influenced by packing of lipid molecules. Yet, the validity of this understanding and its mechanism are unclear. By varying chain saturation of membranes, we explored correlations between lipid packing and peptide-mediated membrane disruption for the antimicrobial peptide, melittin, and amyloidogenic peptide, β-amyloid (1-42). Remarkably, reducing molecular packing flexibility enhanced the membrane disruption, possibly due to a shift from membrane perforation to micellization. A theoretical analysis suggested the energetic basis of this shift. This mechanistically shows that a peptide's mechanism might be dictated not only by its intrinsic properties but also by physical characteristics of membranes.

Embedding an Amphiphilic 4-Hydroxy Thiazole Dye in Langmuir Matrices: Studying Miscibilities with Arylic and Alkylic Matrix Amphiphiles via Langmuir Isotherms and Photo-induced Force Microscopy

We present here a fundamental study on the miscibility between a prototype amphiphilic dye and alkylic and arylic Langmuir monolayers. Embedding dyes in such matrices is crucial for utilizing dyes in any photo-energy conversion process if the involved dyes form aggregates that provide thermal deactivation channels. Because miscibility in Langmuir matrices depends on the blending ratio between the dye and matrix and on the Langmuir film density, as characterized via the surface pressure and the mean molecular area, we employ Langmuir miscibility studies to identify ideal miscibility parameters for each matrix. Atomic force microscopy (AFM) results support miscibility between the dye and both matrix materials at low surface pressures, where smooth and homogeneous films are obtained. AFM and photo-induced force microscopy (PiFM) reveal phase separation if the Langmuir monolayers are deposited at surface pressures above 8 mN/m at which reorientation of the chromophores has been reported. The nanoscale chemical fingerprint mapping enabled by PiFM enables assigning segregated spots to small stearic acid (SA)-enriched domains that have not been detected via AFM, thus demonstrating the value of the IR-spectroscopic contrast provided by PiFM. In this work, we have presented a so far unexploited matrix material (terphenylene carboxylic acid; TPCA) and found it equally suitable for embedding dyes as the standard amphiphile SA. In contrast to SA, TPCA is composed of rigid and electrically conducting π-electron systems, hence, being predestined for aligning dyes in Langmuir matrices and for application in optoelectronic systems.

A Mechanical Mechanism for Vitamin E Acetate in E-cigarette/Vaping-Associated Lung Injury

The outbreak of electronic-cigarette/vaping-associated lung injury (EVALI) has made thousands ill. This lung injury has been attributed to a physical interaction between toxicants from the vaping solution and the pulmonary surfactant. In particular, studies have implicated vitamin E acetate as a potential instigator of EVALI. Pulmonary surfactant is vital to proper respiration through the mechanical processes of adsorption and interface stability to achieve and maintain low surface tension at the air-liquid interface. Using neutron spin echo spectroscopy, we investigate the impact of vitamin E acetate on the mechanical properties of two lipid-only pulmonary surfactant mimics: pure 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and a more comprehensive lipid mixture. It was found that increasing vitamin E acetate concentration nonlinearly increased membrane fluidity and area compressibility to a plateau. Softer membranes would promote adsorption to the air-liquid interface during inspiration as well as collapse from the interface during expiration. These findings indicate the potential for the failure of the pulmonary surfactant upon expiration, attributed to monolayer collapse. This collapse could contribute to the observed EVALI signs and symptoms, including shortness of breath and pneumonitis.

DPPC monolayer response to non-spanning cobalt-cage metallosurfactants: Electrostatic complex formation

A novel series of amphiphilic cobalt-cage derivatives (ACCD), bearing a diaza-crown bridge and varying alkyl chains, facilitate ion transport across biomembrane models via self-aggregation. In this study, compression isotherm analyses and atomic force microscopy (AFM) were used to assess the interactions of these amphiphiles with Langmuir monolayers of dipalmitoylphosphatidylcholine (DPPC) in order to elucidate electrostatic and steric contributions to ion transport. The stability and compressibility of DPPC monolayers are disrupted by ACCD molecules with short (C₁₂) alkyl chains. These top-heavy amphiphiles (large cone angles) create voids at the interface of the hydrophobic/aqueous layer leading to monolayer expansion and packing efficiency of the aliphatic chains is disrupted. Long-tailed analogues (C₁₆, C₁₈) are cohesively integrated into DPPC monolayers due to their smaller cone angles at the interfacial region and increased hydrocarbon compatibility in the hydrophobic region. Thermodynamic data indicate the formation of electrostatic complexes between DPPC and longer-tailed amphiphiles consistent with AFM observations of aggregate structures at the corresponding concentrations.

Applications of Brewster angle microscopy from biological materials to biological systems

Brewster angle microscopy (BAM) is a powerful technique that allows for real-time visualization of Langmuir monolayers. The lateral organization of these films can be investigated, including phase separation and the formation of domains, which may be of different sizes and shapes depending on the properties of the monolayer. Different molecules or small changes within a molecule such as the molecule's length or presence of a double bond can alter the monolayer's lateral organization that is usually undetected using surface pressure-area isotherms. The effect of such changes can be clearly observed using BAM in real-time, under full hydration, which is an experimental advantage in many cases. While previous BAM reviews focused more on selected compounds or compared the impact of structural variations on the lateral domain formation, this review provided a broader overview of BAM application using biological materials and systems including the visualization of amphiphilic molecules, proteins, drugs, extracts, DNA, and nanoparticles at the air-water interface.

Ethanol itself is a holoprosencephaly-inducing teratogen

Ethanol is a teratogen, inducing a variety of structural defects in developing humans and animals that are exposed in utero. Mechanisms of ethanol teratogenicity in specific defects are not well understood. Oxidative metabolism of ethanol by alcohol dehydrogenase or cytochrome P450 2E1 has been implicated in some of ethanol's teratogenic effects, either via production of acetaldehyde or competitive inhibition of retinoic acid synthesis. Generalized oxidative stress in response to ethanol may also play a role in its teratogenicity. Among the developmental defects that ethanol has been implicated in is holoprosencephaly, a failure to define the midline of the forebrain and midface that is associated with a deficiency in Sonic hedgehog pathway function. Etiologically, holoprosencephaly is thought to arise from a complex combination of genetic and environmental factors. We have developed a gene-environment interaction model of holoprosencephaly in mice, in which mutation of the Sonic hedgehog coreceptor, Cdon, synergizes with transient in utero exposure to ethanol. This system was used to address whether oxidative metabolism is required for ethanol's teratogenic activity in holoprosencephaly. We report here that t-butyl alcohol, which is neither a substrate nor an inhibitor of alcohol dehydrogenases or Cyp2E1, is a potent inducer of holoprosencephaly in Cdon mutant mice. Additionally, antioxidant treatment did not prevent ethanol- or t-butyl alcohol-induced HPE in these mice. These findings are consistent with the conclusion that ethanol itself, rather than a consequence of its metabolism, is a holoprosencephaly-inducing teratogen.

Surface properties of polyene glycol phospholipid monolayers

We studied the surface properties of monolayers composed of polyunsaturated conjugated ethylene glycol phospholipids (carotenoid lipids), compared the data with monolayers of dipalmitoylphosphatidylcholine (DPPC) to which carotenoids were added and evaluated the impact of the unsaturated glycol lipids on monolayers with the glycerolipid DPPC. The carotenoid based glycol lipids formed monolayers at the air/water interface. Using the Langmuir method we obtained series of pressure-area (π-A) isotherms and determined the limiting area A per molecule of three glycol lipids, C30:9-C₀A=42.6±1.4Ų, C30:9-C₂A=76.1±2.5Ǻ² and C30:9-C₁₂A=354.0±12.0Ų and their mixtures with DPPC at various mole fraction X. C30:9-C₀ and C30:9-C₂ did not affect significantly the shape of the isotherm, but caused their slight shift toward a lower and larger molecular area, respectively. C30:9-C₁₂ at mole fractions X>0.02 affected the shape of isotherm. The compressibility modulus C_s^-1 of monolayers depended on the surface pressure. C_s^-1 value was substantially higher for DPPC monolayers in comparison with those of pure glycol lipids. At low surface pressure π=5-10mN/m and low mole fractions X<0.02 the glycol lipids formed complexes with DPPC; at higher surface pressure the separation of pure components took place. The dipole potential of the monolayers composed of cationic glycol lipids C30:9-C₂ and C30:9-C₁₂ was higher in comparison with those of zwitterionic DPPC and C30:9-C₀. This may be connected with various contributions of dipole moments of the molecules and their orientation in the monolayer.

Interactions between Phospholipids and Organic Phases: Insights into Lipoproteins and Nanoemulsions

The adsorption of phosphatidylcholines (PCs), dissolved in squalene or squalane as an organic phase, was studied at the interface with water. Using profile analysis tensiometry, the equilibrium adsorption isotherms, minimum molecular interfacial areas, and solubility limits were derived. For squalene, differences in PC solubility and interfacial adsorption were found, depending on PC saturation. Compared to saturated PCs, unsaturated PCs showed a 3-fold-lower interfacial density but up to a 28-fold-higher critical aggregation concentration (CAC). In addition, the solubility limit of unsaturated PC in squalene and in its saturated form squalane diverged by a factor of 739. These findings provided evidence for steric repulsion or π-π interactions of π bonds in both solvent and solute or both effects acting complementarily. In squalane, low solubilities but high interfacial densities were found for all investigated PCs. Changes in fatty acid chain lengths showed that the influence of the increases in entropy and enthalpy on solubility is much smaller than solvent/solute interactions. Oxidation products of squalene lowered the interfacial tension, but increasing concentrations of PC expelled them from the interface. The CAC of saturated PC was increased by oxidation products of squalene whereas that of unsaturated PCs was not. Our findings indicate that the oxidation of triglycerides in lipoprotein cores can lead to increased solubility of saturated phospholipids covering the lipoproteins, contributing to destabilization, coalescence, and terminally the formation of atherosclerotic plaques. The consideration of solvent/solute interactions in molecular modeling may contribute to the interfacial tension and the corresponding kinetic or thermodynamic stability of lipoproteins. Measured areas per molecule prove that PCs form monolayers of different interfacial densities at the squalene/water interface but multilayers at the squalane/water interface. These findings showed that combinations of solvent or solute saturation affect the outcome for nanoemulsions forming either expanded or condensed monolayers or multilayers.

Miscibility of dl-α-tocopherol β-glucoside in DPPC monolayer at air/water and air/solid interfaces

The role of newly synthesized tocopherol glycosidic derivative in modifying molecular organization and phase transitions of phospholipid monolayer at the air/water interface has been investigated. Two-component Langmuir films of dl-α-tocopheryl β-D-glucopyranoside (BG) mixed with dipalmitoyl phosphatidylcholine (DPPC) in the whole range of mole fractions were formed at the water surface. An analysis of surface pressure versus mean molecular area (π-A) isotherms and Brewster angle microscope images showed that the presence of BG molecules changes the structure and packing of the DPPC monolayer in a BG concentration dependent manner. BG molecules incorporated into DPPC monolayer inhibit its liquid expanded to liquid condensed phase transition proportionally to the BG concentration. The monolayers were also transferred onto solid substrates and visualized using an atomic force microscope. The results obtained indicate almost complete miscibility of BG and DPPC in the monolayers at surface pressures present in the biological cell membrane (30-35·10(-3) N·m(-1)) for a BG mole fraction as high as 0.3. This makes the monolayer less packed and more disordered, leading to an increased permeability. The results support our previous molecular dynamics simulation data.

The impact of auxins used in assisted phytoextraction of metals from the contaminated environment on the alterations caused by lead(II) ions in the organization of model lipid membranes

Auxins are successfully used to improve phytoextraction efficiency of metal ions from the contaminated environment, however, the mechanism of their activity in this field is not explained. Auxins are known to exert various biochemical alterations in the plant membranes and cells, but their activity involves also direct interactions with lipids leading to changes in membrane organization. Following the suggestion that the auxins-induced modifications in membrane properties alleviate toxic effect of metal ions in this paper we have undertaken the comparative studies on the effect of metal ions and metal ions/auxins mixtures on model membrane systems. The experiments were done on lipid monolayers differing in their composition spread on water subphase and on Pb(2+), Indole-3-acetic acid (IAA), 1-Naphthaleneacetic acid (NAA) and Pb(2+)/IAA and Pb(2+)/NAA water solutions. The analysis of the collected data suggests that metal ions and auxins can change fluidity of the lipid systems and weaken the interactions between monolayer components. This manifested in the increase of the mean area per molecule and the excess area per molecule values for the films on Pb(2+), auxins as well as Pb(2+)/auxin solutions as compared to the values on pure water subphase. However, the presence of auxin in the mixture with lead(II) ions makes the alterations induced by sole metal ions weaker. This effect was more pronounced for the membranes of a higher packing. Thus it was proposed that auxins may enhance phytoextraction of metal ions by weakening their destabilizing effect on membrane.

Antagonistic effects of α-tocopherol and ursolic acid on model bacterial membranes

α-tocopherol (Toc), the most active component of vitamin E can exert antagonistic effects disabling the therapy of cancers and bacterial infections. Such antagonisms were observed also between Toc and bioactive pentacyclic triterpenes (PT) exhibiting anticancer and antibacterial properties. Both Toc and PT are water-insoluble membrane active substances. Thus, our idea was to emulate their interactions with model Escherichia coli membranes. E. coli inner membranes were selected for the experiments because their lipid composition is quite simple and well characterized and the two main components are phosphatidylethanolamine and phosphatidylglycerol. As a model of E. coli membranes we applied Langmuir monolayers formed by the E. coli total extract of polar lipids (Etotal) as well as by the main lipid components: phosphatidylethanolamine (POPE) and phosphatidylglycerol (ECPG). The antagonistic effects of ursolic acid (Urs) and Toc were investigated with the application of ternary Langmuir monolayers formed by Urs, Toc and one of the phospholipids POPE or ECPG. Our studies indicated that the affinities of Urs and Toc towards the POPE molecule are comparable; whereas there are profound differences in the interactions of Urs and Toc with ECPG. Thus, the model experiments prove that in the case of E. coli membrane, the differences in the interactions between Urs and Toc with the anionic bacterial phosphatidylglycerol can be the key factor responsible for the antagonistic effects observed between PT and Toc in vivo.

Physicochemical aspects of reaction of ozone with galactolipid and galactolipid-tocopherol layers

The impact of reaction of galactolipids with ozone on the physicochemical properties of their monolayers was examined. In Megli and Russo (Biochim Biophys Acta, 1778:143–152, 2008), Cwiklik and Jungwirth (Chem Phys Lett, 486:99–103, 2010), Jurkiewicz et al. (Biochim Biophys Acta, 1818:2388–2402, 2012), Khabiri et al. (Chem Phys Lett, 519:93–99, 2012), and Conte et al. (Biochim Biophys Acta, 1828:510–517, 2013), the properties of layers formed from model mixtures composed of chosen lipids and selected oxidation products were studied, whereas in this work, question was raised as to how the oxidation reactions taking place in situ affect the physical properties of the galactolipid layers. So, set experiment should take into account the effect of all reaction products. The mechanical characteristics of monolayers of monogalactosyldiacyl-glycerol (MGDG) and digalactosyldiacylglycerol (DGDG) were determined by Langmuir trough technique, and the electrical properties of liposomes formed from these lipids by measuring their electrophoretic mobility. Considerable loss of galactolipid molecules forming monolayers was found at ozone concentrations (in aqueous medium) higher than 0.1 ppm with a stronger effect measured for MGDG. That goes along with the greater amounts of MDA found in the extracts of oxidized MGDG films compared with DGDG. Based on this, it was concluded that an additional galactose group present in DGDG molecules acts protectively under oxidative conditions. The surface tension of the solutions (of small volume) contacting the oxidized galactolipids films was significantly reduced, indicating the presence of soluble in polar media, surface active reaction products. The presence of α-tocopherol in mixtures with tested galactolipids at a molar ratio of lipid to tocopherol equal to 1.7:1 caused some inhibition of lipid oxidation, reducing the decrease of amount of lipid particles forming the monolayer. Here, also protective effect of α-tocopherol was greater for the MGDG compared to DGDG.