Interaction of alcohol with phospholipid membrane: NMR and XRD investigations on DPPC–hexanol system (2023)

FAQs

How does alcohol affect the phospholipid bilayer? ›

At high concentrations, alcohols reduce bilayer stability (12,21) and break down the lipid bilayer barrier properties, causing increased ion permeability (14,15).

Ethanol is able to form hydrogen bonds with the lipids in the bilayer (see Hydrogen Bonding of Alcohol to Lipids, below), and these hydrogen bonds reduce the order parameter of the lipid hydrocarbon chains. The combination of these aspects results in an easy penetration of ethanol through the bilayer.

As the ethanol concentration increases, membrane permeability will increase. If the ethanol concentration is high enough, enough phospholipids will dissolve to cause the plasma membrane to disintegrate completely which will kill the cell.

Ethanol treatment leads to increased membrane fluidity and to changes in membrane protein composition. It can also interact directly with membrane proteins, causing conformational changes and thereby influencing their function. The cytotoxic action may include an increased level of oxidative stress.

These negative biological effects of alcohol suggest that alcohol interferes with the transmission of messages throughout the body. By affecting potassium levels in the cell membrane, alcohol interferes with a neuron firing. This pro- cess which occurs throughout the brain is often referred to as an action potential.

Although the alcohol has an amphiphilic nature, its hydrophobicity is limited; it can pass through the bilayer. Besides this, ethanol molecules condense near the interface region between lipids and water.

Like ethyl ether, ethanol is a polar molecule and will experience dipole-dipole interactions. Why are the dipole-dipole forces in ethanol stronger than those in ethyl ether? The especially strong intermolecular forces in ethanol are a result of a special class of dipole-dipole forces called hydrogen bonds.

Unless solubilized by the presence of other lipids, polar lipids, such as phospholipids and glycosphingolipids, are only slightly soluble in hydrocarbons, but they dissolve readily in more polar solvents like methanol, ethanol or chloroform.

Phospholipid bilayer

Hydrogen bonding and electrostatic attractions (ionic bonds) occur between the hydrophilic groups of phospholipids and the aqueous solution. We say that hydrophobic forces cause the bilayer to form, and the other weak forces stabilize the bilayer.

Abstract. Ethanol disrupts the physical structure of cell membranes. The most fluid membranes, including those that are low in cholesterol, are the most easily disordered by ethanol.

Does alcohol affect permeability? ›

At high concentrations, alcohols reduce bilayer stability (12, 21) and break down the lipid bilayer barrier properties, causing increased ion permeability (14, 15).

Posted April 22, 2021. The permeability of a membrane is affected by temperature, the types of solutes present and the level of cell hydration.

Ethanol diffuses through cell membranes

The biological membrane structure allows small, uncharged molecules like ethanol, CO2 and H2O to pass directly through the membrane by the process of diffusion.

Hence, as the ethanol concentration increases, the permeability of the plasma membrane will increase accordingly and the transmission of light will decrease as there is an increase of the betacyanin leaking.

Small polar molecules, such as water and ethanol, can also pass through membranes, but they do so more slowly. On the other hand, cell membranes restrict diffusion of highly charged molecules, such as ions, and large molecules, such as sugars and amino acids.

From here, it is important to note that hyperpolarization is the phase most affected by the introduction of alcohol.

The reinforcing effects of alcohol are mediated by several neurochemical systems, with dopamine and serotonin playing major roles in reward and the gamma-aminobutyric acid-benzodiazepine receptor system playing a major role in negative reinforcement.

Alcohol facilitates esterification of the accumulated fatty acids to triglycerides, phospholipids, and cholesterol esters, all of which accumulate in the liver. The accumulated lipids are disposed of in part as serum lipoprotein, resulting in moderate hyperlipemia.

Alcohol consumption significantly increased HDL2-c and reduced TG, total cholesterol, LDL-c, sdLDL-c, and apoB levels. For each of these lipids a non-linear trend was observed.

What can pass through a phospholipid membrane? ›

Gases, hydrophobic molecules, and small polar uncharged molecules can diffuse through phospholipid bilayers.

In a mixture of ethanol and water, hydrogen bonding is the strongest intermolecular force between molecules. Hydrogen bonding occurs when a partially negative oxygen atom of ethanol is attracted to the partially positive hydrogen end of another molecule in the same mixture.

The four key intermolecular forces are as follows: Ionic bonds > Hydrogen bonding > Van der Waals dipole-dipole interactions > Van der Waals dispersion forces.

Between the molecules of alcohol as well as water, hydrogen bonding is one of the interactive forces between the molecules. When alcohol and water are mixed together, new H-bonds also develop between alcohol and water molecules but these are weaker than the previous ones.

Ethanol is an interesting molecule. It is polar or hydrophilic (water-loving) due to the presence of the terminal hydroxyl group, so it dissolves in water.

Phospholipids are amphipathic; they contains both polar regions (phosphate and alcohol group) and nonpolar regions (fatty acids).

The bilayer is held together by weak hydrophobic interactions between the tails. Hydrophilic / hydrophobic layers restrict the passage of many substances. Individual phospholipids can move within the bilayer, allowing for membrane fluidity and flexibility.

Phospholipids do not interact with water because water is polar and lipids are nonpolar. The polar heads interact with water; the nonpolar tails do not. Phospholipids dissolve in water.

When phospholipids are mixed with water, they spontaneously rearrange themselves to form the lowest free-energy configuration. This means that the hydrophobic regions find ways to remove themselves from water, while the hydrophilic regions interact with water. The resulting structure is called a lipid bilayer.

Which of the three alcohols seems to affect membranes the most? ›

1-Propanol seems to affect membranes the most, as there is more pigment (cellular damage) at any concentration of alcohol.

Permeability of phospholipid bilayers. Small uncharged molecules can diffuse freely through a phospholipid bilayer. However, the bilayer is impermeable to larger polar molecules (such as glucose and amino acids) and to ions.

The two main players in the cell membrane that affects its permeability are: The predominance of saturated or unsaturated fatty acids in the membrane: Shorter chain lengths and higher unsaturated fatty acids increase the membrane's permeability.

In this article, it is shown that membrane permeability to water and solutes is dependent on the temperature, medium osmolality, types of solutes present, cell hydration level, and absence or presence of ice.

The most important parameters that govern transmembrane diffusion are polarity and size. For example, small nonpolar gases such as O₂ , CO₂ , and N₂ , and small polar molecules such as ethanol cross lipid membranes rapidly.

Experiments on phospholipid membranes have shown that alcohols can induce an interdigitated phase and at high concentration even promote the assembly of some lipids into non-bilayer structures within the membrane interior.

Effect of Solvents on Cell Membranes. Solvents such as ethanol increase membrane permeability. Lipids dissolve in alcohol, therefore, the phospholipids in a cell membrane will easily dissolve in solutions such as ethanol. As a result, the cell membrane becomes more fluid and permeable as it starts to break down.

Exposure to alcohol significantly alters the developmental trajectory of progenitor cells and fundamentally compromises tissue formation (i.e., histogenesis). Emerging research suggests that ethanol can impair mammalian development by interfering with the execution of molecular programs governing differentiation.

THE green colouring matter of plants is a wax-like material of complex chemical structure to which the name chlorophyll was given by Pelletier and Caventou in 1817. It is insoluble in water but soluble in alcohol, ether and other organic solvents.

Alcohol facilitates esterification of the accumulated fatty acids to triglycerides, phospholipids, and cholesterol esters, all of which accumulate in the liver. The accumulated lipids are disposed of in part as serum lipoprotein, resulting in moderate hyperlipemia.

What affects the phospholipid bilayer? ›

Three key factors influence cell membrane fluidity: temperature, cholesterol, and the kind of fatty acids in the phospholipids that form the cell membrane. These factors alter the space and interaction between the phospholipids, and how this affects the fluidity of the cell membrane.

The hydrocarbon chains are forced between water molecules, breaking hydrogen bonds between those water molecules. The -OH ends of the alcohol molecules can form new hydrogen bonds with water molecules, but the hydrocarbon "tail" does not form hydrogen bonds.

Ethanol diffuses across the biological membrane by moving through the lipid bilayer itself and by moving through water pores and spaces created by proteins. The driving force to move alcohol across a membrane by diffusion is the concentration gradient.

Can alcohol affect a cholesterol test? Absolutely.

The emulsion test is a method to determine the presence of lipids using wet chemistry. The procedure is for the sample to be suspended in ethanol, allowing lipids present to dissolve (lipids are soluble in alcohols).

Alcohol contains a lot of sugar and calories, and thus can elevate triglycerides in the body. Consuming large amounts of alcohol can increase the release of VLDL, increase the flow of free fatty acids to the liver from fat tissue, and impede the body's ability to break down fat.

Gases, hydrophobic molecules, and small polar uncharged molecules can diffuse through phospholipid bilayers. Larger polar molecules and charged molecules cannot.

Cholesterol stabilizes hemifused phospholipid bilayer vesicles.

alcohols. …is referred to as a hydrophilic (“water-loving”) group, because it forms hydrogen bonds with water and enhances the solubility of an alcohol in water. Methanol, ethanol, n-propyl alcohol, isopropyl alcohol, and t-butyl alcohol are all miscible with water.

Hexanol would have a greater solubility in water than hexane because of the ability of hexanol to form hydrogen bonds with water. This is due to the presence of the hydroxyl group in hexanol.

Is ethanol hydrophilic or hydrophobic? ›

Ethanol is soluble in water

It is polar or hydrophilic (water-loving) due to the presence of the terminal hydroxyl group, so it dissolves in water.

Ethanol is able to form hydrogen bonds with the lipids in the bilayer (see Hydrogen Bonding of Alcohol to Lipids, below), and these hydrogen bonds reduce the order parameter of the lipid hydrocarbon chains. The combination of these aspects results in an easy penetration of ethanol through the bilayer.

Small polar molecules, such as water and ethanol, can also pass through membranes, but they do so more slowly. On the other hand, cell membranes restrict diffusion of highly charged molecules, such as ions, and large molecules, such as sugars and amino acids.