Related Experiment Video
Updated: Jul 19, 2025
09:35
Measurement of Carotenoids in Perifovea using the Macular Pigment Reflectometer
Published on: January 29, 2020
7.9K
How Do Xanthophylls Protect Lipid Membranes from Oxidative Damage?
Renata Welc-Stanowska1,2, Rafal Pietras3, Bohun Mielecki3,4
1Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, Poland.
The Journal of Physical Chemistry Letters
|August 14, 2023
Summary
Lutein and zeaxanthin protect biomembranes by quenching singlet oxygen and forming an oxygen barrier. Their photoisomerization in the retina regulates light filtration and photoprotection.
Area of Science:
- Biochemistry
- Photochemistry
- Cell Biology
Background:
- Carotenoids, like lutein and zeaxanthin, are known antioxidants.
- Their role in protecting biomembranes from oxidative stress is crucial.
- Understanding their mechanism in lipid environments is essential for photoprotection.
Purpose of the Study:
- To investigate the antioxidant activity of lutein and zeaxanthin in biomembranes.
- To determine their efficacy in quenching singlet oxygen.
- To elucidate their role in modulating molecular oxygen penetration into lipid membranes.
Main Methods:
- Utilized lipid vesicles to mimic biomembranes.
- Employed a singlet oxygen-sensitive fluorescent probe to monitor quenching.
- Applied fluorescence lifetime imaging microscopy for spatial analysis.
- Used electron paramagnetic resonance oximetry to assess oxygen barrier properties.
Main Results:
- Lutein and zeaxanthin effectively quenched singlet oxygen generated by photosensitization.
- Xanthophylls demonstrated a significant barrier effect against molecular oxygen permeation into lipid membranes.
- The 13-cis configuration of xanthophylls exhibited a greater oxygen barrier effect than the all-trans form.
- Results align with observed trans-cis photoisomerization in the human retina.
Conclusions:
- Xanthophyll photoisomerization is a key regulatory mechanism for retinal photoprotection.
- This process modulates light filtration in the macula.
- It enhances antioxidant defense by quenching singlet oxygen and limiting oxygen diffusion into membranes.
More Related Videos
11:28Isolating and Incorporating Light-Harvesting Antennas from Diatom Cyclotella Meneghiniana in Liposomes with Thylakoid Lipids
Published on: August 28, 2018
7.8K
07:29Cell-free Biochemical Fluorometric Enzymatic Assay for High-throughput Measurement of Lipid Peroxidation in High Density Lipoprotein
Published on: October 12, 2017
9.3K
Related Concept Videos
01:20Radical Autoxidation
2.2K
The oxidation of an organic compound in the presence of air or oxygen is called autoxidation. For example, cumene reacts with oxygen to form hydroperoxide. Autoxidation involves initiation, propagation, and termination steps. Many organic compounds are susceptible to autoxidation—especially ethers in the presence of oxygen, which form hydroperoxides. Even though this reaction is slow, old ether bottles contain small amounts of peroxide, which leads to laboratory explosions during ether...
2.2K
01:17Oxidation of Phenols to Quinones
3.1K
In the presence of oxidizing agents, phenols are oxidized to quinones. Quinones can be easily reduced back to phenols using mild reducing agents. The electron-donating hydroxyl group enhances the reactivity of the aromatic ring, enabling oxidation of the ring even in the absence of an α hydrogen.
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox...
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox...
3.1K
01:31Lipid-derived Compounds in the Human Body
4.4K
Fats and lipids are crucial components in the human body. Some lipid-derived compounds, such as fat-soluble vitamins, eicosanoids, lipoproteins, and glycolipids, also play unique roles to support various biological processes .
Fat-soluble Vitamins
Fat-soluble vitamins, including vitamins A, D, E, and K, are required in minimal quantities, but their deficiencies can lead to severely abnormal physiological conditions. For example, vitamin A deficiency can cause night blindness, dry skin,...
Fat-soluble Vitamins
Fat-soluble vitamins, including vitamins A, D, E, and K, are required in minimal quantities, but their deficiencies can lead to severely abnormal physiological conditions. For example, vitamin A deficiency can cause night blindness, dry skin,...
4.4K
01:18Lipids: Dietary Sources and Requirements
838
Lipids are an essential component of a balanced human diet. Triglycerides, which make up the majority of dietary lipids, are found in both saturated fats—commonly present in meat, dairy products, and certain tropical plants like coconut, and hydrogenated oils such as margarine and baking shortenings (trans fats)—and unsaturated fats, which are abundant in seeds, nuts, olive oil, and most vegetable oils. The main sources of cholesterol include egg yolks, various meats and organ...
838
01:20Sulfur Assimilation
44
Sulfur is an essential element in biological systems, contributing to synthesizing key biomolecules, including amino acids such as cysteine and methionine, and cofactors such as coenzyme A and biotin. Microorganisms primarily assimilate sulfur as sulfate (SO₄²⁻) from the environment, which must undergo a series of biochemical transformations before it can be incorporated into cellular components. As sulfate is highly oxidized, it must undergo assimilatory sulfate reduction to...
44
01:19Pigmentation
2.5K
The color of the skin is influenced by a number of pigments, including melanin, carotene, and hemoglobin. Recall that melanin is produced by cells called melanocytes, which are found scattered throughout the stratum basale of the epidermis. The melanin is transferred to the keratinocytes via melanosomes.
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
2.5K