Lutein and some of its uses

Lutein, a very useful thing for human biology is; lutein is an unsaturated polyenic hydrocarbons, which composed of eight isoprene residues forming the carbon chain with 40 carbon atoms and two hydroxyl groups in β-ion rings is. Lutein belongs to the group of carotenoids along with beta-carotene and lycopene. While the beta-carotene accumulates in the skin to provide a golden-yellow color, lutein accumulates preferentially in the macula lutea, protecting the retina from oxidative damage from UVR. Lutein and zeaxanthin, structural isomers, are non-provitamin A carotenoids that are measurable in human blood and tissues. Lutein and zeaxanthin have been identified as the xanthophylls that constitute the macular pigment of the human retina. The relative concentration of lutein to zeaxanthin in the macula is distinctive. Zeaxanthin is more centralized and lutein predominates toward the outer area of the macula. It has anti-inflammatory, antioxidant, anticarcinogenic, photoprotection and properties and also acts to improve skin elasticity. Lutein is physiologically delivered to the retina, and it has been thought to protect the retina by reducing the cytotoxic influence of light stimuli by blocking blue light and by suppressing ROS as an antioxidant. Lutein, zeaxanthin, β-carotene or lycopene are dietary carotenoids with antioxidant properties present in human milk. In particular, the effectiveness of lutein to neutralize oxidants and to modulate inflammatory processes has been demonstrated in several experimental studies. Sasaki et al. showed that, in the STZ-induced diabetes model, including lutein as a constant component of the diet significantly reduced the intensity of DHE staining in the neural retina, without reducing the blood sugar level. A putative xanthophyll-binding protein has also been described, which may explain the high variability of people to accumulate these carotenoids into eye tissues. Increased lutein intake from both food sources and supplements is positively correlated with increased macular pigment density, which is theorized to lower risk for macular degeneration.

The main natural sources of lutein on this planet Earth are vegetables and green vegetables such as kale, spinach, chicory, celery, lettuce, fresh herbs, and egg yolk. Lutein and zeaxanthin are concentrated in the macula or central region of the retina, and are referred to as macular pigment. In addition to their role as antioxidants, lutein and zeaxanthin are believed to limit retinal oxidative damage by absorbing incoming blue light and/or quenching reactive oxygen species. Most retrospective and prospective studies indicate that intake or blood levels of lutein and zeaxanthin do not modulate risk of cortical, nuclear, or posterior subcapsular cataract, although a Finnish study showed that those with the highest plasma levels of lutein and zeaxanthin had a reduced risk of nuclear cataract. Prospective data from epidemiological studies also suggest that elevated lutein and zeaxanthin status is associated with diminished risk of nuclear cataract.

Carotenoids are lipophilic isoprenoid compounds comprised of a polyene backbone containing a conjugated chain of alternating double and single carbon-carbon bonds that may or may not be cyclised at one/both ends. Carotenoids are an essential component of all photosynthetic organisms due to their eminent photoprotective and antioxidant properties. However, their occurrence is not restricted to plants, algae, and cyanobacteria, as some fungi and non-photosynthetic bacteria can synthesize carotenoids as well, and many animals rely on food-borne carotenoids as visual pigments, antioxidants, or colorants. The carotenoids belong to the isoprenoids and their basic structure is made up of eight isoprene units, resulting in a C₄₀ backbone. Carotenoid pigments are classified based on their chemical composition as either carotenes (hydrocarbon carotenoids) or xanthophylls (oxygen-containing carotenoids). All of the carotenoids are biosynthesized from the hydrocarbon phytoene (or 4,4′-diapophytoene in a minor case). Phytoene and 4,4′-diapophytoene are generated from two molecules of geranylgeranyl diphosphate (GGPP) and farnesyl diphosphate (FPP), respectively. These hydrocarbon precursors are dehydrogenated to form conjugated double bonds, frequently cyclized, and subjected to series of modifications to form a large variety of xanthophylls. Antioxidant micronutrients, such as vitamins and carotenoids, exist in abundance in fruit and vegetables and have been known to contribute to the body's defense against reactive oxygen species.

Lutein and zeaxanthin are found in the lens and are thought to protect cells in the eye against oxidative damage, seemingly protecting the eye and preventing cataracts. Eating plenty of fruits and vegetables, good sources of many antioxidants including carotenoids, is a preventative measure for many diseases. Lutein and zeaxanthin are xanthophylls that are principally responsible for the yellow-orange color of fruits and vegetables and are also found in several cyanobacteria. These carotenoids are selectively accumulated in the macula of the eye and hinder the development of age-related macular degeneration.

References

Nutraceuticals for Healthy Skin Aging

Oxidative stress biomarkers in the preterm infant

The Role of Nutrition in Age-Related Eye Diseases

Lutein and Oxidative Stress-Mediated Retinal Neurodegeneration in Diabetes

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Lutein and some of its uses