Β-Carotene

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β-Carotene
Beta-Carotin.svg
Beta-carotene-from-xtal-3D-bs-17.png
Beta-carotene-from-xtal-3D-sf.png
B-Carotene powder.jpg
Names
IUPAC name
β,β-Carotene
Systematic IUPAC name
1,1′-[(1E,3E,5E,7E,9E,11E,13E,15E,17E)-3,7,12,16-Tetramethyloctadeca-1,3,5,7,9,11,13,15,17-nonaene-1,18-diyl]bis(2,6,6-trimethylcyclohex-1-ene)
Other names
Betacarotene (INN), β-Carotene, [3] Food Orange 5, Provitamin A
Identifiers
3D model (JSmol)
3DMet
1917416
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.027.851 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 230-636-6
E number E160a (colours)
KEGG
PubChem CID
UNII
  • InChI=1S/C40H56/c1-31(19-13-21-33(3)25-27-37-35(5)23-15-29-39(37,7)8) 17-11-12-18-32(2)20-14-22-34(4)26-28-38-36(6)24-16-30-40(38,9) 10/h11-14,17-22,25-28H,15-16,23-24,29-30H2,1-10H3 X mark.svgN
    Key: OENHQHLEOONYIE-UHFFFAOYSA-N X mark.svgN
  • CC2(C)CCCC(\C)=C2\C=C\C(\C)=C\C=C\C(\C)=C\C=C\C=C(/C)\C=C\C=C(/C)\C=C\C1=C(/C)CCCC1(C)C
Properties
C40H56
Molar mass 536.888 g·mol−1
AppearanceDark orange crystals
Density 1.00 g/cm3 [4]
Melting point 183 °C (361 °F; 456 K) [4]
decomposes [5]
Boiling point 654.7 °C (1,210.5 °F; 927.9 K)
at 760 mmHg (101324 Pa)
Insoluble
Solubility Soluble in CS2, benzene, CHCl3, ethanol
Insoluble in glycerin
Solubility in dichloromethane 4.51 g/kg (20 °C) [6] = 5.98 g/L (given BCM density of 1.3266 g/cm3 at 20°C)
Solubility in hexane 0.1 g/L
log P 14.764
Vapor pressure 2.71·10−16 mmHg
1.565
Pharmacology
A11CA02 ( WHO ) D02BB01 ( WHO )
Hazards
GHS labelling:
GHS-pictogram-exclam.svg
Warning
H315, H319, H412
P264, P273, P280, P302+P352, P305+P351+P338, P321, P332+P313, P337+P313, P362, P501
NFPA 704 (fire diamond)
NFPA 704.svgHealth 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chlorideFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
1
0
Flash point 103 °C (217 °F; 376 K) [5]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

β-Carotene (beta-carotene) is an organic, strongly colored red-orange pigment abundant in fungi, [7] plants, and fruits. It is a member of the carotenes, which are terpenoids (isoprenoids), synthesized biochemically from eight isoprene units and thus having 40 carbons.

Dietary β-carotene is a provitamin A compound, converting in the body to retinol (vitamin A). [8] In foods, it has rich content in carrots, pumpkin, spinach, and sweet potato. [8] It is used as a dietary supplement and may be prescribed to treat erythropoietic protoporphyria, an inherited condition of sunlight sensitivity. [9]

β-carotene is the most common carotenoid in plants. [8] When used as a food coloring, it has the E number E160a. [10] : 119  The structure was deduced in 1930. [11]

Isolation of β-carotene from fruits abundant in carotenoids is commonly done using column chromatography. It is industrially extracted from richer sources such as the algae Dunaliella salina . [12] The separation of β-carotene from the mixture of other carotenoids is based on the polarity of a compound. β-Carotene is a non-polar compound, so it is separated with a non-polar solvent such as hexane. [13] Being highly conjugated, it is deeply colored, and as a hydrocarbon lacking functional groups, it is lipophilic.

Provitamin A activity

Plant carotenoids are the primary dietary source of provitamin A worldwide, with β-carotene as the best-known provitamin A carotenoid. [8] Others include α-carotene and β-cryptoxanthin. [8] Carotenoid absorption is restricted to the duodenum of the small intestine. One molecule of β-carotene can be cleaved by the intestinal enzyme β,β-carotene 15,15'-monooxygenase into two molecules of vitamin A. [8] [14] [15]

Absorption, metabolism and excretion

As part of the digestive process, food-sourced carotenoids must be separated from plant cells and incorporated into lipid-containing micelles to be bioaccessible to intestinal enterocytes. [8] If already extracted (or synthetic) and then presented in an oil-filled dietary supplement capsule, there is greater bioavailability compared to that from foods. [16]

At the enterocyte cell wall, β-carotene is taken up by the membrane transporter protein scavenger receptor class B, type 1 (SCARB1). Absorbed β-carotene is then either incorporated as such into chylomicrons or first converted to retinal and then retinol, bound to retinol binding protein 2, before being incorporated into chylomicrons. [8] The conversion process consists of one molecule of β-carotene cleaved by the enzyme beta-carotene 15,15'-dioxygenase, which is encoded by the BCO1 gene, into two molecules of retinal. [8] When plasma retinol is in the normal range the gene expression for SCARB1 and BCO1 are suppressed, creating a feedback loop that suppresses β-carotene absorption and conversion. [16]

The majority of chylomicrons are taken up by the liver, then secreted into the blood repackaged into low density lipoproteins (LDLs). [8] From these circulating lipoproteins and the chylomicrons that bypassed the liver, β-carotene is taken into cells via receptor SCARB1. Human tissues differ in expression of SCARB1, and hence β-carotene content. Examples expressed as ng/g, wet weight: liver=479, lung=226, prostate=163 and skin=26. [16]

Once taken up by peripheral tissue cells, the major usage of absorbed β-carotene is as a precursor to retinal via symmetric cleavage by the enzyme beta-carotene 15,15'-dioxygenase, which is encoded by the BCO1 gene. [8] A lesser amount is metabolized by the mitochondrial enzyme beta-carotene 9',10'-dioxygenase, which is encoded by the BCO2 gene. The products of this asymmetric cleavage are two beta-ionone molecules and rosafluene. BCO2 appears to be involved in preventing excessive accumulation of carotenoids; a BCO2 defect in chickens results in yellow skin color due to accumulation in subcutaneous fat. [17] [18]

Conversion factors

For counting dietary vitamin A intake, β-carotene may be converted either using the newer retinol activity equivalents (RAE) or the older international unit (IU). [8]

Retinol activity equivalents (RAEs)

Since 2001, the US Institute of Medicine uses retinol activity equivalents (RAE) for their Dietary Reference Intakes, defined as follows: [8] [19]

RAE takes into account carotenoids' variable absorption and conversion to vitamin A by humans better than and replaces the older retinol equivalent (RE) (1 µg RE = 1 µg retinol, 6 µg β-carotene, or 12 µg α-carotene or β-cryptoxanthin). [19] RE was developed 1967 by the United Nations/World Health Organization Food and Agriculture Organization (FAO/WHO). [20]

International Units

Another older unit of vitamin A activity is the international unit (IU). [8] Like retinol equivalent, the international unit does not take into account carotenoid variable absorption and conversion to vitamin A by humans, as well as the more modern retinol activity equivalent. Unfortunately, food and supplement labels still generally use IU, but IU can be converted to the more useful retinol activity equivalent as follows: [19]

Dietary sources

The average daily intake of β-carotene is in the range 2–7 mg, as estimated from a pooled analysis of 500,000 women living in the US, Canada, and some European countries. [21] Beta-carotene is found in many foods and is sold as a dietary supplement. [8] β-Carotene contributes to the orange color of many different fruits and vegetables. Vietnamese gac (Momordica cochinchinensis Spreng.) and crude palm oil are particularly rich sources, as are yellow and orange fruits, such as cantaloupe, mangoes, pumpkin, and papayas, and orange root vegetables such as carrots and sweet potatoes. [8]

The color of β-carotene is masked by chlorophyll in green leaf vegetables such as spinach, kale, sweet potato leaves, and sweet gourd leaves. [8] [22]

The U.S. Department of Agriculture lists foods high in β-carotene content: [23]

FoodBeta-carotene

Milligrams per 100 g

Sweet potato, skinned, boiled9.4
Carrot juice9.3
Carrots, raw or boiled9.2
Kale, boiled8.8
Pumpkin, canned6.9
Spinach, canned5.9

No dietary requirement

Government and non-government organizations have not set a dietary requirement for β-carotene. [16]

Side effects

Excess β-carotene is predominantly stored in the fat tissues of the body. [8] The most common side effect of excessive β-carotene consumption is carotenodermia, a physically harmless condition that presents as a conspicuous orange skin tint arising from deposition of the carotenoid in the outermost layer of the epidermis. [8] [9] [16] [24]

Carotenosis

Carotenoderma, also referred to as carotenemia, is a benign and reversible medical condition where an excess of dietary carotenoids results in orange discoloration of the outermost skin layer. [8] It is associated with a high blood β-carotene value. This can occur after a month or two of consumption of beta-carotene rich foods, such as carrots, carrot juice, tangerine juice, mangos, or in Africa, red palm oil. β-carotene dietary supplements can have the same effect. The discoloration extends to palms and soles of feet, but not to the white of the eye, which helps distinguish the condition from jaundice. Carotenodermia is reversible upon cessation of excessive intake. [25] Consumption of greater than 30 mg/day for a prolonged period has been confirmed as leading to carotenemia. [16] [26]

No risk for hypervitaminosis A

At the enterocyte cell wall, β-carotene is taken up by the membrane transporter protein scavenger receptor class B, type 1 (SCARB1). Absorbed β-carotene is then either incorporated as such into chylomicrons or first converted to retinal and then retinol, bound to retinol binding protein 2, before being incorporated into chylomicrons. The conversion process consists of one molecule of β-carotene cleaved by the enzyme beta-carotene 15,15'-dioxygenase, which is encoded by the BCO1 gene, into two molecules of retinal. When plasma retinol is in the normal range the gene expression for SCARB1 and BCO1 are suppressed, creating a feedback loop that suppresses absorption and conversion. Because of these two mechanisms, high intake will not lead to hypervitaminosis A. [16]

Drug interactions

β-Carotene can interact with medication used for lowering cholesterol. [8] Taking them together can lower the effectiveness of these medications and is considered only a moderate interaction. [8] Bile acid sequestrants and proton-pump inhibitors can decrease absorption of β-carotene. [27] Consuming alcohol with β-carotene can decrease its ability to convert to retinol and could possibly result in hepatotoxicity. [28]

β-Carotene and lung cancer in smokers

Chronic high doses of β-carotene supplementation increases the probability of lung cancer in smokers. [8] [29] The effect is specific to supplementation dose as no lung damage has been detected in those who are exposed to cigarette smoke and who ingest a physiological dose of β-carotene (6 mg), in contrast to high pharmacological dose (30 mg). Therefore, the oncology from β-carotene is based on both cigarette smoke and high daily doses of β-carotene. [8] [30]

Increases in lung cancer may be due to the tendency of β-carotene to oxidize, [31] and may hasten oxidation more than other food colors such as annatto. A β-carotene breakdown product suspected of causing cancer at high dose is trans-β-apo-8'-carotenal (common apocarotenal), which has been found in one study to be mutagenic and genotoxic in cell cultures which do not respond to β-carotene itself. [32]

Additionally, supplemental, high-dose β-carotene may increase the risk of prostate cancer, intracerebral hemorrhage, and cardiovascular and total mortality in people who smoke cigarettes or have a history of high-level exposure to asbestos. [8] [9]

Industrial sources

β-carotene is industrially made either by total synthesis (see Retinol § Industrial synthesis) or by extraction from biological sources such as vegetables, microalgae (especially Dunaliella salina), and genetically-engineered microbes. The synthetic path is low-cost and high-yield. [33]

Research

Medical authorities generally recommend obtaining beta-carotene from food rather than dietary supplements. [8] A 2013 meta-analysis of randomized controlled trials concluded that high-dosage (≥9.6 mg/day) beta-carotene supplementation is associated with a 6% increase in the risk of all-cause mortality, while low-dosage (<9.6 mg/day) supplementation does not have a significant effect on mortality. [34] Research is insufficient to determine whether a minimum level of beta-carotene consumption is necessary for human health and to identify what problems might arise from insufficient beta-carotene intake. [35] However, a 2018 meta-analysis mostly of prospective cohort studies found that both dietary and circulating beta-carotene are associated with a lower risk of all-cause mortality. The highest circulating beta-carotene category, compared to the lowest, correlated with a 37% reduction in the risk of all-cause mortality, while the highest dietary beta-carotene intake category, compared to the lowest, was linked to an 18% decrease in the risk of all-cause mortality. [36]

Macular degeneration

Age-related macular degeneration (AMD) represents the leading cause of irreversible blindness in elderly people. AMD is an oxidative stress, retinal disease that affects the macula, causing progressive loss of central vision. [37] β-carotene content is confirmed in human retinal pigment epithelium. [16] Reviews reported mixed results for observational studies, with some reporting that diets higher in β-carotene correlated with a decreased risk of AMD whereas other studies reporting no benefits. [38] Reviews reported that for intervention trials using only β-carotene, there was no change to risk of developing AMD. [8] [38] [39]

Cancer

A meta-analysis concluded that supplementation with β-carotene does not appear to decrease the risk of cancer overall, nor specific cancers including: pancreatic, colorectal, prostate, breast, melanoma, or skin cancer generally. [8] [40] High levels of β-carotene may increase the risk of lung cancer in current and former smokers. [8] [41] This is likely because beta-carotene is unstable in cigarette smoke-exposed lungs where it forms oxidized metabolites that can induce carcinogen-bioactivating enzymes. [42] Results are not clear for thyroid cancer. [43]

Cataract

A Cochrane review looked at supplementation of β-carotene, vitamin C, and vitamin E, independently and combined, on people to examine differences in risk of cataract, cataract extraction, progression of cataract, and slowing the loss of visual acuity. These studies found no evidence of any protective effects afforded by β-carotene supplementation on preventing and slowing age-related cataract. [44] A second meta-analysis compiled data from studies that measured diet-derived serum beta-carotene and reported a not statistically significant 10% decrease in cataract risk. [45]

Erythropoietic protoporphyria

High doses of β-carotene (up to 180 mg per day) may be used as a treatment for erythropoietic protoporphyria, a rare inherited disorder of sunlight sensitivity, without toxic effects. [8] [9]

Food drying

Foods rich in caretenoid dyes show discoloration upon drying. This is due to thermal degradation of caretenoids, possibly via isomerization and oxidation reactions. [46]

See also

Related Research Articles

<span class="mw-page-title-main">Carotene</span> Class of compounds

The term carotene (also carotin, from the Latin carota, "carrot") is used for many related unsaturated hydrocarbon substances having the formula C40Hx, which are synthesized by plants but in general cannot be made by animals (with the exception of some aphids and spider mites which acquired the synthesizing genes from fungi). Carotenes are photosynthetic pigments important for photosynthesis. Carotenes contain no oxygen atoms. They absorb ultraviolet, violet, and blue light and scatter orange or red light, and (in low concentrations) yellow light.

<span class="mw-page-title-main">Lycopene</span> Carotenoid pigment

Lycopene is an organic compound classified as a tetraterpene and a carotene. Lycopene is a bright red carotenoid hydrocarbon found in tomatoes and other red fruits and vegetables.

Vitamin E is a group of eight fat soluble compounds that include four tocopherols and four tocotrienols. Vitamin E deficiency, which is rare and usually due to an underlying problem with digesting dietary fat rather than from a diet low in vitamin E, can cause nerve problems. Vitamin E is a fat-soluble antioxidant which may help protect cell membranes from reactive oxygen species. Worldwide, government organizations recommend adults consume in the range of 3 to 15 mg per day. As of 2016, consumption was below recommendations according to a worldwide summary of more than one hundred studies that reported a median dietary intake of 6.2 mg per day for alpha-tocopherol.

Tocopherols are a class of organic compounds comprising various methylated phenols, many of which have vitamin E activity. Because the vitamin activity was first identified in 1936 from a dietary fertility factor in rats, it was named tocopherol, from Greek τόκοςtókos 'birth' and φέρεινphérein 'to bear or carry', that is 'to carry a pregnancy', with the ending -ol signifying its status as a chemical alcohol.

<span class="mw-page-title-main">Vitamin A</span> Essential nutrient

Vitamin A is a fat-soluble vitamin and an essential nutrient for animals. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinal, retinoic acid, and several provitamin (precursor) carotenoids, most notably beta-carotene. Vitamin A has multiple functions: it is essential for embryo development and growth, for maintenance of the immune system, and for vision, where it combines with the protein opsin to form rhodopsin – the light-absorbing molecule necessary for both low-light and color vision.

<span class="mw-page-title-main">Retinol</span> Chemical compound

Retinol, also called vitamin A1, is a fat-soluble vitamin in the vitamin A family that is found in food and used as a dietary supplement. Retinol or other forms of vitamin A are needed for vision, cellular development, maintenance of skin and mucous membranes, immune function and reproductive development. Dietary sources include fish, dairy products, and meat. As a supplement it is used to treat and prevent vitamin A deficiency, especially that which results in xerophthalmia. It is taken by mouth or by injection into a muscle. As an ingredient in skin-care products, it is used to reduce wrinkles and other effects of skin aging.

<span class="mw-page-title-main">Abetalipoproteinemia</span> Medical condition

Abetalipoproteinemia is a disorder characterized by abnormal absorption of fat and fat-soluble vitamins from food. It is caused by a mutation in microsomal triglyceride transfer protein resulting in deficiencies in the apolipoproteins B-48 and B-100, which are used in the synthesis and exportation of chylomicrons and VLDL respectively. It is not to be confused with familial dysbetalipoproteinemia.

<span class="mw-page-title-main">Multivitamin</span> Dietary supplement containing vitamins

A multivitamin is a preparation intended to serve as a dietary supplement with vitamins, dietary minerals, and other nutritional elements. Such preparations are available in the form of tablets, capsules, pastilles, powders, liquids, or injectable formulations. Other than injectable formulations, which are only available and administered under medical supervision, multivitamins are recognized by the Codex Alimentarius Commission as a category of food.

The ionones, from greek ἴον ion "violet", are a series of closely related chemical substances that are part of a group of compounds known as rose ketones, which also includes damascones and damascenones. Ionones are aroma compounds found in a variety of essential oils, including rose oil. β-Ionone is a significant contributor to the aroma of roses, despite its relatively low concentration, and is an important fragrance chemical used in perfumery. The ionones are derived from the degradation of carotenoids.

<span class="mw-page-title-main">Lutein</span> Yellow organic pigment created by plants

Lutein is a xanthophyll and one of 600 known naturally occurring carotenoids. Lutein is synthesized only by plants, and like other xanthophylls is found in high quantities in green leafy vegetables such as spinach, kale and yellow carrots. In green plants, xanthophylls act to modulate light energy and serve as non-photochemical quenching agents to deal with triplet chlorophyll, an excited form of chlorophyll which is overproduced at very high light levels during photosynthesis. See xanthophyll cycle for this topic.

<span class="mw-page-title-main">Apocarotenal</span> Chemical compound

Apocarotenal, or trans-β-apo-8'-carotenal, is a carotenoid found in spinach and citrus fruits. Like other carotenoids, apocarotenal plays a role as a precursor of vitamin A, even though it has 50% less pro-vitamin A activity than β-carotene. The empirical chemical formula for apocarotenal is C30H40O.

<span class="mw-page-title-main">Zeaxanthin</span> Chemical compound

Zeaxanthin is one of the most common carotenoids in nature, and is used in the xanthophyll cycle. Synthesized in plants and some micro-organisms, it is the pigment that gives paprika, corn, saffron, goji (wolfberries), and many other plants and microbes their characteristic color.

<span class="mw-page-title-main">Hypervitaminosis A</span> Toxic effects of ingesting too much vitamin A

Hypervitaminosis A refers to the toxic effects of ingesting too much preformed vitamin A. Symptoms arise as a result of altered bone metabolism and altered metabolism of other fat-soluble vitamins. Hypervitaminosis A is believed to have occurred in early humans, and the problem has persisted throughout human history. Toxicity results from ingesting too much preformed vitamin A from foods, supplements, or prescription medications and can be prevented by ingesting no more than the recommended daily amount.

Megavitamin therapy is the use of large doses of vitamins, often many times greater than the recommended dietary allowance (RDA) in the attempt to prevent or treat diseases. Megavitamin therapy is typically used in alternative medicine by practitioners who call their approach orthomolecular medicine. Vitamins are useful in preventing and treating illnesses specifically associated with dietary vitamin shortfalls, but the conclusions of medical research are that the broad claims of disease treatment by advocates of megavitamin therapy are unsubstantiated by the available evidence. It is generally accepted that doses of any vitamin greatly in excess of nutritional requirements will result either in toxicity or in the excess simply being metabolised; thus evidence in favour of vitamin supplementation supports only doses in the normal range. Critics have described some aspects of orthomolecular medicine as food faddism or even quackery. Research on nutrient supplementation in general suggests that some nutritional supplements might be beneficial, and that others might be harmful; several specific nutritional therapies are associated with an increased likelihood of the condition they are meant to prevent.

<span class="mw-page-title-main">Carotenosis</span> Skin discoloration caused by carotenoids

Carotenosis is a benign and reversible medical condition where an excess of dietary carotenoids results in orange discoloration of the outermost skin layer. The discoloration is most easily observed in light-skinned people and may be mistaken for jaundice. Carotenoids are lipid-soluble compounds that include alpha- and beta-carotene, beta-cryptoxanthin, lycopene, lutein, and zeaxanthin. The primary serum carotenoids are beta-carotene, lycopene, and lutein. Serum levels of carotenoids vary between region, ethnicity, and sex in the healthy population. All are absorbed by passive diffusion from the gastrointestinal tract and are then partially metabolized in the intestinal mucosa and liver to vitamin A. From there they are transported in the plasma into the peripheral tissues. Carotenoids are eliminated via sweat, sebum, urine, and gastrointestinal secretions. Carotenoids contribute to normal-appearing human skin color, and are a significant component of physiologic ultraviolet photoprotection.

<span class="mw-page-title-main">Vitamin A deficiency</span> Disease resulting from low Vitamin A concentrations in the body

Vitamin A deficiency (VAD) or hypovitaminosis A is a lack of vitamin A in blood and tissues. It is common in poorer countries, especially among children and women of reproductive age, but is rarely seen in more developed countries. Nyctalopia is one of the first signs of VAD, as the vitamin has a major role in phototransduction; but it is also the first symptom that is reversed when vitamin A is consumed again. Xerophthalmia, keratomalacia, and complete blindness can follow if the deficiency is more severe.

β-Cryptoxanthin is a natural carotenoid pigment. It has been isolated from a variety of sources including the fruit of plants in the genus Physalis, orange rind, papaya, egg yolk, butter, apples, and bovine blood serum.

<span class="mw-page-title-main">Beta-carotene 15,15'-dioxygenase</span> Mammalian protein found in Homo sapiens

In enzymology, beta-carotene 15,15'-dioxygenase, (EC 1.13.11.63) is an enzyme with systematic name beta-carotene:oxygen 15,15'-dioxygenase (bond-cleaving). In human it is encoded by the BCO1 gene. This enzyme catalyses the following chemical reaction

Vitamins occur in a variety of related forms known as vitamers. A vitamer of a particular vitamin is one of several related compounds that performs the functions of said vitamin and prevents the symptoms of deficiency of said vitamin.

A co-carcinogen is a chemical that promotes the effects of a carcinogen in the production of cancer. Usually, the term is used to refer to chemicals that are not carcinogenic on their own, such that an equivalent amount of the chemical is insufficient to initiate carcinogenesis. A chemical can be co-carcinogenic with other chemicals or with nonchemical carcinogens, such as UV radiation.

References

  1. 1 2 Hursthouse MB, Nathani SC, Moss GP (2004). "CSD Entry: CARTEN02". Cambridge Structural Database: Access Structures. Cambridge Crystallographic Data Centre. doi:10.5517/cc8j3mh . Retrieved 9 July 2022.
  2. 1 2 Senge MO, Hope H, Smith KM (1992). "Structure and Conformation of Photosynthetic Pigments and Related Compounds 3. Crystal Structure of β-Carotene". Z. Naturforsch. C . 47 (5–6): 474–476. doi: 10.1515/znc-1992-0623 . S2CID   100905826.
  3. ↑ "SciFinder – CAS Registry Number 7235-40-7" . Retrieved 21 October 2009.
  4. 1 2 Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). CRC Press. p. 3.94. ISBN   978-1439855119.
  5. 1 2 Sigma-Aldrich Co., β-Carotene. Retrieved on 27 May 2014.
  6. ↑ "Beta-carotene". PubChem, US National Library of Medicine. 27 January 2024. Retrieved 31 January 2024.
  7. ↑ Lee SC, Ristaino JB, Heitman J (13 December 2012). "Parallels in Intercellular Communication in Oomycete and Fungal Pathogens of Plants and Humans". PLOS Pathogens. 8 (12): e1003028. doi: 10.1371/journal.ppat.1003028 . PMC   3521652 . PMID   23271965.
  8. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 "α-Carotene, β-Carotene, β-Cryptoxanthin, Lycopene, Lutein, and Zeaxanthin". Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis. October 2023. Retrieved 31 January 2024.
  9. 1 2 3 4 "Beta-carotene". MedlinePlus, National Library of Medicine, US National Institutes of Health. 27 January 2023. Retrieved 31 January 2024.
  10. ↑ Milne, George W. A. (2005). Gardner's commercially important chemicals: synonyms, trade names, and properties. New York: Wiley-Interscience. ISBN   978-0-471-73518-2.
  11. ↑ Karrer P, Helfenstein A, Wehrli H (1930). "Pflanzenfarbstoffe XXV. Über die Konstitution des Lycopins und Carotins". Helvetica Chimica Acta . 13 (5): 1084–1099. doi:10.1002/hlca.19300130532.
  12. ↑ States4439629 United Statesexpired 4439629,Rüegg, Rudolf,"Extraction Process for Beta-Carotene",published 27 March 1984, assigned to Hoffmann-La Roche Inc.
  13. ↑ Mercadante AZ, Steck A, Pfander H (January 1999). "Carotenoids from guava (Psidium guajava l.): isolation and structure elucidation". Journal of Agricultural and Food Chemistry. 47 (1): 145–51. doi:10.1021/jf980405r. PMID   10563863.
  14. ↑ Biesalski HK, Chichili GR, Frank J, von Lintig J, Nohr D (2007). Conversion of β-carotene to retinal pigment. Vitamins & Hormones. Vol. 75. pp. 117–30. doi:10.1016/S0083-6729(06)75005-1. ISBN   978-0-12-709875-3. PMID   17368314.
  15. ↑ Eroglu A, Harrison EH (July 2013). "Carotenoid metabolism in mammals, including man: formation, occurrence, and function of apocarotenoids". J Lipid Res. 54 (7): 1719–30. doi: 10.1194/jlr.R039537 . PMC   3679377 . PMID   23667178.
  16. 1 2 3 4 5 6 7 8 von Lintig J (2020). "Carotenoids". In BP Marriott, DF Birt, VA Stallings, AA Yates (eds.). Present Knowledge in Nutrition, Eleventh Edition. London, United Kingdom: Academic Press (Elsevier). pp. 531–49. ISBN   978-0-323-66162-1.
  17. ↑ Babino D, Palczewski G, Widjaja-Adhi MA, Kiser PD, Golczak M, von Lintig J (October 2015). "Characterization of the Role of β-Carotene 9,10-Dioxygenase in Macular Pigment Metabolism". J Biol Chem. 290 (41): 24844–57. doi: 10.1074/jbc.M115.668822 . PMC   4598995 . PMID   26307071.
  18. ↑ Wu L, Guo X, Wang W, Medeiros DM, Clarke SL, Lucas EA, et al. (November 2016). "Molecular aspects of β, β-carotene-9', 10'-oxygenase 2 in carotenoid metabolism and diseases". Exp Biol Med (Maywood). 241 (17): 1879–1887. doi:10.1177/1535370216657900. PMC   5068469 . PMID   27390265.
  19. 1 2 3 Institute of Medicine (US) Panel on Micronutrients (2001). Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium and Zinc. (free download): National Academy Press. doi:10.17226/10026. ISBN   978-0-309-07279-3. PMID   25057538. S2CID   44243659.
  20. ↑ Requirement of Vitamin A, Thiamine, Riboflavin and Niacin. FAO Food and Nutrition Series B. Rome: Food and Agriculture Organization/World Health Organization. 1967.
  21. ↑ Koushik A, Hunter DJ, Spiegelman D, Anderson KE, Buring JE, Freudenheim JL, et al. (November 2006). "Intake of the major carotenoids and the risk of epithelial ovarian cancer in a pooled analysis of 10 cohort studies". International Journal of Cancer. 119 (9): 2148–54. doi: 10.1002/ijc.22076 . PMID   16823847. S2CID   22948131.
  22. ↑ Kidmose U, Edelenbos M, Christensen LP, Hegelund E (October 2005). "Chromatographic determination of changes in pigments in spinach (Spinacia oleracea L.) during processing". Journal of Chromatographic Science. 43 (9): 466–72. doi: 10.1093/chromsci/43.9.466 . PMID   16212792.
  23. ↑ "USDA National Nutrient Database for Standard Reference, Release 28" (PDF). 28 October 2015. Retrieved 5 February 2022.
  24. ↑ Blaner WS (2020). "Vitamin A". In BP Marriott, DF Birt, VA Stallings, AA Yates (eds.). Present Knowledge in Nutrition, Eleventh Edition. London, United Kingdom: Academic Press (Elsevier). pp. 73–92. ISBN   978-0-323-66162-1.
  25. ↑ Maharshak N, Shapiro J, Trau H (March 2003). "Carotenoderma--a review of the current literature". Int J Dermatol. 42 (3): 178–81. doi: 10.1046/j.1365-4362.2003.01657.x . PMID   12653910. S2CID   27934066.
  26. ↑ Nasser Y, Jamal Z, Albuteaey M (11 August 2021). "Carotenemia". StatPearls. doi:10.1007/s00253-001-0902-7. PMID   30521299. S2CID   22232461.
  27. ↑ Meschino Health. "Comprehensive Guide to Beta-Carotene" . Retrieved 29 May 2012.
  28. ↑ Leo MA, Lieber CS (June 1999). "Alcohol, vitamin A, and beta-carotene: adverse interactions, including hepatotoxicity and carcinogenicity". The American Journal of Clinical Nutrition. 69 (6): 1071–85. doi: 10.1093/ajcn/69.6.1071 . PMID   10357725.
  29. ↑ Tanvetyanon T, Bepler G (July 2008). "Beta-carotene in multivitamins and the possible risk of lung cancer among smokers versus former smokers: a meta-analysis and evaluation of national brands". Cancer. 113 (1): 150–7. doi: 10.1002/cncr.23527 . PMID   18429004. S2CID   33827601.
  30. ↑ Russel, R.M. (2002). "Beta-carotene and lung cancer". Pure Appl. Chem. 74 (8): 1461–1467. CiteSeerX   10.1.1.502.6550 . doi:10.1351/pac200274081461. S2CID   15046337.
  31. ↑ Hurst JS, Saini MK, Jin GF, Awasthi YC, van Kuijk FJ (August 2005). "Toxicity of oxidized beta-carotene to cultured human cells". Experimental Eye Research. 81 (2): 239–43. doi:10.1016/j.exer.2005.04.002. PMID   15967438.
  32. ↑ Alija AJ, Bresgen N, Sommerburg O, Siems W, Eckl PM (May 2004). "Cytotoxic and genotoxic effects of beta-carotene breakdown products on primary rat hepatocytes". Carcinogenesis. 25 (5): 827–31. doi: 10.1093/carcin/bgh056 . PMID   14688018.
  33. ↑ Singh RV, Sambyal K (June 2022). "An overview of β-carotene production: Current status and future prospects". Food Bioscience. 47: 101717. doi:10.1016/j.fbio.2022.101717. S2CID   248252973.
  34. ↑ Bjelakovic G, Nikolova D, Gluud C (2013). "Meta-regression analyses, meta-analyses, and trial sequential analyses of the effects of supplementation with beta-carotene, vitamin A, and vitamin E singly or in different combinations on all-cause mortality: do we have evidence for lack of harm?". PLOS ONE. 8 (9): e74558. Bibcode:2013PLoSO...874558B. doi: 10.1371/journal.pone.0074558 . PMC   3765487 . PMID   24040282.
  35. ↑ Stargrove M (20 December 2007). Herb, nutrient, and drug interactions : clinical implications and therapeutic strategies (1 ed.). Mosby. ISBN   978-0323029643.
  36. ↑ Jayedi A, Rashidy-Pour A, Parohan M, Zargar MS, Shab-Bidar S (2018). "Dietary Antioxidants, Circulating Antioxidant Concentrations, Total Antioxidant Capacity, and Risk of All-Cause Mortality: A Systematic Review and Dose-Response Meta-Analysis of Prospective Observational Studies". Adv Nutr. 9 (6): 701–716. doi:10.1093/advances/nmy040. PMC   6247336 . PMID   30239557.
  37. ↑ Di Carlo E, Augustin AJ (July 2021). "Prevention of the Onset of Age-Related Macular Degeneration". J Clin Med. 10 (15): 3297. doi: 10.3390/jcm10153297 . PMC   8348883 . PMID   34362080.
  38. 1 2 Gorusupudi A, Nelson K, Bernstein PS (January 2017). "The Age-Related Eye Disease 2 Study: Micronutrients in the Treatment of Macular Degeneration". Adv Nutr. 8 (1): 40–53. doi:10.3945/an.116.013177. PMC   5227975 . PMID   28096126.
  39. ↑ Evans JR, Lawrenson JG (July 2017). "Antioxidant vitamin and mineral supplements for preventing age-related macular degeneration". Cochrane Database Syst Rev. 2017 (7): CD000253. doi:10.1002/14651858.CD000253.pub4. PMC   6483250 . PMID   28756617.
  40. ↑ Druesne-Pecollo N, Latino-Martel P, Norat T, Barrandon E, Bertrais S, Galan P, et al. (July 2010). "Beta-carotene supplementation and cancer risk: a systematic review and metaanalysis of randomized controlled trials". International Journal of Cancer. 127 (1): 172–84. doi: 10.1002/ijc.25008 . PMID   19876916. S2CID   24850769.
  41. ↑ Misotti AM, Gnagnarella P (October 2013). "Vitamin supplement consumption and breast cancer risk: a review". ecancermedicalscience. 7: 365. doi:10.3332/ecancer.2013.365. PMC   3805144 . PMID   24171049.
  42. ↑ Russell RM (January 2004). "The enigma of beta-carotene in carcinogenesis: what can be learned from animal studies". The Journal of Nutrition. 134 (1): 262S–268S. doi: 10.1093/jn/134.1.262S . PMID   14704331.
  43. ↑ Zhang LR, Sawka AM, Adams L, Hatfield N, Hung RJ (March 2013). "Vitamin and mineral supplements and thyroid cancer: a systematic review". European Journal of Cancer Prevention. 22 (2): 158–68. doi:10.1097/cej.0b013e32835849b0. PMID   22926510. S2CID   35660646.
  44. ↑ Mathew MC, Ervin AM, Tao J, Davis RM (June 2012). "Antioxidant vitamin supplementation for preventing and slowing the progression of age-related cataract". The Cochrane Database of Systematic Reviews. 6 (6): CD004567. doi:10.1002/14651858.CD004567.pub2. PMC   4410744 . PMID   22696344.
  45. ↑ Cui YH, Jing CX, Pan HW (September 2013). "Association of blood antioxidants and vitamins with risk of age-related cataract: a meta-analysis of observational studies". The American Journal of Clinical Nutrition. 98 (3): 778–86. doi: 10.3945/ajcn.112.053835 . PMID   23842458.
  46. ↑ Song J, Wang X, Li D, Liu C (18 December 2017). "Degradation kinetics of carotenoids and visual colour in pumpkin (Cucurbita maxima L.) slices during microwave-vacuum drying". International Journal of Food Properties. 20 (sup1): S632–S643. doi: 10.1080/10942912.2017.1306553 . ISSN   1094-2912. S2CID   90336692.
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