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| Names | |
|---|---|
| IUPAC name ψ,ψ-Carotene | |
| Systematic IUPAC name (6E,8E,10E,12E,14E,16E,18E,20E,22E,24E,26E)-2,6,10,14,19,23,27,31-Octamethyldotriaconta-2,6,8,10,12,14,16,18,20,22,24,26,30-tridecaene | |
| Identifiers | |
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3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
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| ECHA InfoCard | 100.007.227 |
| EC Number |
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| E number | E160d(colours) |
| UNII | |
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| Properties | |
| C40H56 | |
| Molar mass | 536.888 g·mol−1 |
| Appearance | deep red solid |
| Density | 0.889 g/cm3 |
| Melting point | 177 °C (351 °F; 450 K)[2] |
| Boiling point | 660.9 °C (1,221.6 °F; 934.0 K) at 760 mmHg[1] |
| insoluble | |
| Solubility | soluble inCS2,CHCl3,THF,ether,C6H14,vegetable oil insoluble inCH3OH,C2H5OH[1] |
| Solubility inhexane | 1 g/L (14 °C)[1] |
| Vapor pressure | 1.33·10−16 mmHg (25 °C)[1] |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards | Combustible |
| NFPA 704 (fire diamond) | |
| Flash point | 350.7 °C (663.3 °F; 623.8 K)[1] |
| Supplementary data page | |
| Lycopene (data page) | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Lycopene is anorganic compound classified as atetraterpene and acarotene.[3] Lycopene (from theNeo-LatinLycopersicon, the name of a former tomato genus) is a bright redcarotenoidhydrocarbon found intomatoes and other red fruits and vegetables.
Aside from tomatoes or tomato products likeketchup, it is found inwatermelons,grapefruits, redguavas, andbaked beans.[4] It has novitamin A activity.[4]
Inplants,algae, and otherphotosynthetic organisms, lycopene is an intermediate in the biosynthesis of many carotenoids, includingbeta-carotene, which is responsible for yellow, orange, or red pigmentation,photosynthesis, andphotoprotection.[4]
Like all carotenoids, lycopene is atetraterpene.[4] It is soluble infat, but insoluble in water.[4] Elevenconjugated double bonds give lycopene its deep red color.[4]
Owing to the strong color, lycopene is used as afood coloring (registered as E160d) and is approved for use in the US,[5] Australia and New Zealand (registered as 160d),[6] and theEuropean Union (E160d).[7]
Lycopene is a symmetricaltetraterpene because it consists entirely of carbon and hydrogen and is derived from eightisoprene subunits.[4] Isolation procedures for lycopene were first reported in 1910, and the structure of the molecule was determined by 1931. In its natural, all-trans form, the molecule is long and somewhat flat, constrained by its system of 11 conjugated double bonds. The extended conjugation is responsible for its deep red color.[4]
Plants and photosynthetic bacteria produce all-trans lycopene.[4] When exposed to light or heat, lycopene can undergoisomerization to any of a number ofcis-isomers, which have a less linear shape. Isomers distinct stabilities, with highest stability: 5-cis ≥ all-trans ≥ 9-cis ≥ 13-cis > 15-cis > 7-cis > 11-cis: lowest.[8][9] In human blood, variouscis-isomers constitute more than 60% of the total lycopene concentration, but the biological effects of individual isomers have not been investigated.[10]
Carotenoids like lycopene are found inphotosynthetic pigment-protein complexes in plants, photosynthetic bacteria, fungi, and algae.[4] They are responsible for the bright orange–red colors of fruits and vegetables, perform various functions in photosynthesis, and protect photosynthetic organisms from excessive light damage. Lycopene is a key intermediate in the biosynthesis of carotenoids, such asbeta-carotene, andxanthophylls.[11]
Dispersed lycopene molecules can be encapsulated intocarbon nanotubes enhancing theiroptical properties.[12] Efficient energy transfer occurs between the encapsulated dye and nanotube—light is absorbed by the dye and without significant loss is transferred to the nanotube. Encapsulation increases chemical and thermal stability of lycopene molecules; it also allows their isolation and individual characterization.[13]
The unconditioned biosynthesis of lycopene in eukaryotic plants and in prokaryotic cyanobacteria is similar, as are the enzymes involved.[4] Synthesis begins withmevalonic acid, which is converted intodimethylallyl pyrophosphate. This is then condensed with three molecules ofisopentenyl pyrophosphate (an isomer of dimethylallyl pyrophosphate), to give the 20-carbongeranylgeranyl pyrophosphate. Two molecules of this product are then condensed in a tail-to-tail configuration to give the 40-carbonphytoene, the first committed step in carotenoid biosynthesis. Through several desaturation steps, phytoene is converted into lycopene. The two terminal isoprene groups of lycopene can be cyclized to produce beta-carotene, which can then be transformed into a wide variety of xanthophylls.[4]
Lycopene is thepigment in tomato sauces that turns plastic cookware orange. It is insoluble in plain water, but it can be dissolved in organic solvents and oils. Because of its non-polarity, lycopene in food preparations will stain any sufficientlyporous material, including most plastics. To remove this staining, the plastics may be soaked in a solution containing a small amount of chlorine bleach.[14]The bleach oxidizes the lycopene, thus rendering it colourless.
Absorption of lycopene requires that it be combined withbile salts and fat to formmicelles.[4] Intestinal absorption of lycopene is enhanced by the presence of fat and by cooking.[4] Lycopenedietary supplements (in oil) may be more efficiently absorbed than lycopene from food.[4]
Lycopene is not anessential nutrient for humans, but is commonly found in the diet mainly from dishes prepared from tomatoes.[4] The median and 99th percentile of dietary lycopene intake have been estimated to be 5.2 and 123 mg/d, respectively.[15]
| Source | mg wet weight |
|---|---|
| Gac aril | 2~6 per gram[16][17] |
| Rawtomato | 4.6 percup |
| Tomato juice | 22 per cup |
| Tomato paste | 75 per cup |
| Tomatoketchup | 2.5 pertablespoon |
| Watermelon | 13 per wedge |
| Pink grapefruit | 2 per half grapefruit |
Fruits andvegetables that are high in lycopene includeautumn olive,gac, tomatoes,watermelon, pinkgrapefruit, pinkguava,papaya,seabuckthorn,wolfberry (goji, a berry relative of tomato), androsehip.[4]Ketchup is a common dietary source of lycopene.[4] Althoughgac (Momordica cochinchinensis Spreng) has the highest content of lycopene of any known fruit or vegetable (multiple times more than tomatoes),[18][19] tomatoes and tomato-based sauces, juices, and ketchup account for more than 85% of the dietary intake of lycopene for most people.[4] The lycopene content of tomatoes depends on variety and increases as the fruit ripens.[20]
Unlike other fruits and vegetables, where nutritional content such asvitamin C is diminished upon cooking,processing of tomatoes increases the concentration ofbioavailable lycopene.[4][21] Lycopene in tomato paste is up to four times more bioavailable than in fresh tomatoes.[22] Processed tomato products such as pasteurized tomato juice, soup, sauce, and ketchup contain a higher concentration of bioavailable lycopene compared to raw tomatoes.[4][23]
Cooking and crushing tomatoes (as in thecanning process) and serving in oil-rich dishes (such asspaghetti sauce orpizza) greatly increases assimilation from the digestive tract into the bloodstream. Lycopene is fat-soluble, so the oil is said to help absorption. Gac has high lycopene content derived mainly from itsseed coats.[24]Cara Cara navel oranges, and other citrus fruit, such aspink grapefruits, also contain lycopene.[4][25] Some foods that do not appear red also contain lycopene, e.g., baked beans.[4] When lycopene is used as a food additive (E160d), it is usually obtained from tomatoes.[4][26]
Lycopene is non-toxic and commonly found in the diet, mainly from tomato products.[4] There are cases of intolerance or allergic reaction to dietary lycopene, which may causediarrhea,nausea, stomach pain or cramps, gas, and loss of appetite.[27] Lycopene may increase the risk of bleeding when taken withanticoagulant drugs.[27] Because lycopene may cause low blood pressure, interactions with drugs that affect blood pressure may occur. Lycopene may affect theimmune system, thenervous system, sensitivity to sunlight, or drugs used for stomach ailments.[27]
Lycopenemia is an orange discoloration of the skin that is observed with high intakes of lycopene.[15] The discoloration is expected to fade after discontinuing excessive lycopene intake.[15]
A 2020 review ofrandomized controlled trials found conflicting evidence for lycopene having an effect oncardiovascularrisk factors,[28] whereas a 2017 review concluded that tomato products and lycopene supplementation reducedblood lipids andblood pressure.[29]
A 2015 review found that dietary lycopene was associated with reduced risk ofprostate cancer,[30] whereas a 2021meta-analysis found that dietary lycopene did not affect prostate cancer risk.[31] Other reviews concluded that research has been insufficient to establish whether lycopene consumption affects human health.[32]
In a review of literature on lycopene and its potential benefit in the diet, theEuropean Food Safety Authority concluded there was insufficient evidence for lycopene having antioxidant effects in humans, particularly in skin, heart function, or vision protection fromultraviolet light.[33]
Although lycopene from tomatoes has been tested in humans for cardiovascular diseases and prostate cancer, no effect on any disease was found.[34] The USFood and Drug Administration, in rejecting manufacturers' requests in 2005 to allow "qualified labeling" for lycopene and the reduction of various cancer risks, provided a conclusion that remains in effect as of 2015[update]:
no studies provided information about whether lycopene intake may reduce the risk of any of the specific forms of cancer. Based on the above, FDA concludes that there is no credible evidence supporting a relationship between lycopene consumption, either as a food ingredient, a component of food, or as a dietary supplement, and any of these cancers.[34]
In a review of research through 2024, the USNational Cancer Institute concluded that the FDA has not approved the use of lycopene as effective for treating any medical condition, including various types of cancer.[35]
Lycopenemia, characterized by an orange discoloration of the skin, has been observed with high intakes of lycopene-containing foods. One case study reported the incidence of lycopenemia in a 61-y-old woman who had consumed ~2 L of tomato juice daily for several years (10). Although there was evidence of lycopene and fatty deposits in the liver, there was an absence of measurable hepatic dysfunction. After 3 wk of consuming a diet free of tomato juice, the orange discoloration faded.
