Lycopene

Source: Wikipedia, the free encyclopedia.
Lycopene
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
3D model (
JSmol
)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard
 100.007.227 Edit this at Wikidata
EC Number
  • 207-949-1
E number E160d (colours)
UNII
  • InChI=1S/C40H56/c1-33(2)19-13-23-37(7)27-17-31-39(9)29-15-25-35(5)21-11-12-22-36(6)26-16-30-40(10)32-18-28-38(8)24-14-20-34(3)4/h11-12,15-22,25-32H,13-14,23-24H2,1-10H3/b12-11+,25-15+,26-16+,31-17+,32-18+,35-21+,36-22+,37-27+,38-28+,39-29+,40-30+ checkY
    Key: OAIJSZIZWZSQBC-GYZMGTAESA-N checkY
  • InChI=1/C40H56/c1-33(2)19-13-23-37(7)27-17-31-39(9)29-15-25-35(5)21-11-12-22-36(6)26-16-30-40(10)32-18-28-38(8)24-14-20-34(3)4/h11-12,15-22,25-32H,13-14,23-24H2,1-10H3/b12-11+,25-15+,26-16+,31-17+,32-18+,35-21+,36-22+,37-27+,38-28+,39-29+,40-30+
    Key: OAIJSZIZWZSQBC-GYZMGTAEBZ
  • C(\C=C\C=C(\CC/C=C(\C)C)C)(=C/C=C/C(=C/C=C/C=C(/C=C/C=C(/C=C/C=C(\C)CC\C=C(/C)C)C)C)C)C
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 in CS2, CHCl3, THF, ether, C6H14, vegetable oil
insoluble in CH3OH, C2H5OH[1]
Solubility in hexane 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)
NFPA 704 four-colored diamondHealth 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 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 their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Lycopene is an organic compound classified as a tetraterpene and a carotene.[3] Lycopene (from the Neo-Latin Lycopersicon, the name of a former tomato genus) is a bright red carotenoid hydrocarbon found in tomatoes and other red fruits and vegetables.

Occurrence

Aside from tomatoes, it is found in red carrots, watermelons, grapefruits, and papayas. It is not present in strawberries or cherries.[4] It has no vitamin A activity.[5]

In

beta-carotene, which is responsible for yellow, orange, or red pigmentation, photosynthesis, and photoprotection.[5] Like all carotenoids, lycopene is a tetraterpene.[5] It is insoluble in water. Eleven conjugated double bonds give lycopene its deep red color. Owing to the strong color, lycopene is useful as a food coloring (registered as E160d) and is approved for use in the US,[6] Australia and New Zealand (registered as 160d)[7] and the European Union.[8]

Structure and physical properties

Lycopene is a symmetrical tetraterpene because it consists entirely of carbon and hydrogen and is derived from eight isoprene subunits.[5] 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.[5]

Plants and photosynthetic bacteria produce all-trans lycopene.[5] When exposed to light or heat, lycopene can undergo isomerization to any of a number of cis-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.[9][10] In human blood, various cis-isomers constitute more than 60% of the total lycopene concentration, but the biological effects of individual isomers have not been investigated.[11]

Lycopene is a key intermediate in the biosynthesis of many carotenoids.

Carotenoids like lycopene are found in

beta-carotene, and xanthophylls.[12]

Dispersed lycopene molecules can be encapsulated into carbon nanotubes enhancing their optical properties.[13] 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.[14]

Biosynthesis

The unconditioned biosynthesis of lycopene in eukaryotic plants and in prokaryotic cyanobacteria is similar, as are the enzymes involved.[5] Synthesis begins with mevalonic acid, which is converted into dimethylallyl pyrophosphate. This is then condensed with three molecules of isopentenyl pyrophosphate (an isomer of dimethylallyl pyrophosphate), to give the 20-carbon geranylgeranyl pyrophosphate. Two molecules of this product are then condensed in a tail-to-tail configuration to give the 40-carbon phytoene, 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.[5]

Staining and removal

Lycopene is the pigment 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 sufficiently porous material, including most plastics. To remove this staining, the plastics may be soaked in a solution containing a small amount of chlorine bleach.[15] The bleach oxidizes the lycopene, thus allowing the product to dissolve.

Diet

Consumption by humans

Absorption of lycopene requires that it be combined with

bile salts and fat to form micelles.[5] Intestinal absorption of lycopene is enhanced by the presence of fat and by cooking.[5] Lycopene dietary supplements (in oil) may be more efficiently absorbed than lycopene from food.[5]

Lycopene is not an

essential nutrient for humans, but is commonly found in the diet mainly from dishes prepared from tomatoes.[4][5] The median and 99th percentile of dietary lycopene intake have been estimated to be 5.2 and 123 mg/d, respectively.[16]

Sources

Dietary sources of lycopene[5]
Source mg wet weight
Gac aril 2~6 per gram[17][18]
Raw tomato 4.6 per cup
Tomato juice 22 per cup
Tomato paste 75 per cup
Tomato ketchup 2.5 per tablespoon
Watermelon 13 per wedge
Pink grapefruit
 2 per half grapefruit

rosehip.[5] Ketchup is a common dietary source of lycopene.[5] Although gac (Momordica cochinchinensis Spreng) has the highest content of lycopene of any known fruit or vegetable (multiple times more than tomatoes),[19][20] tomatoes and tomato-based sauces, juices, and ketchup account for more than 85% of the dietary intake of lycopene for most people.[5] The lycopene content of tomatoes depends on variety and increases as the fruit ripens.[21]

Unlike other fruits and vegetables, where nutritional content such as vitamin C is diminished upon cooking, processing of tomatoes increases the concentration of bioavailable lycopene.[5][22] Lycopene in tomato paste is up to four times more bioavailable than in fresh tomatoes.[23] Processed tomato products such as pasteurized tomato juice, soup, sauce, and ketchup contain a higher concentration of bioavailable lycopene compared to raw tomatoes.[5][24]

Cooking and crushing tomatoes (as in the

pink grapefruit, also contain lycopene.[4][26] Some foods that do not appear red also contain lycopene, e.g., asparagus, which contains about 30 μg of lycopene per 100-g serving[4] (0.3 μg/g) and dried parsley and basil, which contain around 3.5–7.0 μg/g of lycopene.[4]
When lycopene is used as a food additive (E160d), it is usually obtained from tomatoes.[27]

Adverse effects

Test tube containing a dichloromethane solution of lycopene

Lycopene is non-toxic and commonly found in the diet, mainly from tomato products. There are cases of intolerance or allergic reaction to dietary lycopene, which may cause diarrhea, nausea, stomach pain or cramps, gas, and loss of appetite.[28] Lycopene may increase the risk of bleeding when taken with anticoagulant drugs.[28] Because lycopene may cause low blood pressure, interactions with drugs that affect blood pressure may occur. Lycopene may affect the immune system, the nervous system, sensitivity to sunlight, or drugs used for stomach ailments.[28]

Lycopenemia is an orange discoloration of the skin that is observed with high intakes of lycopene.[16] The discoloration is expected to fade after discontinuing excessive lycopene intake.[16]

Research and potential health effects

A 2020 review of randomized controlled trials found conflicting evidence for lycopene having an effect on cardiovascular risk factors,[29] whereas a 2017 review concluded that tomato products and lycopene supplementation reduced blood lipids and blood pressure.[30]

A 2015 review found that dietary lycopene was associated with reduced risk of prostate cancer,[31] whereas a 2021 meta-analysis found that dietary lycopene did not affect prostate cancer risk.[32] Other reviews concluded that research has been insufficient to establish whether lycopene consumption affects human health.[33]

Regulatory status in Europe and the United States

In a review of literature on lycopene and its potential benefit in the diet, the

ultraviolet light.[34]

Although lycopene from tomatoes has been tested in humans for cardiovascular diseases and prostate cancer, no effect on any disease was found.[35] The US Food 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 2017:

...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.

See also

References

  1. ^ a b c d e "Lycopene". PubChem, US National Library of Medicine. 2016. Retrieved 13 October 2016.
  2. ISBN 978-1439855119
    .
  3. ISBN 0471238961
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  4. ^ a b c d e "Foods highest in lycopene, Nutrition Data, USDA Nutrient Database, version SR-21". nutritiondata.com. Conde Nast. 2014. Retrieved 2014-08-19.
  5. ^ a b c d e f g h i j k l m n o p q r s "Carotenoids: α-Carotene, β-Carotene, β-Cryptoxanthin, Lycopene, Lutein, and Zeaxanthin". Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis, OR. July 2016. Archived from the original on 21 May 2017. Retrieved 29 May 2017.
  6. ^ "21 CFR 73.585. Tomato lycopene extract" (PDF). US Food and Drug Administration. 26 July 2005.
  7. ^ Australia New Zealand Food Standards Code"Standard 1.2.4 – Labelling of ingredients". Retrieved 2011-10-27.
  8. ^ UK Food Standards Agency: "Current EU approved additives and their E Numbers". Retrieved 2011-10-27.
  9. doi:10.1016/S0166-1280(01)00424-9
    .
  10. doi:10.1016/S0166-1280(01)00413-4
    .
  11. PMID 16046737
    .
  12. ^ NDSU Agriculture. "What Color is Your Food?". Retrieved 10 May 2012.
  13. doi:10.1103/PhysRevB.74.155420. Archived from the original
    (PDF) on 2020-10-02. Retrieved 2019-02-12.
  14. ^ Saito, Yuika; Yanagi, Kazuhiro; Hayazawa, Norihiko; Ishitobi, Hidekazu; Ono, Atsushi; Kataura, Hiromichi; Kawata, Satoshi (2006). "Vibrational Analysis of Organic Molecules Encapsulated in Carbon Nanotubes by Tip-Enhanced Raman Spectroscopy". Jpn. J. Appl. Phys. 45 (12): 9286–9289.
    S2CID 122152101
    .
  15. ^ Barnes, Chris (11 October 2011). "How To Clean Tomato Sauce Stains From Plastic Storage Containers". The Huffington Post. Retrieved 29 May 2017.
  16. ^
    PMID 16046742
    . 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.
  17. PMID 14733508
    .
  18. ^ "Gac (Momordica cochinchinensis) Analysis report" (PDF). Archived from the original (PDF) on 2018-04-13. Retrieved 2018-04-13.
  19. PMID 27004120
    .
  20. PMID 14733508
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  21. PMID 26462607
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  22. PMID 23478703
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  23. PMID 24375495
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  24. ISBN 9781612097138
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  25. S2CID 2118248
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  26. PMID 18538806
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  27. S2CID 225058089
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  28. ^ a b c "Lycopene". Mayo Clinic. 2017. Archived from the original on 23 September 2017. Retrieved 29 May 2017.
  29. PMID 32652029
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  30. S2CID 19287598
    .
  31. PMID 26287411
    .
  32. PMID 34017849
    .
  33. PMID 22129335
    .
  34. doi:10.2903/j.efsa.2011.2031
    .
  35. ^ "Qualified Health Claims: Letter Regarding Tomatoes and Prostate Cancer (Lycopene Health Claim Coalition) (Docket No. 2004Q-0201)". US Food and Drug Administration. 8 November 2005. Archived from the original on 22 July 2017. Retrieved 16 December 2019.
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