Open main menu

Wikipedia β

Lycopene from the neo-Latin lycopersicum, the tomato species, is a bright red carotene and carotenoid pigment and phytochemical found in tomatoes and other red fruits and vegetables, such as red carrots, watermelons, gac, and papayas, although not in strawberries, or cherries.[2] Although lycopene is chemically a carotene, it has no vitamin A activity.[3] Foods that are not red may also contain lycopene, such as asparagus and parsley.[2]

Lycopene
Lycopene powder.jpg
Lycopene3D.png
Names
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
Other names
ψ,ψ-Carotene
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.007.227
EC Number 207-949-1
E number E160d (colours)
UNII
Properties
C40H56
Molar mass 536.89 g·mol−1
Appearance deep red solid
Density 0.889 g/cm3
Melting point 172–173 °C (342–343 °F; 445–446 K)
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
Main hazards Combustible
Safety data sheet See: data page
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oilHealth code 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g., sodium chlorideReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
Flash point 350.7 °C (663.3 °F; 623.8 K) [1]
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Thermodynamic
data
Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
Infobox references

In plants, algae, and other photosynthetic organisms, lycopene is an important intermediate in the biosynthesis of many carotenoids, including beta carotene, which is responsible for yellow, orange, or red pigmentation, photosynthesis, and photoprotection.[3] Like all carotenoids, lycopene is a polyunsaturated hydrocarbon, i.e. an unsubstituted alkene. Structurally, lycopene is a tetraterpene and assembled from eight isoprene units that are composed entirely of carbon and hydrogen.[3] It is insoluble in water. Lycopene's eleven conjugated double bonds give its deep red color and its antioxidant activity in vitro. Owing to the strong color, lycopene is a useful food coloring (registered as E160d) and is approved for usage in the USA,[4] Australia and New Zealand (registered as 160d)[5] and the EU.[6]

Contents

Consumption by humansEdit

Absorption of lycopene requires that it be combined with bile salts and fat to form micelles.[3] Intestinal absorption of lycopene is enhanced by the presence of fat and by cooking.[3] Lycopene dietary supplements (in oil) may be more efficiently absorbed than lycopene from food.[3]

Lycopene is not an essential nutrient for humans, but is commonly found in the diet mainly from dishes prepared from tomatoes.[2][3]

 
Skeletal formula of all-trans lycopene
 
Ball-and-stick model of all-trans lycopene

Structure and physical propertiesEdit

Lycopene is a symmetrical tetraterpene assembled from eight isoprene units. It is a member of the carotenoid family of compounds, and because it consists entirely of carbon and hydrogen, is also a carotene.[3] 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 straight, constrained by its system of eleven conjugated double bonds. Each extension in this conjugated system reduces the energy required for electrons to transition to higher energy states, allowing the molecule to absorb visible light of progressively longer wavelengths. Lycopene absorbs all but the longest wavelengths of visible light, so it appears red.[3]

Plants and photosynthetic bacteria naturally produce all-trans lycopene.[3] When exposed to light or heat, lycopene can undergo isomerization to any of a number of cis-isomers, which have a bent rather than linear shape. Different isomers were shown to have different stabilities due to their molecular energy (highest stability: 5-cis ≥ all-trans ≥ 9-cis ≥ 13-cis > 15-cis > 7-cis > 11-cis: lowest).[7] In the human bloodstream, various cis-isomers constitute more than 60% of the total lycopene concentration, but the biological effects of individual isomers have not been investigated.[8]

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

Carotenoids like lycopene are important pigments found in photosynthetic pigment-protein complexes in plants, photosynthetic bacteria, fungi, and algae.[3] 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 many important carotenoids, such as beta-carotene, and xanthophylls.[9]

BiosynthesisEdit

The unconditioned biosynthesis of lycopene in eukaryotic plants and in prokaryotic cyanobacteria is similar, as are the enzymes involved.[3] 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 twenty-carbon geranylgeranyl pyrophosphate. Two molecules of this product are then condensed in a tail-to-tail configuration to give the forty-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.[3]

Staining and removalEdit

Lycopene is the pigment in tomato-containing sauces, turning plastic cookware orange and is insoluble in water. It can be dissolved only 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 can be soaked in a solution containing a small amount of household bleach.[10]

Dietary sourcesEdit

Dietary sources of lycopene[3]
Source mg wet weight
Gac 2,000–2,300
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

Fruits and vegetables that are high in lycopene include autumn olive, gac, tomatoes, watermelon, pink grapefruit, pink guava, papaya, seabuckthorn, wolfberry (goji, a berry relative of tomato), and rosehip.[3] Ketchup is a common dietary source of lycopene.[3] Although gac (Momordica cochinchinensis Spreng) has the highest content of lycopene of any known fruit or vegetable (multiple times more than tomatoes),[11][12] tomatoes and tomato-based sauces, juices, and ketchup account for more than 85% of the dietary intake of lycopene for most people.[3] The lycopene content of tomatoes depends on species and increases as the fruit ripens.[13]

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.[3][14] Lycopene in tomato paste is up to four times more bioavailable than in fresh tomatoes.[15]

While most green leafy vegetables and other sources of lycopene are low in fats and oils, lycopene is insoluble in water and is tightly bound to vegetable fiber. Processed tomato products such as pasteurized tomato juice, soup, sauce, and ketchup contain the highest concentrations of bioavailable lycopene from tomato-based sources.[3][16]

Cooking and crushing tomatoes (as in the canning process) and serving in oil-rich dishes (such as spaghetti sauce or pizza) greatly increases assimilation from the digestive tract into the bloodstream. Lycopene is fat-soluble, so the oil is said to help absorption.

Lycopene may be obtained from vegetables and fruits such as the tomato, but another source of lycopene is the fungus Blakeslea trispora. Gac is a possible commercial source of lycopene for the purposes of extraction and purification, as its seed content of lycopene is high.[17]

Note that there are some resources which make the mistaken assumption that all red fruits contain lycopene, when in fact many are pigmented by other chemicals. An example is the blood orange, which is colored by anthocyanins,[18] while other red colored oranges, such as the Cara cara navel, and other citrus fruit, such as pink grapefruit, are colored by lycopene.[2][19]

In addition, some foods that do not appear red also contain lycopene, e.g., asparagus, which contains approximately 30μg of lycopene per 100 gram serving[2] (0.3μg/g) and dried parsley and basil, which contain approximately 3.5-7 μg of lycopene per gram.[2]

MetabolismEdit

Distribution of lycopene[citation needed]
Tissue nmol/g wet weight
Liver 1.28–5.72
Kidney 0.15–0.62
Adrenal 1.9–21.6
Testes 4.34–21.4
Ovary 0.25–0.28
Adipose 0.2–1.3
Lung 0.22–0.57
Colon 0.31
Breast 0.78
Skin 0.42

Adverse effectsEdit

 
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.[20]

Lycopene may increase the risk of bleeding when taken with anticoagulant drugs.[20] 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.[20]

Research and potential health effectsEdit

Lycopene is under a variety of basic and clinical research, including primarily its potential effects on cardiovascular diseases and prostate cancer.[21][22][23]

Regulatory status in Europe and the United StatesEdit

In a review of literature on lycopene and its potential role as a dietary antioxidant, the European Food Safety Authority concluded that there was insufficient evidence for lycopene having this effect in humans, particularly as it may affect skin, heart function or vision protection from ultraviolet light.[24]

Lycopene from tomatoes has been tested in human studies in the United States and other countries for cardiovascular diseases and prostate cancer. These studies, however, did not attain sufficient scientific agreement to conclude an effect on any disease.[25] The US Food and Drug Administration (FDA), in rejecting manufacturers' requests in 2005 to allow "qualified labeling" for lycopene and the reduction of various cancer risks, provided a conclusion remaining in effect in 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 alsoEdit

ReferencesEdit

  1. ^ a b c d e "Lycopene". PubChem, US National Library of Medicine. 2016. Retrieved 13 October 2016. 
  2. ^ a b c d e f "Foods highest in lycopene, Nutrition Data, USDA Nutrient Database, version SR-21". nutritiondata.com. Conde Nast. 2014. Retrieved 2014-08-19. 
  3. ^ 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. Retrieved 29 May 2017. 
  4. ^ "21 CFR 73.585. Tomato lycopene extract" (PDF). US Food and Drug Administration. 26 July 2005. 
  5. ^ Australia New Zealand Food Standards Code"Standard 1.2.4 - Labelling of ingredients". Retrieved 2011-10-27. 
  6. ^ UK Food Standards Agency: "Current EU approved additives and their E Numbers". Retrieved 2011-10-27. 
  7. ^ Chasse et al. Journal of Molecular Structure: THEOCHEM, Volume 571, Number 1, 27 August 2001 , pp. 27-37(11)[1]
  8. ^ Erdman Jr, J. W. (2005). "How do nutritional and hormonal status modify the bioavailability, uptake, and distribution of different isomers of lycopene?". The Journal of nutrition. 135 (8): 2046S–7S. PMID 16046737. 
  9. ^ NDSU Agriculture. "What Color is Your Food?". Retrieved 10 May 2012. 
  10. ^ Barnes, Chris (11 October 2011). "How To Clean Tomato Sauce Stains From Plastic Storage Containers". The Huffington Post. Retrieved 29 May 2017. 
  11. ^ Tran, X. T.; Parks, S. E.; Roach, P. D.; Golding, J. B.; Nguyen, M. H. (2015). "Effects of maturity on physicochemical properties of Gac fruit (Momordica cochinchinensis Spreng.)". Food Science & Nutrition. 4 (2): 305–314. PMC 4779482 . doi:10.1002/fsn3.291. 
  12. ^ Ishida BK, Turner C, Chapman MH, McKeon TA (January 2004). "Fatty acid and carotenoid composition of gac (Momordica cochinchinensis Spreng) fruit". Journal of Agricultural and Food Chemistry. 52 (2): 274–9. PMID 14733508. doi:10.1021/jf030616i. 
  13. ^ Ilahy, R; Piro, G; Tlili, I; Riahi, A; Sihem, R; Ouerghi, I; Hdider, C; Lenucci, M. S. (2016). "Fractionate analysis of the phytochemical composition and antioxidant activities in advanced breeding lines of high-lycopene tomatoes". Food Funct. 7 (1): 574–83. PMID 26462607. doi:10.1039/c5fo00553a. 
  14. ^ Perdomo F, Cabrera Fránquiz F, Cabrera J, Serra-Majem L (2012). "Influence of cooking procedure on the bioavailability of lycopene in tomatoes". Hospital Nutrition (Madrid). 27 (5): 1542–6. PMID 23478703. doi:10.3305/nh.2012.27.5.5908 (inactive 2017-05-29). 
  15. ^ Kamiloglu, S.; Demirci, M.; Selen, S.; Toydemir, G.; Boyacioglu, D.; Capanoglu, E. (2014). "Home processing of tomatoes (Solanum lycopersicum): Effects onin vitrobioaccessibility of total lycopene, phenolics, flavonoids, and antioxidant capacity". Journal of the Science of Food and Agriculture. 94 (11): 2225–33. PMID 24375495. doi:10.1002/jsfa.6546. 
  16. ^ Yamaguchi, Masayoshi (2010). Carotenoids : Properties, Effects and Diseases. New York: Nova Science Publishers. p. 125. ISBN 9781612097138. 
  17. ^ Aoki, H; Kieu, N. T.; Kuze, N; Tomisaka, K; Van Chuyen, N (2002). "Carotenoid pigments in GAC fruit (Momordica cochinchinensis SPRENG)". Bioscience, Biotechnology and Biochemistry. 66 (11): 2479–82. PMID 12506992. doi:10.1271/bbb.66.2479. 
  18. ^ Hillebrand, S; Schwarz, M; Winterhalter, P (2004). "Characterization of anthocyanins and pyranoanthocyanins from blood orange Citrus sinensis (L.) Osbeck juice". Journal of Agricultural and Food Chemistry. 52 (24): 7331–8. PMID 15563216. doi:10.1021/jf0487957. 
  19. ^ Alquezar, B; Rodrigo, M. J.; Zacarías, L (2008). "Regulation of carotenoid biosynthesis during fruit maturation in the red-fleshed orange mutant Cara Cara". Phytochemistry. 69 (10): 1997–2007. PMID 18538806. doi:10.1016/j.phytochem.2008.04.020. 
  20. ^ a b c "Lycopene". Mayo Clinic. 2017. Retrieved 29 May 2017. 
  21. ^ Cheng, H. M.; Koutsidis, G; Lodge, J. K.; Ashor, A; Siervo, M; Lara, J (2017). "Tomato and lycopene supplementation and cardiovascular risk factors: A systematic review and meta-analysis". Atherosclerosis. 257: 100–108. PMID 28129549. doi:10.1016/j.atherosclerosis.2017.01.009. 
  22. ^ Ilic, D.; Forbes, KM.; Hassed, C. (2011). "Lycopene for the prevention of prostate cancer". Cochrane Database Syst Rev (11): CD008007. PMID 22071840. doi:10.1002/14651858.CD008007.pub2. 
  23. ^ Rowles Jl, 3rd; Ranard, K. M.; Smith, J. W.; An, R; Erdman Jr, J. W. (2017). "Increased dietary and circulating lycopene are associated with reduced prostate cancer risk: A systematic review and meta-analysis". Prostate Cancer and Prostatic Diseases. PMID 28440323. doi:10.1038/pcan.2017.25. 
  24. ^ "Scientific Opinion on the substantiation of health claims related to lycopene and protection of DNA, proteins and lipids from oxidative damage (ID 1608, 1609, 1611, 1662, 1663, 1664, 1899, 1942, 2081, 2082, 2142, 2374), protection of the skin from UV-induced (including photo-oxidative) damage (ID 1259, 1607, 1665, 2143, 2262, 2373), contribution to normal cardiac function (ID 1610, 2372), and maintenance of normal vision (ID 1827) pursuant to Article 13(1) of Regulation (EC) No 1924/2006". EFSA Journal. 9 (4). 2011. doi:10.2903/j.efsa.2011.2031/epdf (inactive 2017-05-29). 
  25. ^ "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. 

External linksEdit