Lycopene Treatment of Prostate Cancer Cell Lines Inhibits Adhesion
Lycopene kháng PC3
From Wikipedia, the free encyclopedia
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| Names | |
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| 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
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| Other names
ψ,ψ-Carotene
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| Identifiers | |
3D model (JSmol)
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.007.227 |
| EC Number | 207-949-1 |
| E number | E160d (colours) |
PubChem CID
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| 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 | |
| Flash point | 350.7 °C (663.3 °F; 623.8 K) [1] |
| Supplementary data page | |
| Refractive index (n), Dielectric constant (εr), 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).
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| Infobox references | |
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 Aactivity.[3] Foods that are not red may also contain lycopene, such as asparagus and parsley.[2]
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 bondsgive 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
[hide]Consumption by humans[edit]
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]
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Structure and physical properties[edit]
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]
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]
Biosynthesis[edit]
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 removal[edit]
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 sources[edit]
| 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]
Metabolism[edit]
| 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 effects[edit]
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 effects[edit]
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 States[edit]
In a review of literature on lycopene and its potential role as a dietary antioxidant, the European Food Safety Authorityconcluded 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."
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