Dictionary:
ly·co·pene (lī'kə-pēn')  |
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| Food and Nutrition: lycopene |
Red carotenoid pigment found in tomato, pink grapefruit, and palm oil. Not vitamin A active, but an antioxidant; also used as a food colour.
| Alternative Medicine Encyclopedia: Lycopene |
Description
Lycopene is a red, fat-soluble pigment found in vegetables, and most commonly found in tomatoes. It is one of a family of pigments called carotenoids. Carotenoids are naturally occurring pigments responsible for the brightly colored fall leaves and the vivid colors of flowers, fruits, and vegetables. In fruits and vegetables, these pigments range in hue from bright yellow in squash, to orange in carrots, to bright red in tomatoes and peppers.
Although the human body does not produce lycopene, it is readily available through the diet. Minor sources include guava, rosehip, watermelon, and pink grapefruit. However, about 85% of lycopene in the U.S. diet comes from tomatoes and tomato products such as juice, soup, sauce, paste, and ketchup. A diet rich in carotenoid-containing foods is associated with a variety of health benefits.
Once lycopene is absorbed in the body, it is deposited widely in the liver, lungs, prostate gland, colon, and skin. Its concentration in body tissues tends to be higher than most other carotenoids. Working as a powerful antioxidant, lycopene fights free radicals—highly reactive molecules that damage cell membranes, attack DNA, and cause disease. Studies have found that patients with HIV infection, inflammatory diseases, and high cholesterol levels (with and without lipid-lowering treatment) may have depleted lycopene serum (blood) levels. In contrast to other carotenoids, serum levels of lycopene are not usually reduced by smoking or alcohol consumption but rather by increasing age.
General Use
A number of studies have indicated that a lycopenerich diet lowers the risk of certain chronic diseases such as cardiovascular disease, cancer, and age-related macular degeneration.
Cardiovascular Disease
In its role as an antioxidant, lycopene prevents the oxidation of low-density liproprotein (LDH), the "bad" cholesterol that leads to atherosclerosis (hardening of the arteries) and coronary artery disease.
As serum lycopene levels rise, the levels of oxidized lipoprotein, protein, and DNA compounds go down, thus lowering the risk of heart disease. Individuals with high levels of lycopene are half as likely to have a heart attack than those with low levels, according to one study.
Cancer
Researchers have found a strong relationship between lycopene intake and reduced risk of cancers of the prostate and pancreas. In several studies of these cancers, lycopene was the only carotenoid associated with risk reduction. In late 2001, the first clinical intervention trial of prostate cancer patients showed that supplementation with lycopene helped slow growth of prostate cancer. In fact, the spread of prostate cancer was reduced by 73%.
Consuming tomato products twice a week, as opposed to not at all, was associated with a reduced risk of prostate cancer of up to 34%, according to a study conducted by the Dana-Farber Cancer Institute. Of the 46 fruits and vegetables investigated, only tomato products showed a measurable association with reduced risk of prostate cancer. There is also medical evidence to suggest that a high intake of lycopene-rich tomato products is associated with a reduced risk of developing cancers of the lung, breast, cervix, and gastrointestinal tract.
Macular Degeneration
Lycopene (as well as other carotenoids such as lutein and beta-carotene) may also help prevent macular degenerative disease, the leading cause of blindness in people over the age of 65. Lycopene is the only micronutrient whose serum level was shown to be inversely related to the risk of age-related macular degeneration.
In late 2001, a study showed that lycopene may also help relieve exercise-induced asthma symptoms.
Preparations
Although the major sources of lycopene for humans are tomatoes and tomato products, bioavailability from different food items varies considerably. Cooking fresh tomatoes with a source of fat, such as olive oil in spaghetti sauce, enhances the body's absorption of lycopene, since lycopene is fat-soluble. By heating the tomatoes, the bound chemical form of lycopene is converted into a form that is more easily digested. In fact, one study showed that lycopene is absorbed 2.5 times better from tomato paste than from fresh tomatoes.
Although no dietary guidelines have been established, research shows that drinking two cups (about 540 ml) of tomato juice per day provides about 40 mg of lycopene. This is the amount recommended to significantly reduce the oxidation of LDL cholesterol, according to one human dietary intervention study.
The approximate lycopene content of tomatoes and tomato products, based on an analysis by a number of laboratories (mg/100 g wet weight) are listed below.
Although lycopene is available in concentrated capsule form and in combination with other vitamins, such as vitamin E or multivitamin preparations, there is inadequate evidence to conclude that supplements are more beneficial than the lycopene consumed in foods. Since most of the health benefits of lycopene have been ascertained from studies of estimated dietary intake or blood concentrations, as of the year 2000, researchers recommend that individuals consume a diet rich in carotenoids and an array of fruits and vegetables rather than turning to lycopene supplements. The United States Department of Agriculture reported in 2001 that people intake an average of 10.9mg per day.
Precautions
There are no known precautions regarding lycopene itself. However, there are a number of indirect problems that may result from consuming excessive amounts of tomatoes or commercially prepared tomato products.
Although processed tomato products are the richest source of lycopene in the diet, ingesting tomatoes may aggravate certain health conditions. As a member of the nightshade variety of plants—which includes eggplants, potatoes, peppers, paprika, and tobacco—tomatoes have been strongly and consistently linked with certain forms of arthritis, particularly rheumatoid and osteoarthritis.
One theory maintains that the alkaloids (alkaline chemicals) in the nightshades are deposited in the connective tissue, stimulate inflammation, and then inhibit the formation of normal cartilage. As a result, joint cartilage continues to break down and is not replaced by new, healthy cartilage cells.
Another indirect precaution is that processed tomato products usually contain large amounts of sodium, unless the product is labeled low-sodium or salt-free. An excess amount of sodium in the diet can exacerbate high blood pressure.
Side Effects
Although extensive research has not been conducted, there have been no reported side effects or toxicity associated with lycopene intake.
Interactions
Research into the interactions of lycopene with food, drugs, or diseases has not been conducted as of the year 2000.
Resources
Periodicals
Arab, Lenore and Susan Steck. "Lycopene and Cardiovascular Disease." American Journal of Clinical Nutrition (2000 suppl.): 1961S-1695S.
Bauer, Jeff. "A Tomato Antioxidant May Relieve Asthma." RN (October 2001):21.
Broiher, Kitty. "A Tomato a Day May Keep Cancer Away." Food Processing (April 1999): 58.
"Clinical Intervention Trial Finds Benefit of Lycopene." Cancer Weekly (November 27, 2001) :38.
Clinton, Steven K. "Lycopene: Chemistry, Biology, and Implications for Human Disease." Nutrition Reviews (February 1998): 35-51.
Edens, Neile K. "Representative Components of Functional Food Science." Nutrition Today (July 1999): 152.
McCord, Holly. "You say 'tomato' and I Say 'Terrific.'" Prevention (April 1995): 52.
Zoler, Mitchel L. "Lycopene May Reduce Prostate Cancer Tumor Grade." Family Practice News (May 1999): 28.
Organizations
American Heart Association, National Center. 7272 Greenville Avenue, Dallas, TX 75231. http://www.americanheart.org.
National Cancer Institute. Public Inquiries Office. Building 31, Room 10A03, 31 Center Drive, MSC 2580, Bethesda, MD 20892. http://www.nci.nih.gov.
Other
Heinz Institute of Nutritional Sciences. http://www.lycopene.org.
[Article by: Genevieve Slomski; Teresa Norris]
| Wikipedia: Lycopene |
| Lycopene | |
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| IUPAC name |
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| Other names | (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 | |
| CAS number | [] |
| PubChem | |
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| Properties | |
| Molecular formula | C40H56 |
| Molar mass | 536.87 g mol−1 |
| Appearance | Deep red solid |
| Melting point |
172–173 °C |
| Solubility in water | Insoluble |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references |
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Lycopene is a bright red carotenoid pigment and phytochemical found in tomatoes and other red fruits & vegetables, such as red carrots, watermelons and papayas (but not strawberries or cherries).
In plants, algae, and other photosynthetic organisms, lycopene is an important intermediate in the biosynthesis of many carotenoids, including beta carotene, responsible for yellow, orange or red pigmentation, photosynthesis, and photo-protection. Structurally, it is a tetraterpene assembled from eight isoprene units, composed entirely of carbon and hydrogen, and is insoluble in water. Lycopene's eleven conjugated double bonds give it its deep red color and are responsible for its antioxidant activity. Due to its strong color and non-toxicity, lycopene is a useful food coloring.
Lycopene is not an essential nutrient for humans, but is commonly found in the diet, mainly from dishes prepared with tomato sauce. When absorbed from the stomach, lycopene is transported in the blood by various lipoproteins and accumulates in the liver, adrenal glands, and testes.
Because preliminary research has shown an inverse correlation between consumption of tomatoes and cancer risk, lycopene has been considered a potential agent for prevention of some types of cancers, particularly prostate cancer. However, this area of research and the relationship with prostate cancer have been deemed insufficient of evidence for health claim approval by the US Food and Drug Administration (see below under Antioxidant properties and potential health benefits).
Contents |
Lycopene is a symmetrical tetraterpene assembled from 8 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.[1] 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 double bond in this extended π electron 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.[2]
Plants and photosynthetic bacteria naturally produce all-trans lycopene, but a total of 72 geometric isomers of the molecule are sterically possible.[3] When exposed to light or heat, lycopene can undergo isomerization to any of a number of these cis-isomers, which have a bent rather than linear shape. Different isomeres 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).[4] 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.[5]
Lycopene is insoluble in water, and 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. While a tomato stain can be fairly easily removed from fabric (provided the stain is fresh), lycopene diffuses into plastic, making it impossible to remove with hot water or detergent. If lycopene is oxidized (for example, by reacting with bleaches or acids), the double bonds between the carbon atoms will be broken; cleaving the molecule, breaking the conjugated double bond system, and eliminating the chromophore.
Carotenoids like lycopene are important pigments found in photosynthetic pigment-protein complexes in plants, photosynthetic bacteria, fungi, and algae. They are responsible for the bright 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.
The biosynthesis of lycopene in eukaryotic plants and in prokaryotic cyanobacteria is similar, as are the enzymes involved.[6] 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.[7]
| Dietary sources of lycopene[8] | |
|---|---|
| Source | μg/g wet weight |
| Gac | 2,000–2,300 |
| Raw tomato | 8.8–42 |
| Tomato juice | 86–100 |
| Tomato sauce | 63–131 |
| Tomato ketchup | 124 |
| Watermelon | 23–72 |
| Pink grapefruit | 3.6–34 |
| Pink guava | 54 |
| Papaya | 20–53 |
| Rosehip puree | 7.8 |
| Apricot | < 0.1 |
Fruits and vegetables that are high in lycopene include gac, tomatoes, watermelon, pink grapefruit, pink guava, papaya, red bell pepper, seabuckthorn, wolfberry (goji, a berry relative of tomato), and rosehip. Although gac (Momordica cochinchinensis Spreng) has the highest content of lycopene of any known fruit or vegetable, up to 70 times more than tomatoes for example[9], due to gac's rarity outside its native region of SE Asia, tomatoes and tomato based sauces, juices, and ketchup account for more than 85% of the dietary intake of lycopene for most people.[10] The lycopene content of tomatoes depends on species and increases as the fruit ripens.[11]
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. Lycopene in tomato paste is four times more bioavailable than in fresh tomatoes. For this reason, tomato sauce is a preferable source as opposed to raw tomatoes.
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.
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. Gac is a notable exception containing high concentrations of lycopene and also saturated and unsaturated fatty acids.[12]
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 promising commercial source of lycopene for the purposes of extraction and purification.
The cis-lycopene from some varieties of tomato is more bioavailable.[13]
| Distribution of lycopene[14] | |
|---|---|
| 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 |
After ingestion, lycopene is incorporated into lipid micelles in the small intestine. These micelles are formed from dietary fats and bile acids, and help to solubilize the hydrophobic lycopene and allow it to permeate the intestinal mucosal cells by a passive transport mechanism. Little is known about the liver metabolism of lycopene, but like other carotenoids, lycopene is incorporated into chylomicrons and released into the lymphatic system. In blood plasma, lycopene is eventually distributed into the very low and low density lipoprotein fractions.[15] Lycopene is mainly distributed to fatty tissues and organs such as the adrenal glands, liver, and testes.
Lycopene is non-toxic and is commonly found in the diet, but cases of excessive carotenoid intake have been reported. In a middle aged woman who had prolonged and excessive consumption of tomato juice, her skin and liver were colored orange-yellow and she had elevated levels of lycopene in her blood. After three weeks on a lycopene-free diet her skin color returned to normal.[15] This discoloration of the skin is known as lycopenodermia[16] and is non-toxic.
Lycopene may be the most powerful carotenoid quencher of singlet oxygen[17], being 100 times more efficient in test tube studies of singlet-oxygen quenching action than vitamin E, which in turn has 125 times the quenching action of glutathione (water soluble)[citation needed]. Singlet oxygen produced during exposure to ultraviolet light is a primary cause of skin aging.[18]
Given its antioxidant properties, substantial scientific and clinical research has been devoted to a possible correlation between lycopene consumption and general health. Early research suggested some amelioration { combating of } of cardiovascular disease, cancer, diabetes, osteoporosis, and even male infertility.[19]
After extensive review reported in November 2005, the United States Food and Drug Administration has cast significant doubt on the potential for lowering disease risk, showing no link between lycopene and prevention of prostate cancer, although it is suggestive that eating whole tomatoes does provide benefit, perhaps because as yet undiscovered compounds (other than lycopene) are the beneficial agents.[20] The FDA review permitted a highly limited qualified claim to be used for tomatoes and tomato products which contain lycopene, as a guide that would not mislead consumers, namely:
Very limited and preliminary scientific research suggests that eating one-half to one cup of tomatoes and/or tomato sauce a week may reduce the risk of prostate cancer. FDA concludes that there is little scientific evidence supporting this claim.
The related carotenoid antioxidant, beta-carotene, has been shown to increase the number of prostate cancer cases in a subset of patients,[21] although this area of research remains controversial and ongoing.
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This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
 | tetraterpene (organic chemistry) |
| carotene |
| carotenoid |
 | As lycopene being the precursor of bixin which type of lycopene is converting to bixin either cis or trans? |
| What is the structural formula of lycopene? |
| What are the methods of extraction of lycopene? |
Copyrights:
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 | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved. Read more |
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| Food and Nutrition. A Dictionary of Food and Nutrition. Copyright © 1995, 2003, 2005 by A. E. Bender and D. A. Bender. All rights reserved. Read more |
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| Alternative Medicine Encyclopedia. Encyclopedia of Alternative Medicine. Copyright © 2005 by The Gale Group, Inc. All rights reserved. Read more |
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| Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Lycopene". Read more |
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