Dictionary:

lycopene

  (lī'kə-pēn')

A red carotenoid pigment, C₄₀H₅₆, found chiefly in blood, the reproductive organs, tomatoes, and palm oils.

[Alteration of earlier lycopin : New Latin Lycop(ersicon), tomato genus (Greek lukos, wolf + Greek persikon, peach, from persikē, peach tree; see peach¹) + –IN.]

Red carotenoid pigment found in tomato, pink grapefruit, and palm oil. Not vitamin A active, but an antioxidant; also used as a food colour.

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.

• tomatoes, fresh (0.9–4.2)
• tomatoes, cooked (3.7)
• tomato sauce (6.2)
• tomato paste (5.4–150)
• tomato soup, condensed (8.0)
• tomato juice (5.0–11.6)
• sun-dried tomato in oil (46.5)
• pizza sauce, canned (12.7)
• ketchup (9.9–13.4)

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]

Lycopene
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
CAS number	502-65-8
PubChem	446925
EINECS number	207-949-1
SMILES	CC(=CCC/C(=C/C=C/C(=C/C=C/C(=C/C=C/C=C(\C) /C=C/C=C(\C)/C=C/C=C(\C)/CCC=C(C)C)/C)/C)/C)C
Properties
Molecular formula	C40H56
Molar mass	536.873 g/mol
Appearance	Deep red solid
Melting point	172–173 °C
Solubility in water	Insoluble
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Lycopene is a bright red carotenoid pigment, a phytochemical found in tomatoes and other red fruits. Lycopene is the most common carotenoid in the human body and is one of the most potent carotenoid antioxidants. Its name is derived from the tomato's species classification, Solanum lycopersicum (formerly Lycopersicon esculentum).

Structure and chemistry

Lycopene is a terpene assembled from 8 isoprene units.

The color of lycopene is due to its many conjugated carbon double bonds. Each double bond 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 most of the visible spectrum, so it appears red.

If lycopene is oxidized (for example, by reacting with bleaches or acids), the double bonds between carbon atoms will be broken, cleaving the molecule into smaller molecules each double-bonded to an oxygen atom. Although C=O bonds are also chromophoric, the much shorter molecules are unable to absorb enough light to appear colorful. A similar effect occurs if lycopene is reduced; reduction may saturate (convert the double bonds to single bonds) the lycopene molecule, diminishing its ability to absorb light.

Dietary sources

Fruits and vegetables that are high in lycopene include tomatoes, watermelon, pink grapefruit, pink guava, papaya, gac, and rosehip.

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. This is because lycopene is so insoluble in water and is so tightly bound to vegetable fiber. Thus processed tomato products such as pasteurized tomato juice, soup, sauce, and ketchup contain the highest concentrations of bioavailable lycopene. 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.

Production

Lycopene may be obtained from vegetables and fruits such as the tomato, but another source of lycopene is the fungus Blakeslea trispora.

Nutritional benefits

Lycopene is the most powerful carotenoid quencher of singlet oxygen^[1], being 100 times more efficient in the singlet-oxygen quenching action than Vitamin E, which in turn has 125 times the quenching action of glutathione (water soluble). Singlet oxygen produced during exposure to ultraviolet light is a primary cause of skin aging.^[2]

Given its antioxidant properties, some scientific research has investigated the correlation between lycopene consumption and general health. Early research suggested some amelioration of cardiovascular disease, cancer, diabetes, osteoporosis, and even male infertility.^{[3] [4][5]}. The most recent study, however, has cast significant doubt on these benefits, showing no link between lycopene and cancer prevention. In fact, a related antioxidant, beta-carotene, was shown to increase the number of prostate cancer cases^[6].

Food coloring

Due to its ubiquity, lycopene has been licensed for use as a food coloring.

Lycopene is not water-soluble and instantly stains 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, soap, or detergent. (Bleach will destroy lycopene, however.) Plastics are especially susceptible to staining if heated, scratched, oiled, or pitted, for example by acids.

Formulations Available

Lycopene is available in the market as mix formulation with some other carotinoids and antioxidants. It is marketed by a number of pharmaceutical companies under different brand names. Some commonly available formulations are LYCORED, LYNET, LYCORICH etc.

References

1. ^ Di Mascio P, Kaiser S, Sies H (1989). "Lycopene as the most efficient biological carotenoid singlet oxygen quencher". Archives of Biochemistry and Biophysics 274 (2): 532–538. PMID 2802626. 
2. ^ Berneburg M, Grether-Beck S, Kurten V, Ruzicka T, Briviba K, Sies H, Krutmann J (1999). "Singlet oxygen mediates the UVA-induced generation of the photoaging-associated mitochondrial common deletion". The Journal of Biological Chemistry 274 (22): 15345–15349. PMID 10336420. 
3. ^ Giovannucci, E. et al (1995). "Intake of Carotenoids and Retinol in Relation to Risk of Prostate Cancer". Journal of the National Cancer Institute. 
4. ^ Bowen P, Chen L, Stacewicz-Sapuntzakis M, Duncan C, Sharifi R, Ghosh L, Kim HS, Christov-Tzelkov K, van Breemen R (2002). "Tomato sauce supplementation and prostate cancer: lycopene accumulation and modulation of biomarkers of carcinogenesis". Experimental Biology and Medicine 227 (10): 886–893. PMID 12424330. 
5. ^ "http://news.bbc.co.uk/2/3086013.stm" BBC News - 22 July 2003
6. ^ American Association for Cancer Research. "No Magic Tomato? Study Breaks Link between Lycopene and Prostate Cancer Prevention", Science Daily, May 17, 2007. 

• Gerster, H. The potential role of lycopene for human health. J. Amer. Coll. Nutr. 16: 109–126, 1997
• Stahl, W. and Sies, H. lycopene: a biologically important carotenoid for humans? Arch. Biochem. Biophys. 336: 1–9, 1996

External links

• [1]
• [2]
• A website promoting a lycopene rich diet

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