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Carotene

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Carotene



 
 
The term carotene is used for several related substances having the formula C40Hx, which are synthesized by plants but cannot be made by animals. Carotene is an orange photosynthetic pigment
Photosynthetic pigment

A photosynthetic pigment is a pigment that is present in chloroplasts or photosynthetic bacterium and captures the light energy necessary for photosynthesis....
 important for photosynthesis
Photosynthesis

File:Seawifs global biosphere.jpgPhotosynthesis is a metabolic pathway that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight....
. Carotenes are responsible for the orange colour of the carrot
Carrot

The carrot is a root vegetable, usually orange or white, or red-white blend in colour, with a crisp texture when fresh. The edible part of a carrot is a taproot....
 and many other fruits and vegetables (for example, sweet potatoes and orange cantaloupe
Cantaloupe

Cantaloupe refers to two varieties of muskmelon , which is a species in the family Cucurbitaceae . Cantaloupes are typically 15?25 cm in length and are somewhat oblong, though not as oblong as watermelons....
 melon).






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Carrotdiversitylg
The term carotene is used for several related substances having the formula C40Hx, which are synthesized by plants but cannot be made by animals. Carotene is an orange photosynthetic pigment
Photosynthetic pigment

A photosynthetic pigment is a pigment that is present in chloroplasts or photosynthetic bacterium and captures the light energy necessary for photosynthesis....
 important for photosynthesis
Photosynthesis

File:Seawifs global biosphere.jpgPhotosynthesis is a metabolic pathway that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight....
. Carotenes are responsible for the orange colour of the carrot
Carrot

The carrot is a root vegetable, usually orange or white, or red-white blend in colour, with a crisp texture when fresh. The edible part of a carrot is a taproot....
 and many other fruits and vegetables (for example, sweet potatoes and orange cantaloupe
Cantaloupe

Cantaloupe refers to two varieties of muskmelon , which is a species in the family Cucurbitaceae . Cantaloupes are typically 15?25 cm in length and are somewhat oblong, though not as oblong as watermelons....
 melon). Carotenes are also responsible for the orange colours in dry foliage. They also (in lower concentrations) impart the yellow colouration to milk-fat, butter, and egg yolk. Omnivorous animal species which are poor converters of coloured dietary carotenoids to colourless retinoids, have yellowed-coloured body fat as a result of the carotenoid retention. The typical yellow-coloured fat of humans and chickens is a result of fat storage of carotenes from their diets.

Carotenes contributes to photosynthesis by transmitting the light energy they absorb from chlorophyll
Chlorophyll

Chlorophyll is a green pigment found in most plants, algae, and cyanobacteria. Its name is derived from Greek language: ?????? and f????? ....
. They also protect plant tissues by helping to absorb the energy from singlet oxygen
Singlet oxygen

Singlet oxygen is the common name used for the diamagnetic form of molecular oxygen , which is less stable than the normal triplet oxygen. Because of its unusual properties, singlet oxygen can persist for over an hour at room temperature, depending on the environment....
, an excited form of the oxygen molecule O2 which is formed during photosynthesis.

Chemically, carotene is a terpene
Terpene

Terpenes are a large and varied class of hydrocarbons, produced primarily by a wide variety of plants, particularly conifers, though also by some insects such as termites or swallowtail butterflies, which emit terpenes from their osmeterium....
, synthesized biochemically from eight isoprene
Isoprene

Isoprene is a common synonym for the chemical compound 2-methyl-1,3-butadiene. It is commonly used in industry, is an important biological material, and can be a harmful environmental pollutant and toxicant when present in excess quantities....
 units. It comes in two primary forms designated by characters from the Greek alphabet
Greek alphabet

The Greek alphabet is a set of twenty-four letters that has been used to write the Greek language since the late 9th century BC or early 8th century BCE....
: alpha-carotene
Alpha-carotene

α-Carotene is a form of carotene with a ?-ring at one end and an e-ring at the other. It is the second most common form of carotene....
 (a-carotene) and beta-carotene
Beta-carotene

?-Carotene is an organic compound - a terpenoid, a red-orange pigment abundant in plants and fruits. As a carotene with ?-rings at both ends, it is the most common form of carotene....
 (ß-carotene). Gamma, delta, epsilon, and zeta (?, d, e, and ?-carotene) also exist. As hydrocarbons which contain no oxygen, carotenes are fat-soluble and insoluble in water (in contrast with other carotenoids, such as xanthophyll
Xanthophyll

Xanthophylls are yellow pigments from the carotenoid group. Their molecular structure is based on carotenes; contrary to the carotenes, some hydrogen atoms are substituted by hydroxyl groups and/or some pairs of hydrogen atoms are substituted by oxygen atoms....
s, which are slightly less chemically hydrophobic).

Beta-carotene is composed of two retinyl
Retinol

Retinol, the animal form of vitamin A, is a fat-soluble vitamin important in visual system and bone growth. It is also a Terpenoid. Retinol is among the most useable forms of vitamin A, which also include Retinal , Retinoic acid and retinyl ester ....
 groups, and is broken down in the mucosa of the small intestine
Small intestine

In vertebrates, including mammals, reptiles, birds, and bony fish, the small intestine is the part of the gastrointestinal tract following the stomach, and is where the vast majority of digestion takes place....
 by beta-carotene 15,15'-monooxygenase
Beta-carotene 15,15'-monooxygenase

In enzymology, a beta-carotene 15,15'-monooxygenase is an enzyme that catalysis the chemical reactionThus, the two substrate of this enzyme are beta-carotene and oxygen, whereas its product is retinal....
 to retinal
Retinal

Retinal, also called retinaldehyde or vitamin A aldehyde, is one of the three forms of vitamin A. Retinal is a polyene chromophore, and bound to proteins called opsins, is the chemical basis of animal vision....
, a form of vitamin A
Vitamin A

Vitamin A, a bi-polar molecule formed with bi-polar covalent bonds between carbon and hydrogen, is linked to a family of similarly shaped molecules, the retinoids, which complete the remainder of the vitamin sequence....
. Carotene can be stored in the liver
Liver

The liver is a vital organ present in vertebrates and some other animals; it has a wide range of functions, a few of which are detoxification, protein synthesis, and production of biochemicals necessary for digestion....
 and body fat and converted to retinal as needed, thus making it a form of vitamin A
Vitamin A

Vitamin A, a bi-polar molecule formed with bi-polar covalent bonds between carbon and hydrogen, is linked to a family of similarly shaped molecules, the retinoids, which complete the remainder of the vitamin sequence....
 for humans and some other mammals.

Animal species differ greatly in their ability to convert carotene to retinals. Carnivores in general are poor converters of dietary carotenoids, and pure carnivores such as cats and ferets lack beta-carotene 15,15'-monooxygenase
Beta-carotene 15,15'-monooxygenase

In enzymology, a beta-carotene 15,15'-monooxygenase is an enzyme that catalysis the chemical reactionThus, the two substrate of this enzyme are beta-carotene and oxygen, whereas its product is retinal....
 and cannot convert carotenoids to retinals at all (resulting in carotenes not being a form of vitamin A for these species).

Dietary sources


The following foods are particularly rich in carotenes (see Vitamin A
Vitamin A

Vitamin A, a bi-polar molecule formed with bi-polar covalent bonds between carbon and hydrogen, is linked to a family of similarly shaped molecules, the retinoids, which complete the remainder of the vitamin sequence....
 article for amounts):

  • sweet potatoes
  • carrots
  • goji berries
  • cantaloupe melon
  • mango
    Mango

    Mangoes belong to the genus Mangifera, consisting of numerous species of tropical fruiting trees in the flowering plant family Anacardiaceae....
  • apricots
  • spinach
    Spinach

    Spinach is a flowering plant in the family of Amaranthaceae. It is native to central and southwestern Asia. It is an annual plant , which grows to a height of up to 30 cm....
  • kale
    Kale

    Kale or Borecole is a form of cabbage , green in color, in which the central leaves do not form a head. It is considered to be closer to wild cabbage than most domesticated forms....
  • chard
    Chard

    Chard , also known by the common names Swiss Chard, Silverbeet, Perpetual Spinach, Spinach Beet, Crab Beet, Seakale Beet and Mangold, is a leafy vegetable and a Beta vulgaris subsp....
  • turnip greens
  • dandelion greens
  • beet greens
  • mustard greens
  • collard greens
    Collard greens

    Collards are various loose-leafed cultivars of Brassica oleracea , the same species that produces cabbage and broccoli. The plant is grown for its large, dark-colored, greens and as a garden ornamental, mainly in Brazil, Portugal, the Southern United States, many parts of Africa, Montenegro, Spain and in Kashmir....
  • watercress
    Watercress

    Watercresses are fast-growing, aquatic or semi-aquatic, perennial plants native from Europe to central Asia, and one of the oldest known leaf vegetables consumed by human beings....
  • cilantro
  • fresh thyme
    Thyme

    Thyme is a well known herb; in common usage the name may refer to* any or all members of the plant genus Thymus ,* common thyme, Thymus vulgaris, and some other species that are used as culinary herbs or for medicinal purposes....
  • broccoli
    Broccoli

    Broccoli is a plant of the cabbage family Brassicaceae .It is classified as the Italica cultivar group of the species Brassica oleracea. Broccoli possesses abundant arboreal, luscious, fleshy, flower heads, usually green in color, arranged in a tree-like fashion on branches sprouting from a thick, edible, sturdy, meaty stalk....
  • parsley
    Parsley

    Parsley is a bright green, biennial plant herb, also used as spice. It is very common in Middle Eastern cuisine, European cuisine, and American cuisine cooking....
  • romaine lettuce
    Romaine lettuce

    Romaine or cos lettuce is a variety of lettuce which grows in a long head of sturdy leaves with a firm rib down the center. Unlike most lettuces, it is tolerant of heat....
  • ivy gourd
  • rose hips
  • winter squash
    Winter squash

    Winter squash is a warm-seasoned vegetable, representing several species within the genus Cucurbita. It differs from summer squash in that it is harvested and eaten in the mature fruit stage, when the seeds within have matured fully and the skin has hardened into a tough rind....
  • pumpkin
    Pumpkin

    Pumpkin is a gourd-like Squash of the genus Cucurbita and the family Cucurbitaceae . It is a common name of or can refer to cultivars of any one of the following species: Cucurbita pepo, Cucurbita mixta, Cucurbita maxima, and Cucurbita moschata....
  • cassava
    Cassava

    The cassava, cassadaIn page 25, Darwin says "Mandioca or cassada is likewise cultivated in great quantity."See it also in ,yuca, 'manioc, 'mogo...


Absorption from these foods is enhanced if eaten with fats, as carotenes are fat soluble, and if the food is cooked for a few minutes until the plant cell wall
Cell wall

A cell wall is a tough, flexible and sometimes fairly rigid layer that surrounds some types of cell . It is located outside the cell membrane and provides these cells with structural support and protection, and also acts as a filtering mechanism....
 splits and the colour is released into any liquid. 6 µg of dietary ß-carotene supplies the equivalent of 1 µg of retinol, or 1 RE (Retinol Equivalent). This is equivalent to 3? IU
International unit

In pharmacology, the International Unit is a unit of measurement for the amount of a substance, based on measured biological activity or effect....
 of vitamin A.

The multiple forms

The two primary isomer
Isomer

In chemistry, isomers are compounds with the same molecular formula but different structural formulae. Isomers do not necessarily share similar properties unless they also have the same functional groups....
s of carotene, a-carotene and ß-carotene, differ in the position of double bonds in the cyclic group at the end.

ß-Carotene is the more common form and can be found in yellow
Yellow

Yellow is the color evoked by light that stimulates both the L and M cone cells of the retina about equally, but does not significantly stimulate the S cone cells; that is, light with much red and green but not very much blue....
, orange
Orange (colour)

The color orange occurs between red and yellow in the visible Optical spectrum at a wavelength of about 585 ? 620 nanometre, and has a hue of 30? in HSV colour space....
, and green
Green

Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520?570-Nanometre....
 leafy fruit
Fruit

The term fruit has different meanings dependent on context, and the term is not synonymous in food preparation and biology. In botany, which is the scientific study of plants, fruits are the ripened Ovary of flowering plants....
s and vegetable
Vegetable

The term "vegetable" generally means the Eating parts of plants. The definition of the word is traditional rather than scientific, however, and therefore the usage of the word is somewhat arbitrary and subjective, as it is determined by individual cultural customs of food selection and food preparation....
s. As a rule of thumb
Rule of thumb

A rule of thumb is a principle with broad application that is not intended to be strictly accurate or reliable for every situation. It is an easily learned and easily applied procedure for approximately calculating or recalling some value, or for making some determination....
, the greater the intensity of the orange colour of the fruit or vegetable, the more ß-carotene it contains.

Carotene protects plant cells against the destructive effects of ultraviolet light. ß-Carotene is an anti-oxidant.

Beta-carotene and cancer

It has been shown in trials that the ingestion of beta carotene at about 30 mg/day (10 times the Reference Daily Intake
Reference Daily Intake

Reference Daily Intake is the daily dietary intake level of a nutrient which was considered to be sufficient to meet the requirements of nearly all healthy individuals in each life-stage and sex group....
) increases the rate of lung cancer and prostate cancer, and increases mortality in smoker
Smoker

Smoker is a noun derived from "smoke"/"smoking" and may have the following specialized meanings:*Someone who smokes Tobacco smoking or cannabis , cigarette substitutes or various other drugs...
s and people with a history of asbestos
Asbestos

Asbestos is a naturally occurring silicate mineral with long, thin fibrous crystals. The word asbestos is derived from a Greek language adjective meaning inextinguishable....
 exposure.

An article on the American Cancer Society
American Cancer Society

The American Cancer Society is the "nationwide community-based voluntary health organization dedicated to eliminating cancer as a major health problem by preventing cancer, saving lives, and diminishing suffering from cancer, through research, education, advocacy and service."...
 says that The Cancer Research Campaign has called for warning labels on beta carotene supplements to caution smokers that such supplements may increase the risk of lung cancer.

The New England Journal of Medicine published an article in 1994 about a trial which examined the relationship between daily supplementation of beta carotene and vitamin E
Vitamin E

Vitamin E is the collective name for a set of 8 related a-, ?-, ?-, and d-tocopherols and the corresponding four tocotrienols, which are fat-soluble vitamins with antioxidant properties....
 (alpha-tocopherol) and the incidence of lung cancer. The study was done using supplements and researchers were aware of the epidemiological correlation between carotenoid-rich fruits and vegetables and lower lung cancer rates. The research concluded that no reduction in lung cancer was found in the participants using these supplements (beta-carotene), and furthermore, these supplements may, in fact, have harmful effects.

The Journal of the National Cancer Institute
National Cancer Institute

The National Cancer Institute is part of the United States Federal government's National Institutes of Health. The NCI is a federally funded research and development center, one of eight agencies that compose the United States Public Health Service in the United States Department of Health and Human Services....
 published an article in 1996 about a trial that was conducted to determine if vitamin A (in the form of retinyl palmitate) and beta carotene had any beneficial effects to prevent cancer. The results indicate an increased risk of lung cancer for the participants who consumed the beta-carotene supplement.

A randomised trial into the use of ß-carotene and vitamin A for prevention of lung cancer had to be stopped early due to the apparent increase in the incidence of lung cancer
Lung cancer

Lung cancer is a disease of uncontrolled cell growth in tissue of the lung. This growth may lead to metastasis, which is the invasion of adjacent tissue and infiltration beyond the lungs....
 in those with lung irritation from smoking
Tobacco smoking

Tobacco smoking is the inhalation of smoke from burned dried or cured leaves of the tobacco plant, most often in the form of a cigarette. People may smoke casually for pleasure, habitually to satisfy an addiction to the nicotine present in tobacco and to the act of smoking, or in response to social pressure....
 or asbestos
Asbestos

Asbestos is a naturally occurring silicate mineral with long, thin fibrous crystals. The word asbestos is derived from a Greek language adjective meaning inextinguishable....
 exposure.

A review of all randomized controlled trials in the scientific literature by the Cochrane Collaboration
Cochrane Collaboration

The Cochrane Collaboration is a group of over 15,000 volunteers in more than 90 countries who apply a rigorous, systematic process to review the effects of health care interventions tested in biomedical randomized controlled trials....
 published in JAMA
Journal of the American Medical Association

JAMA: The Journal of the American Medical Association is an international peer-reviewed general medical journal, published 48 times per year by the American Medical Association....
 in 2007 found that beta carotene increased mortality by something between 1 and 8% (Relative Risk 1.05, 95% confidence interval 1.01-1.08). However, this meta-analysis included two large studies of smokers, so it is not clear that the results apply to the general population.

Beta carotene and cognition

A recent report demonstrated that 50mg of beta carotene every other day prevented cognitive decline in a study of over 4000 physicians at a mean treatment duration of 18 years.

Beta carotene and photosensitivity

Oral Beta-carotene is prescribed to people suffering from Erythropoietic protoporphyria. It provides them some relief of the photosensitivity.

Carotenemia

Carotenemia or hypercarotenemia is excess carotene, but unlike excess vitamin A, carotene is non-toxic. Although hypercarotenemia is not particularly dangerous, it can lead to a yellowing of the skin (carotenodermia), but not the conjunctiva
Conjunctiva

The conjunctiva is a clear mucous membrane consisting of cells and underlying basement membrane that covers the sclera and lines the inside of the eyelids....
 of eyes (thus easily distingishing it visually from jaundice
Jaundice

Jaundice, also known as icterus , is a yellowish discoloration of the skin, the conjunctival membranes over the sclera , and other mucous membranes caused by hyperbilirubinemia ....
). It is most commonly associated with consumption of an abundance of carrot
Carrot

The carrot is a root vegetable, usually orange or white, or red-white blend in colour, with a crisp texture when fresh. The edible part of a carrot is a taproot....
s, but it also can be a medical sign
Medical sign

A medical sign is an Objectivity indication of some medical fact or characteristic that may be detected by a physician during a physical examination of a patient....
 of more dangerous conditions.

Production

Most of the world's synthetic supply of carotene comes from a manufacturing complex located in Freeport, Texas
Freeport, Texas

Freeport is a city in Brazoria County, Texas, Texas within the Houston Metropolitan Area and is situated in Southeast Texas. As of the 2000 U.S....
 and owned by DSM
DSM (company)

DSM is a multinational company specialized in Life Sciences and Materials Sciences. Its headquarters are in Heerlen, the Netherlands. Originally a state-owned coal mining company , the activities of DSM are now grouped into five clusters:...
. The other major supplier BASF
BASF

BASF SE is a German chemical company and the largest chemical company in the world. BASF originally stood for Badische Anilin- und Soda-Fabrik ....
 also uses a chemical process to produce beta carotene. Together these suppliers account for about 85% of the beta carotene on the market. In Spain Vitatene produces natural beta carotene from Blakeslea trispora, as does DSM but at much lower amount when compared to its synthetic beta carotene operation. In Australia, organic beta-carotene is produced by Aquacarotene Limited from dried marine algae Dunaliella salina
Dunaliella salina

Dunaliella salina is a type of halophile pink micro-algae especially found in sea salt fields. Known for its anti-oxidant activity because of its ability to create large amount of carotenoids....
 grown in harvesting ponds situated in Karratha, Western Australia
Karratha, Western Australia

Karratha is a town adjoining the port of Dampier in the Pilbara region of Western Australia which was developed from the 1960s to accommodate the processing and exportation workforce of the Hamersley Iron iron ore company and, in the 1980s, the petroleum and liquefied natural gas operations of the North West Shelf Venture....
. Cognis Australia Pty. Ltd., a subsidiary of the Germany-based company Cognis
Cognis

Cognis is a worldwide supplier of specialty chemicals and nutritional ingredients, headquartered in Monheim, Germany. The company employs about 7,600 people and operates production or service centers in almost 30 countries....
, is also producing beta carotene from microalgae grown in two sites in Australia that are the world’s largest algae farms. In Portugal
Portugal

Portugal , officially the Portuguese Republic , is a country on the Iberian Peninsula. Located in southwestern Europe, Portugal is the westernmost country of mainland Europe and is bordered by the Atlantic Ocean to the west and south and by Spain to the north and east....
, the industrial biotechnology
Industrial biotechnology

Industrial biotechnology is the application of biotechnology for industrial purposes, including manufacturing, alternative energy , and biomaterials....
 company Biotrend is producing natural all-trans beta carotene from a non genetically modified bacteria of the Sphingomonas
Sphingomonas

Sphingomonas was defined in 1990 as a group of Gram-negative, rod-shaped, chemoheterotrophic, strictly aerobic organism bacteria. They possess ubiquinone 10 as their major respiratory quinone, contain glycosphingolipids instead of lipopolysaccharide in their cell envelopes, and typically produce yellow-pigmented colonies....
 genus isolated from soil.

Carotene is also found in palm oil, corn, and in the milk of dairy cows, causing cow's milk to be light yellow, depending on the feed of the cattle, and the amount of fat in the milk (high-fat milks, such as those produced by Guernsey
Guernsey

The Bailiwick of Guernsey is a British Isles Crown dependency in the English Channel off the coast of Normandy.As well as the island of Guernsey itself, it also includes Alderney, Sark, Herm, Jethou, Brecqhou, Burhou, Lihou and other islets....
 cows, tend to be more yellow because their fat content causes them to contain more carotene).

Carotenes are also found in some species of termites, where they apparently have been picked up from the diet of the insects.

Total synthesis

There are currently two commonly used methods of total synthesis
Total synthesis

In principle a total synthesis is the complete chemical synthesis of complex Organic compound molecules from simpler pieces, usually without the aid of biological processes....
 of ß-carotene. The first was developed by the Badische Anilin- & Soda-Fabrik (BASF
BASF

BASF SE is a German chemical company and the largest chemical company in the world. BASF originally stood for Badische Anilin- und Soda-Fabrik ....
) and is based on the Wittig reaction
Wittig reaction

The Wittig reaction is a chemical reaction of an aldehyde or ketone with a triphenyl #Wittig reagents to give an alkene and triphenylphosphine oxide....
. The second is a Grignard reaction
Grignard reaction

The Grignard reaction, named after the French chemist Fran?ois Auguste Victor Grignard, is an organometallic chemistry chemical reaction in which alkyl- or aryl-magnesium halides , act as nucleophiles, attack electrophilic carbon atoms that are present within polar bonds to yield a carbon-carbon bond , thus altering hybridization about the r...
, elaborated by Hoffman-La Roche from the original synthesis of Inhoffen et al. They are both symmetrical; the BASF synthesis is C20 + C20 , and the Hoffman-La Roche synthesis is C19 + C2 + C19.

Nomenclature

Carotenes are carotenoids containing no oxygen. Carotenoids containing some oxygen are known as xanthophyll
Xanthophyll

Xanthophylls are yellow pigments from the carotenoid group. Their molecular structure is based on carotenes; contrary to the carotenes, some hydrogen atoms are substituted by hydroxyl groups and/or some pairs of hydrogen atoms are substituted by oxygen atoms....
s.

The two ends of the ß-carotene molecule are structurally identical, and are called ß-rings. Specifically, the group of nine carbon atoms at each end form a ß-ring.

The a-carotene molecule has a ß-ring at one end; the other end is called an e-ring. There is no such thing as an "a-ring".

These and similar names for the ends of the carotenoid molecules form the basis of a systematic naming scheme, according to which:
  • a-carotene is ß,e-carotene;
  • ß-carotene is ß,ß-carotene;
  • ?-carotene (with one ß ring and one uncyclized end that is labelled psi
    Psi (letter)

    Psi is the 23rd letter of the Greek alphabet and has a Greek numerals value of 700. In both Classical Greek and Modern Greek, the letter indicates the combination /ps/ ....
    ) is ß,?-carotene;
  • d-carotene (with one e ring and one uncyclized end) is e,?-carotene;
  • e-carotene is e,e-carotene
  • lycopene
    Lycopene

    Lycopene is a bright red carotenoid pigment and phytochemical found in tomatoes and other red fruits.In plants, algae, and other Photosynthesis, 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....
     is ?,?-carotene


That leaves ?-carotene; ?-carotene is the biosynthetic
Biosynthesis

Biosynthesis is a phenomenon wherein chemical compounds are produced from simpler reagents. Biosynthesis, unlike chemosynthesis, takes place within living organisms and is generally catalyst by enzymes....
 precursor
Precursor (chemistry)

In chemistry, a precursor is a chemical compound that participates in the chemical reaction that produces another compound. In biochemistry, the term "precursor" is used more specifically to refer to a chemical compound preceding another in a metabolic pathway....
 of neurosporene, which is the precursor of of lycopene, which, in turn, is the precursor of the carotenes a through e. ? comes first.

See also

  • Antioxidant
    Antioxidant

    An antioxidant is a molecule capable of slowing or preventing the Redox of other molecules. Oxidation is a chemical reaction that transfers electrons from a substance to an oxidizing agent....
  • Phytonutrients


External links

  • , University of Bristol
    University of Bristol

    The University of Bristol is a university in Bristol, England. It received its Royal Charter in 1909, although its predecessor institution, University College, Bristol, had been in existence since 1876....
  • on University of Maryland Medical Center