Polyphenol

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Polyphenol

Polyphenols are a group of chemical substances found in plants, characterized by the presence of more than one phenol

Phenol

Phenol, also known as carbolic acid, is a toxic, white crystalline solid with a sweet tarry odor, commonly referred to as a "hospital smell"....
unit or building block per molecule. Polyphenols are generally divided into hydrolyzable tannins (gallic acid

Gallic acid

Gallic acid is an organic acid, also known as 3,4,5-trihydroxybenzoic acid, found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants....
esters of glucose

Glucose

Glucose , a monosaccharide also known as grape sugar, blood sugar, or corn sugar, is a very important carbohydrate in biology....
and other sugars) and phenylpropanoid

Phenylpropanoid

Phenylpropanoids are a class of plant-derived organic compounds that are biosynthesized from the amino acid phenylalanine. They have a wide variety of functions, including defense against Herbivory, microbial attack, or other sources of injury; as structural components of cell walls; as protection from ultraviolet light; as pigments; and as...
s, such as lignin

Lignin

Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae....
s, flavonoid

Flavonoid

The term flavonoid refers to a class of plant secondary metabolites. According to the IUPAC nomenclature, they can be classified into:*flavonoids, derived from 2-phenylchromone structure...
s, and condensed tannins.

division of polyphenols into tannins, lignins, and flavonoids is derived from the variety of simple polyphenolic units derived from secondary plant metabolism of the shikimate pathway as well as classical divisions based upon the relative importance of each base component to different fields of study.

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Encyclopedia

Polyphenols are a group of chemical substances found in plants, characterized by the presence of more than one phenol

Phenol

Gallic acid

Gallic acid is an organic acid, also known as 3,4,5-trihydroxybenzoic acid, found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants....
esters of glucose

Glucose

Glucose , a monosaccharide also known as grape sugar, blood sugar, or corn sugar, is a very important carbohydrate in biology....
and other sugars) and phenylpropanoid

Phenylpropanoid

Lignin

Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae....
s, flavonoid

Flavonoid

Chemistry

Classification and Nomenclature

The division of polyphenols into tannins, lignins, and flavonoids is derived from the variety of simple polyphenolic units derived from secondary plant metabolism of the shikimate pathway as well as classical divisions based upon the relative importance of each base component to different fields of study. Tannin chemistry originated in the importance of tannic acid

Tannic acid

Tannic acid , a commercial form of tannin, is a polyphenol. Its weak acidity is due to these phenol groups in the structure. Tannic acid is a basic ingredient in the chemical staining of wood....
to the tanning industry

Tanning

Tanning is the process of making leather, which does not easily Decomposition, from the skins of animals, which do. Often this uses tannin, an acidic chemical compound....
; lignins to the chemistry of soil

Soil

Soil is the naturally occurring, unconsolidated or loose covering on the Earth's surface. Soil is composed of particles of broken rock that have been altered by chemical and environmental processes including weathering and erosion....
and plant structure; and flavonoids to the chemistry of plant secondary metabolites for plant defense

Plant defense against herbivory

Plant defense against herbivory or host-plant resistance includes a range of adaptations evolved by plants that improve their fitness by reducing the impact of herbivores....
, and flower color (e.g. from anthocyanins).

The largest and best studied polyphenols are the flavonoids, which include several thousand compounds, among them the flavonols

Flavonols

Flavonols are a class of flavonoids that use the 3-hydroxyflavone backbone . Their diversity stems from the different positions the phenols hydroxyl groups....
, flavones

Flavones

Flavones are a class of flavonoids based on the backbone of 2-phenylchromen-4-one shown on the right.Natural flavones include Apigenin , Luteolin and Tangeritin ,chrysin,6-hydroxyflavone,baicalein , scutellarein,wogonin ....
, catechins, flavanones, anthocyanidins, and isoflavonoids.

The most abundant polyphenols are the condensed tannins, found in virtually all families of plants, and comprising up to 50% of the dry weight of leaves. The convergent evolution

Convergent evolution

Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action....
of tannin-rich plant communities has occurred on nutrient-poor acidic soils throughout the world. Tannins were once believed to function as anti-herbivore defenses, but more and more ecologists now recognize them as important controllers of decomposition and nitrogen cycling processes. As concern grows about global warming, there is great interest to better understand the role of polyphenols as regulators of carbon cycling, particularly in northern boreal forests.

Base Unit:	Gallic Acid Gallic acid Gallic acid is an organic acid, also known as 3,4,5-trihydroxybenzoic acid, found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants....	Flavone	Cinnamic acid Cinnamic acid Cinnamic acid has the formula C6H5CHCHCOOH and is a white crystalline acid, which is slightly soluble in water. It has a melting point of 133?C and a boiling point of 300?C....
Class/Polymer:	hydrolyzable tannins Tannin Tannins are astringent, bitter plant polyphenols that either bind and Precipitation or shrink proteins. The astringency from the tannins is what causes the dry and puckery feeling in the mouth following the consumption of red wine or an unripened fruit....	Flavonoid Flavonoid The term flavonoid refers to a class of plant secondary metabolites. According to the IUPAC nomenclature, they can be classified into:*flavonoids, derived from 2-phenylchromone structure... , condensed tannins Tannin Tannins are astringent, bitter plant polyphenols that either bind and Precipitation or shrink proteins. The astringency from the tannins is what causes the dry and puckery feeling in the mouth following the consumption of red wine or an unripened fruit....	Lignin Lignin Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae.... s

Polyphenols are also classified by the type and number of phenolic subcomponents present. More than one subcomponent can be present on a given polyphenol.


Phenol Phenol Phenol, also known as carbolic acid, is a toxic, white crystalline solid with a sweet tarry odor, commonly referred to as a "hospital smell"....	Pyrocatechol Pyrocatechol Catechol, formerly known as pyrocatechol, is the organic compound with the formula C6H42. It is one of three isomeric benzenediols. This colourless compound occurs naturally in trace amounts....	Pyrogallol Pyrogallol Pyrogallol or benzene-1,2,3-triol is a white crystalline powder and a powerful reducing agent. It was first prepared by Carl Wilhelm Scheele 1786 by heating gallic acid....	Resorcinol Resorcinol Resorcinol is a chemical compound from the dihydroxy phenols. It is the 1,3-isomer of benzenediol, and is also known with a variety of other names, including: m-dihydroxybenzene, 1,3-benzenediol, 1,3-dihydroxybenzene, 3-hydroxyphenol, m-hydroquinone, m-benzenediol, and 3-hydroxycyclohexadien-1-one....	Phloroglucinol Phloroglucinol Phloroglucinol is the organic compound that is used in the organic synthesis. This molecule exists in two forms, or tautomers, 1,3,5-trihydroxybenzene, which has phenol-like, and 1,3,5--cyclohexanetrione, which has ketone-like character....	Hydroquinone Hydroquinone Hydroquinone, also benzene-1,4-diol or quinol, is an aromatic organic compound which is a type of Phenols, having the chemical formula C6H42....
Examples: coumaric acid Coumaric acid Coumaric acids are organic compounds that are hydroxy derivatives of cinnamic acid. There are three isomers, o-coumaric acid, m-coumaric acid, and p-coumaric acid, that differ by the position of the hydroxy substitution of the phenyl group.... derived lignins, kaempferol Kaempferol Kaempferol is a natural flavonoid that has been isolated from tea, broccoli, Delphinium, Witch-hazel, grapefruit, and other plant sources. Kaempferol is a yellow crystalline solid with a melting point of 276-278 ?C....	Examples: catechin Catechin Catechins are polyphenolic antioxidant plant metabolites. They belong to the family of flavonoids and, to be more specific, flavonoid#subgroups.... , quercetin Quercetin Quercetin is a plant-derived flavonoid, specifically a flavonol, used as a nutritional supplement.The American Cancer Society says that quercetin "has been promoted as being effective against a wide variety of diseases, including cancer.... , caffeic Caffeic acid Caffeic acid, carbon9hydrogen8oxygen4 is a naturally occurring phenolic compound, , which is found in many fruits, vegetables, and herbs, including coffee, although varying in amounts depending on the plant.... and ferulic acid Ferulic acid Ferulic acid is an organic compound that is an abundant phenolic phytochemical found in plant cell walls. It is a derivative of trans-cinnamic acid.... derived lignins, hydroxytyrosol Hydroxytyrosol Hydroxytyrosol is a phytochemical with antioxidant properties. After gallic acid, hydroxytyrosol is believed to be one of the most powerful antioxidants.... esters	Examples: gallocatechins (EGCG Epigallocatechin gallate Epigallocatechin gallate , also known as Epigallocatechin 3-gallate, is the ester of epigallocatechin and gallic acid and a type of catechin.EGCG is the most abundant catechin in tea and an antioxidant that may have therapeutic properties for many disorders including cancer.... ), tannins, myricetin Myricetin Myricetin is a naturally occurring flavonol, a flavonoid found in many grapes, berries, fruits, vegetables, herbs, as well as other plants. Walnuts are a rich dietary source.... , sinapyl alcohol Sinapyl alcohol Sinapyl alcohol is an organic compound derived from cinnamic acid. This phytochemical is one of the monolignols. It is biosynthesis via the phenylpropanoid biochemical pathway, its immediate precursor being sinapaldehyde.... derived lignins	Examples: resveratrol Resveratrol Resveratrol is a phytoalexin produced naturally by several plants when under attack by pathogens such as bacteria or fungi. Resveratrol has also been produced by chemical synthesis and is sold as a nutritional supplement derived primarily from Japanese knotweed....	Examples: almost all flavonoid Flavonoid The term flavonoid refers to a class of plant secondary metabolites. According to the IUPAC nomenclature, they can be classified into:*flavonoids, derived from 2-phenylchromone structure... s	Examples: arbutin Arbutin Arbutin is both an ether and a glycoside; a glycosylated 1,4-Benzoquinone extracted from bearberry plant in the genus Arctostaphylos. It enzyme inhibitor tyrosinase and thus prevents the formation of melanin....

The phenolic unit can often be esterified

Esterification

Esterification is the general name for a chemical reaction in which two reactants form an ester as the product . Esters are common in organic chemistry and biological materials, and often have a characteristic pleasant, fruity odor....
or methylated

Methylation

Methylation in the chemical sciences denotes the attachment or substitution of a methyl on various Substrate . This term is commonly used in chemistry, biochemistry, soil science and the biological sciences....
. It can also be found dimerized or further polymerized, creating a new class of polyphenol. For example, ellagic acid

Ellagic acid

Ellagic acid is a polyphenol antioxidant found in numerous fruits and vegetables including raspberry, strawberry, cranberry, walnuts, pecans, pomegranates and other plant foods....
is a dimer of gallic acid and forms the class of ellagitannins, or a catechin

Catechin

Catechins are polyphenolic antioxidant plant metabolites. They belong to the family of flavonoids and, to be more specific, flavonoid#subgroups....
and a gallocatechin can combine to form the red compound theaflavin

Theaflavin

Theaflavin and its derivatives, known collectively as theaflavins, are polyphenols Flavan-3-ols that are formed from catechins such as in tea leaves during the enzymatic oxidation of tea leaves, such as in black tea....
, a process which also results in the large class of brown thearubigin

Thearubigin

Thearubigins are polymeric polyphenols that are formed during the enzyme oxidation of tea leaves. Thearubigins are red in colour. Therefore a black tea gives a reddish liquor while a green or white tea gives a much clearer one....
s in tea.

In Foods

Notable sources of polyphenols include berries, tea

Tea

Tea refers to the agricultural products of the leaves, leaf buds, and internodes of the Camellia sinensis plant, prepared and cured by various methods....
, beer

Beer

Beer is the world's oldest and most widely consumed alcoholic beverage and the third most popular drink overall after water and tea. It is produced by the brewing and Fermentation of starches, mainly derived from cereal?the most common of which is malted barley, although wheat, maize , and rice are widely used....
, grapes/wine

Wine

Wine is an alcoholic beverage often made of fermentation grape juice. The natural chemical balance of grapes is such that they can ferment without the addition of sugars, acids, enzymes or other nutrients....
, olive oil

Olive oil

Olive oil is a fruit oil obtained from the olive , a traditional tree crop of the Mediterranean Basin. The wild olive tree originated in Anatolia and spread from there as far as southern Africa, Australia, Japan and China....
, chocolate

Chocolate

Chocolate comprises a number of raw and processed foods that are produced from the seed of the tropical cacao tree.Chocolate has become one of the most popular flavors in the world....
/cocoa

Cocoa

Cocoa is the dried and fully fermented fatty seed of the cacao from which chocolate is made. "Cocoa" can often also refer to the drink commonly known as hot chocolate; Cocoa solids, the dry powder made by grinding cocoa seeds and removing the cocoa butter from the dark, bitter cocoa solids; or it may refer to the combination of both cocoa p...
, coffee

Coffee

Coffee is a brewed drink prepared from roasted seeds, commonly called coffee beans, of the Coffea. Caffeinated coffee has a stimulating effect in humans....
, walnuts, peanut

Peanut

The peanut, or groundnut , is a species in the legume Fabaceae native to South America, Mexico and Central America. It is an annual plant herbaceous plant growing to 30 to 50 cm tall....
s, borojo, pomegranates, yerba mate

Yerba mate

Yerba mate , Ilex paraguariensis, is a species of holly native to subtropical South America in Argentina, southern Chile, eastern Paraguay, western Uruguay and southern Brazil....
, and other 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.

High levels of polyphenols can generally be found in the fruit skins.

Health benefits

Polyphenols were once briefly known as Vitamin P. The possible health benefits of specific polyphenols such as Quercetin

Quercetin

Quercetin is a plant-derived flavonoid, specifically a flavonol, used as a nutritional supplement.The American Cancer Society says that quercetin "has been promoted as being effective against a wide variety of diseases, including cancer....
are well-established, and there are less well-established claims of health benefits from all types of polyphenols.

Research indicates that polyphenols may have 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....
characteristics with potential health benefits. They may reduce the risk of cardiovascular disease and cancer. Polyphenols have also been investigated as a source of additional health benefit in organic produce, but no conclusion was made. Polyphenols bind with nonheme iron (e.g. from plant sources) in vitro in model systems. This may decrease its absorption by the body.

Polyphenol

Chemistry

Classification and Nomenclature

In Foods

Health benefits

See also

External links