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Encyclopedia > Catechin
Epicatechin (EC)
Epigallocatechin (EGC)

Catechins are polyphenolic antioxidant plant metabolites. They belong to the family of flavan-3-ols (which are not strictly speaking flavonoids since they have no carbonyl group). Although present in numerous plant species, the largest source in the human diet is from various teas derived from the tea-plant Camellia sinensis. Image File history File links Epicatechin. ... Image File history File links Epicatechin. ... Image File history File links Epigallocatechin. ... Image File history File links Epigallocatechin. ... Polyphenols are a group of chemical substances found in plants, characterized by the presence of more than one phenol unit or building block per molecule. ... Space-filling model of the antioxidant metabolite glutathione. ... For other uses, see Plant (disambiguation). ... Metabolites are the intermediates and products of metabolism. ... Flavonoids are a group of chemical compounds naturally found in certain fruits, vegetables, teas, wines, nuts, seeds, and roots. ... For other uses, see Tea (disambiguation). ... Binomial name (L.) Kuntze Camellia sinensis is the tea plant, the plant species whose leaves and leaf buds are used to produce tea. ...

Contents

Catechin, epicatechin, gallocatechin, epigallocatechin, and the gallates

Catechin and epicatechin are epimers, with (-)-epicatechin and (+)-catechin being the most common optical isomers found in nature. Catechin was first isolated from the plant extract catechu, from which it derives its name. Heating catechin past its point of decomposition releases pyrocatechol, which explains the common origin of the names of these compounds. In chemistry, an epimer is a stereoisomer that has a different configuration at only one of several stereogenic centers. ... In chemistry, isomers are molecules with the same chemical formula and often with the same kinds of bonds between atoms, but in which the atoms are arranged differently. ... Catechu is an extract of any of several species of Acacia—but especially Acacia catechu—produced by boiling the wood in water and evaporating the resulting brew. ...


Epigallocatechin and gallocatechin contain an additional phenolic hydroxyl group when compared to epicatechin and catechin, respectively, similar to the difference in pyrogallol compared to pyrocatechol. Hydroxide is a functional group consisting of oxygen and hydrogen: -O−H It has a charge of 1-. The term hydroxyl group is used when the functional group -OH is counted as a substituent of an organic compound. ... Pyrogallol or benzene-1,2,3-triol is a white crystalline powder and a powerful reducing agent. ... Pyrocatechol, more commonly known as catechol, is a benzenediol, with the formula C6H4(OH)2. ...


Catechin gallates are gallic acid esters of the catechins; such as EGCG (epigallocatechin gallate), which is commonly the most abundant catechin in tea. Chemical structure of 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. ... For other uses, see Ester (disambiguation). ... Epigallocatechin gallate (EGCG) is a type of catechin and is the most abundant catechin in tea. ...


Sources of catechins

Catechins constitute about 25% of the dry weight of fresh tea leaf[1], although total catechin content varies widely depending on clonal variation, growing location, seasonal/ light variation, and altitude. They are present in nearly all teas made from Camellia sinensis, including white tea, green tea, black tea and Oolong tea. It is also present in kratom, an obscure asian plant that has opiate activity. This article is about the beverage. ... Binomial name (L.) Kuntze Camellia sinensis is the tea plant, the plant species whose leaves and leaf buds are used to produce tea. ... Bai Hao Yinzhen from Fuding in Fujian Province, widely considered the best grade of white tea Bai Mu Dan, widely considered to be the second grade white tea White tea is tea made from new growth buds and young leaves of the plant Camellia sinensis. ... Green tea (绿茶) is tea that has undergone minimal oxidation during processing. ... Black tea Black tea is more oxidized than the green, oolong and white varieties; all four varieties are made from leaves of Camellia sinensis. ... Rolled Oolong tea leaves Oolong (Chinese: ; Pinyin: ) is a traditional Chinese tea somewhere between green and black in oxidation. ... Binomial name Korth. ...


Catechins are also present in the human diet in chocolate[2], fruits, vegetables and wine[3] and are found in many other plant species[4]. For other uses, see Chocolate (disambiguation). ...


Health benefits of catechins

The health benefits of catechins have been studied extensively in humans and in animal models. Reduction in atherosclerotic plaques was seen in animal models.[5] Reduction in carcinogenesis was seen in vitro.[6]


Many studies on health benefits have been linked to the catechin content. According to Norman Hollenberg, professor of medicine at Harvard Medical School, epicatechin can reduce the risk of four of the major health problems: stroke, heart failure, cancer and diabetes. He studied the Kuna people in Panama, who drink up to 40 cups of cocoa a week, and found that the prevalence of the "big four" is less than 10%. He believes that epicatechin should be considered essential to the diet and thus classed as a vitamin.[2]Science Daily March 12, 2007 Claims have been made regarding the health benefits of tea consumption since the beginning of its history 5,000 years ago. ... Harvard Medical School (HMS) is one of the graduate schools of Harvard University. ... KUNA-LP Channel 15 is a Telemundo affiliate in Indio-Palm Springs, CA. Also owned by KESQ-TV (ABC), KCWB (WB), and KDFX 33 (FOX) KUNA-LP signed on the air as K15EI on May 15, 1996 and switched to KUNA-LP on March 31, 2003. ...


According to one researcher[7] epigallocatechin-3-gallate is an antioxidant that helps protect the skin from UV radiation-induced damage and tumor formation.


Green tea catechins have also been shown to possess antibiotic properties due to their role in disrupting a specific stage of the bacterial DNA replication process.[8] White tea typically contains higher level of catechins. [9] Green tea (绿茶) is tea that has undergone minimal oxidation during processing. ... Bai Hao Yinzhen from Fuding in Fujian Province, widely considered the best grade of white tea Bai Mu Dan, widely considered to be the second grade white tea White tea is tea made from new growth buds and young leaves of the plant Camellia sinensis. ...


See also

Quercetin is a flavonoid that forms the backbone for many other flavonoids, including the citrus flavonoids rutin, hesperidin, naringin and tangeritin. ... Molecular structure of the flavone backbone (2-phenyl-1,4-benzopyrone) The term flavonoid refers to a class of plant secondary metabolites. ... Binomial name (L.) Kuntze Camellia sinensis is the tea plant, the plant species whose leaves and leaf buds are used to produce tea. ... For other uses, see Cocoa (disambiguation). ... A bottle of tannic acid. ... Polyphenols are a group of chemical substances found in plants, characterized by the presence of more than one phenol unit or building block per molecule. ...

References

  1. ^ Balentine DA, Harbowy ME and Graham HN, Tea: the Plant and its Manufacture; Chemistry and Consumption of the Beverage in Caffeine (1998), ed. G Spiller
  2. ^ Hammerstone JF, Lazarus SA, Schmitz HH Procyanidin content and variation in some commonly consumed foods. J Nutr, 130, 2086S–2092S (2000)
  3. ^ Ruidavets JB, Teissedre PL, Ferrieres J, Carando S, Bougard G, Cabanis JC (2000) Catechin in the Mediterranean diet : vegetable, fruit or wine? Atherosclerosis, 153, 101-117
  4. ^ The Flavonoids ed. JB Harborne, TJ Mabry, and H Mabry (1975)
  5. ^ "Differential effects of green tea-derived catechin on developing versus established atherosclerosis in apolipoprotein E-null mice" .  Circulation 2004 May 25;109(20):2448-53
  6. ^ "EGCG down-regulates telomerase in human breast carcinoma MCF-7 cells, leading to suppression of cell viability and induction of apoptosis" Int J Oncol. 2004 Mar;24(3):703-10
  7. ^ Santosh Katiyar, UAB associate professor of dermatology, J. Nutritional Biochemistry, May 2007
  8. ^ Helena Gradisar, Primoz Pristovsek, Andreja Plaper, Roman Jerala. Green tea catechins inhibit bacterial DNA gyrase by interaction with its ATP binding site. J Med Chem. 2007 Jan 25;50 (2):264-71
  9. ^ "New" white tea, surprisingly, may have a healthful edge. Environmental Nutrition. Sept 2003. FindArticles.com. 10 Dec. 2007. [1]

For other uses, see Caffeine (disambiguation). ...

External links


  Results from FactBites:
 
Catechin - Wikipedia, the free encyclopedia (488 words)
The concentration of catechins is higher in green and white tea.
Researchers believe that catechin is effective because it easily sticks to proteins, blocking bacteria from adhering to cell walls and disrupting their ability to destroy them.
Catechin reacts with toxins created by harmful bacteria (many of which belong to the protein family) and harmful metals such as lead, mercury, chrome, and cadmium.
Green Tea Catechins (2634 words)
Green tea catechins have been found to have a number of antioxidant activities, including scavenging of such reactive oxygen species as superoxide, hydroxyl and peroxyl radicals, inhibition of lipid peroxidation, inhibition of 2'-deoxyguanosine oxidation in DNA to 8-hydroxy-2' -deoxyguanosine and inhibition of the oxidation of low-density lipoproteins.
Green tea catechins have also been found to upregulate the synthesis of some hepatic phase II enzymes that are involved in the detoxication (detoxification) of some xenobiotics, including chemical carcinogens.
A recent human study indicates that the green tea catechins are mainly found in blood in the protein-rich fraction of plasma and in high-density lipoproteins.
  More results at FactBites »

 
 

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