Catechins are polyphenolic antioxidant plant metabolites. They belong to the family of flavonoids and the subgroup flavan-3-ols (or simply flavanols).
The name of the catechin chemical family derives from catechu which is the juice or boiled extract of Mimosa catechu (Acacia catechu L.f).
Sources of catechins
Catechins constitute about 25% of the dry weight of fresh tea leaf, 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.
Catechins are also present in the human diet in chocolate, fruits, vegetables and wine and are found in many other plant species.
Epigallocatechin gallate is the most abundant catechin in tea.
Another stereoisomer, (-)-catechin, is released from the roots of the invasive weed, spotted knapweed. It acts as an herbicide to inhibit competition by a wide range of other plant species. This phytotoxic compound inhibits seed germination and growth.
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. Reduction in carcinogene
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sis was seen in vitro.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.
According to one researcher epigallocatechin-3-gallate is an antioxidant that helps protect the skin from UV radiation-induced damage and tumor formation.
Antibiotic effects
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.
DNA protection
Catechins, when combined with habitual exercise, have been shown to delay some forms of aging. Mice fed catechins showed decreased levels of aging. Oxidative stress was lowered in cell mitochondria, as well as increase in mRNA transcription of mitochondrial-related proteins.
Possible reduced benefits in treated chocolate
An editorial in The Lancet medical journal warned against increasing one’s intake of dark chocolate in order to improve health because the beneficial compounds are sometimes removed due to their bitter taste without an indication on the label. Additionally, such product may also be high in fat, sugar, and calories which can increase the risk for heart disease.
Anti-carcinogenic effects
In 2008 UCLA cancer researchers found that study participants who ate foods containing certain flavonoids seemed to be protected from developing lung cancer. Dr. Zhang, (professor of public health and epidemiology at the UCLA School of Public Health) said the flavonoids that appeared to be the most protective included catechin, found in strawberries and green and black teas; kaempferol, found in Brussels sprouts and apples; and quercetin, found in beans, onions and apples.
MAO effects
Catechin and epicatechin are also selective monoamine oxidase inhibitors (MAOIs) of type MAO-B.
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