Catechin
From Wikipedia, the free encyclopedia
Catechins are polyphenolic antioxidant plant metabolites, specifically flavonoids called flavan-3-ols. Although present in numerous plant species, the largest source in the human diet is from various teas derived from the plant Camellia Sinensis.
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[edit] Catechin, Epicatechin, Epigallocatechin, and the Gallates
Catechin and epicatechin are diastereomers, with (-)epicatechin and (+)catechin being the most common optical isomers found in nature. Catechin was first isolated from Acacia 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.
Epigallocatechin contains an additional phenolic hydroxyl group when compared to epicatechin, similar to the difference between pyrocatechol and pyrogallol.
Catechin gallates are gallic acid esters of the catechins; such as EGCG (epigallocatechin gallate), which is commonly the most abundant catechin in tea.
[edit] 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 .
Catechins are also present in the human diet in chocolate[2], from fruits and vegetables and wine[3]; and are found in many other plant species[4].
[edit] References
- ^ 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
- ^ Hammerstone JF, Lazarus SA, Schmitz HH Procyanidin content and variation in some commonly consumed foods. J Nutr, 130, 2086S–2092S (2000)
- ^ 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
- ^ The Flavonoids ed. JB Harborne, TJ Mabry, and H Mabry (1975)
