Journal ArticleDOI
Green tea composition, consumption, and polyphenol chemistry.
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TLDR
In addition to the normal complement of plant cell enzymes, tea leaf contains an active polyphenol oxidase which catalyzes the aerobic oxidation of the catechins when the leaf cell structure is disrupted during black tea manufacture as mentioned in this paper.About:
This article is published in Preventive Medicine.The article was published on 1992-05-01. It has received 1826 citations till now. The article focuses on the topics: Catechin & Theanine.read more
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Tea catechins and polyphenols: health effects, metabolism, and antioxidant functions.
Jane V. Higdon,Balz Frei +1 more
TL;DR: The effects of tea and green tea catechins on biomarker of oxidative stress, especially oxidative DNA damage, appear very promising in animal models, but data on biomarkers of in vivo oxidative stress in humans are limited.
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A Review of the Antioxidant Mechanisms of Polyphenol Compounds Related to Iron Binding
TL;DR: In this review, primary attention is given to the antioxidant (and prooxidant) activity of polyphenols arising from their interactions with iron both in vitro and in vivo.
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Inhibition of carcinogenesis by tea.
TL;DR: Tea has received a great deal of attention because tea polyphenols are strong antioxidants, and tea preparations have inhibitory activity against tumorigenesis, but epidemiological studies have not yielded clear conclusions concerning the protective effects of tea consumption against cancer formation in humans.
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Antioxidant Activity of Tea Polyphenols In Vivo: Evidence from Animal Studies
Balz Frei,Jane V. Higdon +1 more
TL;DR: Most promising are the consistent findings in animal models of skin, lung, colon, liver and pancreatic cancer that tea and tea polyphenol administration inhibit carcinogen-induced increases in the oxidized DNA base, 8-hydroxy-2'-deoxyguanosine.
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Dietary Flavonoids, Antioxidant Vitamins, and Incidence of Stroke: The Zutphen Study
TL;DR: In this paper, the hypothesis that dietary antioxidant vitamins and flavonoids account for this observation was investigated in a prospective study, where a cohort of 552 men aged 50 to 69 years was examined in 1970 and followed up for 15 years.
References
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Scavenging effect of extracts of green tea and natural antioxidants on active oxygen radicals
TL;DR: The results demonstrated that these antioxidants did not affect the respiratory burst of human polymorphonuclear leukocytes stimulated with PMA, and it was found that Rosemary antioxidants and Curcumin have weaker scavenging effects than Vc, but stronger thanVe.
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Tannins and Related Compounds. XC. : 8-C-Ascorbyl (-)-Epigallocatechin 3-O-Gallate and Novel Dimeric Flavan -3-ols, Oolonghomobisflavans A and B, from Oolong Tea. (3)
TL;DR: A chemical examination of the polypenolic constituents in commercial oolong tea has led to the isolation of a new-flavan-3-ol, two novel dimeric flavan-3ols named oolonghomobisflavans A and B, together with twenty-one known polyphenols including proanthocyanidins, hydrolyzable tannins and red pigments as discussed by the authors.
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Tannins and Related Compounds. LXIX. : Isolation and Structure Elucidation of B, B'-Linked Bisflavanoids, Theasinensins D-G and Oolongtheanin from Oolong Tea. (2)
TL;DR: In this paper, a chemical examination of the aqueous acetone extract of commercial oolong tea has led to the isolation of four new theasinensins D-G, and a new type of dimeric flavan-3-ol named oOLong-theanin.
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The purification and some properties of the polyphenol oxidase from tea (Camellia sinensis L.).
TL;DR: The kinetics of oxidation of most substrates are consistent with a mechanism in which oxidized and reduced forms of the enzyme form binary complexes with phenol and oxygen respectively, and a modified mechanism is postulated for the oxidation of chlorogenic acid.