Green tea extract: Difference between revisions
Content deleted Content added
→Biochemical properties: merged what was useful here to Green tea |
Christian75 (talk | contribs) {{R from merge}} |
||
| (4 intermediate revisions by 2 users not shown) | |||
| Line 1: | Line 1: | ||
#REDIRECT [[Green tea#Extracts]] |
|||
{{multiple issues| |
|||
{{medref|date=December 2012}} |
|||
{{Citation style|date=August 2009}} |
|||
}} |
|||
{{R from merge}} |
|||
A '''green tea extract''' is a herbal derivative from [[green tea]] leaves (''[[Camellia sinensis]]''). Containing [[polyphenol antioxidant|antioxidant]] ingredients – mainly green tea [[Tea catechins|catechins]] (GTC) – green tea and its derivatives are sometimes used as [[dietary supplement]]s and in [[alternative medicine]]. |
|||
== History of tea extracts == |
|||
Green tea extracts have been used in traditional [[traditional Chinese medicine|Chinese]] and Indian medicine for a variety of uses.<ref>{{cite web|title=Green tea|url=http://umm.edu/health/medical/altmed/herb/green-tea|website=Complementary and Alternative Medicine Guide|publisher=University of Maryland Medical Center|accessdate=3 May 2015}}</ref> |
|||
== Forms == |
|||
Green tea leaves are initially processed by soaking in an alcohol solution, which may be further concentrated to various levels; byproducts of the process are also packaged and used. Extracts may be sold in liquid, powder, capsule, or tablet form.<ref name=Johnson/> Decaffeinated versions are also available.<ref>{{cite web|title=Update on the USP Green Tea Extract Monograph|url=http://www.usp.org/usp-nf/notices/retired-compendial-notices/update-usp-green-tea-extract-monograph|publisher=USP|language=en|date=April 10, 2009}}</ref> |
|||
Green tea extract supplements are accessible over the counter in various forms. Standardized green tea extract is 90 percent total polyphenols, and 1 capsule equals 5 cups of tea.<ref>A.H. Pressman & S. Buff, The complete idiot's guide to vitamins and minerals, New York: New York Alpha Books, 1997, p. 283.</ref><ref>A. Bascom, Incorporating herbal medicine into clinical practice, Philadelphia: F.A. Davis Company, 2002, p. 153.</ref> |
|||
== Chemistry and biochemistry == |
|||
=== Constituents === |
|||
The cardinal antioxidative ingredient in the green tea extract is green tea catechins (GTC), which comprise four major epicatechin derivatives; namely, epicatechin (EC), [[epigallocatechin]] (EGC), [[epicatechin gallate]] (ECG), and [[epigallocatechin gallate]] (EGCG). Of which, EGCG accounts for more than 40% of the total content. |
|||
Other components include three kinds of [[flavonoid]]s, known as [[kaempferol]], [[quercetin]], and [[myricetin]].<ref>Committee on Diet, Nutrition, and Cancer, Assembly of Life Sciences, National Research Council, Diet, nutrition, and cancer, Washington: D.C National Academies Press, 1982, p. 286.</ref> A remarkably higher content of myricetin is detected in tea and its extracts than in many other plants, and this high concentration of myricetin may have some implications with the [[bioactivity]] of tea and its extracts.<ref name=Johnson/> |
|||
=== Chemical properties === |
|||
Green tea extract is approximately two times more antioxidant-active than [[Vitamin C]]. The main attribution is supposed to be EGCG.<ref>Comparison between vitamin C, green tea extracts and olive leaf extracts : Dr Stevenson, L,. et al. Oxygen Radical Absorbance Capacity (ORAC) Report on Olive Leaf Australia's Olive Leaf Extracts, Southern Cross University, 2005.</ref> |
|||
One study by the Drug and Food department of Iran in 2008 compared antioxidant properties of various green tea compounds with those of vitamin C and vitamin E: the study concluded that green tea extracts -for a total of approximately 68 mg of combined phenols, flavonoids and anthocyanidin present from 1g of a sample of "Chinas green tea" leaves, the grade yielding the highest content of bioactive chemicals- had the equivalent antioxidant power found in 50 mg-275 mg of vitamin C and 156 mg-813 mg of vitamin E <ref>"Determination Of Total Antioxidant Capacity Of Green Teas By The Ferric Reducing-Antioxidant Power Assay" by M. Hajimahmoodi,M. Hanifeh,M. R. Oveisi,N. Sadeghi,B. Jannat, (Drug and Food Control Department, Faculty of Pharmacy &Medical Sciences,University of Tehran, and Ministry of Health and Medical Education, Tehran Iran), published in "Iran. J. Environ. Health. Sci. Eng., 2008, Vol. 5, No. 3, pp. 167-172" , website: http://journals.tums.ac.ir/upload_files/pdf/_/8255.pdf "</ref> |
|||
== References == |
|||
{{reflist|2}} |
|||
[[Category:Green tea]] |
|||
[[Category:Polyphenol-enriched extracts]] |
|||
Latest revision as of 12:42, 10 October 2021
Redirect to:
- From a merge: This is a redirect from a page that was merged into another page. This redirect was kept in order to preserve the edit history of this page after its content was merged into the content of the target page. Please do not remove the tag that generates this text (unless the need to recreate content on this page has been demonstrated) or delete this page.
- For redirects with substantive page histories that did not result from page merges use {{R with history}} instead.