|WikiProject Biology||(Rated Start-class, Mid-importance)|
|WikiProject Chemicals||(Rated Start-class, Mid-importance)|
Could yous not use ONLINE STORES as REFERENCE ?
I added the cleanup tag because this page needs a rewrite, and I don't have the requisite knowledge. For instance, the second paragraph is one line, and the third paragraph is unclear in the "several thousand . . . " line. The article vascillates between using EGCg and EGCG to refer to a particular compound. (I don't know which is correct, of if they're interchangeable.) The conclusion discusses what would appear to be antimicrobial properties of catechin. The sole reference for this article also discusses these properties, but provides no reference of its own. Indeed, most of this article appears to have been directly plagiarized from the source. This is inexcusable.
update by my ip in the edit history 5/14/06 reference from a online store! is not a valid reference. so i removed, and replaced with a valid ref. link. and added some text, but someone should find reference for those magical antioxidant properties, im tired right now, and disecting this topic has been very time consuming.
this is a biochemistry subject, please treat it as such.
This article is poorly organized, and does not provide an adequate description of what a catechin is, or what the current scientific\medical opinion about it's effects is. It is almost entirely lacking in citations, and only one of these appears to be a sufficiently rigorous source. I attempted to find some more reliable information, but I am not familiar enough with the subject to write a better article. 18.104.22.168 05:55, 11 June 2006 (UTC)
Latercomer to this article
i havent been involved in creating this article or developing its text, but i have started to try to add citations and rewrite as needed. much of the material seems valid, but sourcing will take some time. cheers Covalent 21:01, 12 June 2006 (UTC)
"Dictionary.com: Catechin; A crystalline substance, C15H14O6, derived from catechu and used in tanning and dyeing. Also called catechol."
Catechol: A biologically important organic phenol, having two hydroxyl groups attached to the benzene ring.
Phenol: A caustic, poisonous, white crystalline compound, C6H5OH, derived from benzene and used in resins, plastics, and pharmaceuticals and in dilute form as a disinfectant and antiseptic. Also called carbolic acid. Any of a class of aromatic organic compounds having at least one hydroxyl group attached directly to the benzene ring."
I think this supports the theory that catechins have antimicrobial properties. At least we know it's not a protein, and rather a crystalline substance. But a phenol can also be an "aromatic organic compound." I'm sorry, I don't have much knowledge of the subject as a whole, but is there any way to tell which type of phenol the catechins from Green/White tea are?
- In case you are not familiar with organic chemistry, the two definitions of "phenol" are not mutually exclusive--the first is specific and the second is general:
- Phenol as a specific compound, is C6H5OH, which is basically a benzene ring with one of the hydrogen atoms replaced by a hydroxyl group, and has the properties listed above.
- Phenols as a general class of compounds are structurally similar to phenol-- they must have at least one hydroxyl group attached directly to the benzene ring. Note that "aromatic" means "containing a benzene ring".
- With that in mind, I think it's pretty clear that catechins are of the general type of phenol, not the specific compound called phenol.
- Structural similarity often implies similar properties, but the fact that phenol is used as an antiseptic does not mean that catechins are antimicrobial just because they are phenols. They might be, but more evidence is needed. You might as well say that wood alcohol is good to drink because it's an alcohol!
- Catechins are definitely not proteins. Proteins are made up of amino acids (i.e. containing NH2). However, as far as I can tell, the article (at least the current version) does not claim that catechins are proteins.
- --MAzari 02:40, 10 August 2006 (UTC)
I think the retention time under Spectral Data/UV-Vis should be removed. As an analytical chemist I know that retention time varies tremendously under different instrument conditions, even different instruments. This data is too narrow, not useful, and misleading.
- --achemist4u 11:00, 12 August 2011
Comment/Question for Authors/Editors:
The article mentions bacteria as being a type of protein. I'm not an expert but this does not seem right. Bacteria are living entities. Proteins, as such, are not living. --CalumetK.
- Bacteria produce toxins. The toxins are proteins. The current wording is confusing, and that sentence should be re-written.
- --MAzari 02:44, 10 August 2006 (UTC)
I have no expertise in this area and don't want to mess with the article, but I found catechin as an herbicide produced (in two isomers) by spotted knapweed. It was touted as a candidate for commercial application, but I have found no products. Fairandbalanced 16:53, 15 September 2007 (UTC)
Links to other articles:
Hi, the first question that occurred to me when reading this article is why is it called "catechin". So I looked it up in the dictionary and found that it is related to the Catechu plant and other substances derived from it, such as pyrocatechol. I think it would be interesting to relate these to catechin, even though tea is more popular.
- Done. MatthewEHarbowy 18:11, 15 December 2006 (UTC)
Catechin is the proper name for this class of compounds. That said if it relates then it would be nice to see. Jasoninkid 22:59, 31 May 2007 (UTC)
"What is a catechin?"
I noticed the editor mentioning there is insufficient data to provide an adequate description of what exactly a catechin is.
"Catechins belong to the flavan-3-ol class of flavonoids and these are found in green tea leaves. . There are 4 major catechins in green tea leaves, namely (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epicatechin (EC), all polyphenolic compounds."
Polyphenolic compounds are "any of a large group of plant substances that include the anthocyanins."
Anthocyanins are the various water-soluble pigments that are found in flowers and other plants, ranging from violet, blue, to many shades of red.
There you have it... a catechin is the pigmentation created by the plant, I believe during photosynthesis.... Though why it would be a different pigment than green, perhaps the biosynthesis process, I don't know. I'll edit if I think up of anything else.
I'm fairly sure, as someone else mentioned, that catechins are not proteins. I believe this because simple biology tells us that chlorophyll is a pigment, yet it is not a protein. I believe these catechins are a different kind of pigment, created by the plants, to either hue a certain flower petal, or leaf, to aid in either reproduction or as a self-defense mechanism. (Camouflage)
Sorry, I dont have a MD in biochemistry, but I believe my info is up-to-date :)
The role of a catechin is not known, polyphenolic compounds are compounds that have 2 or more phenol groups (an OH on a benzing ring. Anthocyanins are similar to but not the same as catechins. You are right that it is not a protein, at the most basic level proteins are made of amino acids and catichins are not, it is best described as a small molecule.
Also would people pleases sine their posts! Jasoninkid 22:57, 31 May 2007 (UTC)
Decay after brewing?
My sister learned in school that catechins in tea decay/deteriorate after 24-48 hours. Can anyone confirm this?
Yes they do and in much less time. Jasoninkid 22:48, 31 May 2007 (UTC)
Catechin Temperature Decomposition
This Article reads: "Heating catechin past its point of decomposition releases pyrocatechol, which explains the common origin of the names of these compounds."
- Pyrolysis of catechin begins above it's melting point, approx 200 degrees C, and the principal products of pyrolysis are catehin and 4-methylcatechin at 500C (see, e.g., Ohara et al, Structure Elucidation of Condensed Tannins, Holzforshung 57 (2003) 145-149.) MatthewEHarbowy 21:45, 9 May 2007 (UTC)
My experience has suggest that they will discompose at any temp if in solution with the rate being personal to temp. Jasoninkid 22:51, 31 May 2007 (UTC)
Chocolate / Cocoa
I'm not sure what the norm is for articles with titles of scientific origin, but would it be possible to include an IPA pronunciation (or, more likely, a couple of common pronunciations) of "catechin" at the beginning of the article? ----22.214.171.124 (talk) 21:03, 6 January 2010 (UTC)
Infobox - LD50: oral? Chemistry - catechin numbered: most of the numbers are missing. It would be better to say it has 4 stereoisomers. "activating the double bond on ring C"? What double bond? Biosynthesis : The shikimate pathway is not involved in converting phenylalanine to hydroxycinnamoyl CoA. The step from hydroxycinnamic acid to hydroxycinnamoyl CoA is not mentioned. Wouldn't E5 be dihydroflavaNOnol 4-reductase? Interactions with human genes - CYP1A1: implied should be implicated. S100B: It isn't an enzyme. This states twice that catechin decreases expression. "oxidative stress, are in agreement": "are" should be deleted. Candidate therapeutic protective for HIV-associated neurocognitive disorders: "and caused by" - delete "and". Suppression heat-induced pain: Suppression of. Ecological effects: should be a ; after behavior. Ref. 5 & 26 are missing a space. Ref. 31: The P of P450 is always upper case. Ref. 52 appears to be truncated. 126.96.36.199 (talk) 04:39, 27 September 2014 (UTC)