Talk:Catechin

message: Forgive my ignorance if this is wrong, but it looks like in PubChem and other sources that (+)-catechin and (--)-epicatechin should have the two hydroxyls in the B ring attached to 3' and 4' carbons, not 4' and 5' as it is currently depicted in the (+)-catechin article. Can any chemists out there confirm and fix the structure? Or let me know and I could fix and paste a corrected structure. Or explain why I'm wrong, would love to know.
Eric Yarnell (talk) 21:00, 7 January 2018 (UTC)
thread_title:  Chemical structure problem 

message: 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. 70.162.14.102 05:55, 11 June 2006 (UTC)
thread_title:  Cleanup Tag 

message: 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)
thread_title: Comment/Question for Authors/Editors:

message: 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)
thread_title: Links to other articles:

message: 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)
thread_title:  "What is a catechin?" 

message: 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)
thread_title:  Decay after brewing? 

message: This Article reads:
"Heating catechin past its point of decomposition releases pyrocatechol, which explains the common origin of the names of these compounds."
What is the temperature of decomposition? —The preceding unsigned comment was added by 67.79.200.162 (talk) 14:55, 9 May 2007 (UTC)
replies: text: 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, <I>Structure Elucidation of Condensed Tannins</i>, Holzforshung 57 (2003) 145-149.) MatthewEHarbowy 21:45, 9 May 2007 (UTC)
thread_title:  Catechin Temperature Decomposition 

message: Is Catechin only present in chocolate or also in low fat cocoa? --91.15.72.16 (talk) 12:22, 14 August 2008 (UTC)
thread_title:  Chocolate / Cocoa 

message: 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? ----72.207.255.52 (talk) 21:03, 6 January 2010 (UTC)
thread_title:  Pronunciation? 

message: 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.
69.72.92.28 (talk) 04:39, 27 September 2014 (UTC)
thread_title:  various problems 

message: This is the article in question: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2265593/
The portion dealing with catechin is in regard to compounds 12-15 (the four isomers of catechin) and their collective activities as opiate receptor antagonists.  The exception is (-)-catechin (compound 13) which had "weak partial agonist activity (Emax = 18% of U69,593)."  U69,593 is according to it's own wiki article "a potent and selective" kappa 1 receptor agonist.
I'm having problems editing this on my tablet (keeps crashing Firefox).  I will try and revisit this, however if someone else feels like adding the info feel free.
In my opinion the information is relevant here under the bioactivity studies sub heading with it's own sub heading "Interactions with human opiate receptors in vitro".  This way it matches the previous sub heading "Interactions with human genes in vitro".  Does anyone agree/disagree with this?
Any reasons for or against including this information in the article?  I know that my save earlier was incomplete and had issues.  I was trying to change modes to fix it, and it was deleted in the interim.  Apologies for that.
Thanks and cheers!
Dogtoy (talk) 23:25, 20 May 2016 (UTC)
replies: text: Reading through that article, Dogtoy, I vote that the whole section under Bioactivity be removed. The studies and article content are highly preliminary as early-stage lab research and esoteric for the majority of encyclopedia users. The extensive list under "Detail for all tested genes" should be removed as WP:IINFO. These studies are years/decades from being relevant to human physiology or medicine. The study you wish to add is similar as an early-stage in vitro receptor analysis not yet confirmed by other in vitro or in vivo work, therefore WP:PRIMARY. I suggest this information is not encyclopedic per WP:NOTJOURNAL and WP:NOTCRYSTAL; its inference for relevance to humans is not supportable by WP:MEDRS. --Zefr (talk) 02:11, 21 May 2016 (UTC)
replies: text: I can understand this point of view, Zefr.  I was thinking that the article which I referenced is relevant based upon using the gene interaction section as a model.  Would it be acceptable to include something along the lines of, "Preliminary in vitro testing suggests possible interactions with human genes (ref) and opiate receptors (ref)."  Just as a short footnote without listing all of the details which would be boring to the average wiki reader?  That way people who are interested in that info can read the reference papers for more info and it doesn't clutter the page.  What do you think?  Dogtoy (talk) 12:07, 21 May 2016 (UTC)

text: Would this be frowned upon because of WP:PRIMARY?  Thanks for the help and input btw.  Cheers! Dogtoy (talk) 12:14, 21 May 2016 (UTC)
replies: text: While I respect the science, I maintain this early-stage information about gene models is not encyclopedic and is at the lowest level of evidence quality. By WP:NOTEVERYTHING, we do not need to write into articles all information about the topic. But that is just my interpretation, so we can wait to see if other editors get into the conversation. Thanks for the reply. --Zefr (talk) 15:52, 21 May 2016 (UTC)
thread_title:  Trying to add info about in vitro receptor activity from journal article 

message: I moved the section below from the article because it is WP:PRIMARY in vitro research alluding to a possibility for in vivo effect. As we are writing an encyclopedia, not a textbook WP:NOTTEXTBOOK, this type of highly preliminary detail does not add substance to the article, but rather is a tangential highly speculative discussion far from proof of human relevance, and so is WP:UNDUE. We can discuss it here. --Zefr (talk) 14:17, 25 July 2016 (UTC)
thread_title: Human gene research in vitro

message: Zefr - I disagree with the removal of the history section. The sources are readily available in any library, and as far as I understand, Wikipedia does not require English language sources. In my opinion, it is very relevant that catechin-containing preparations have been used for a considerable amount of time and that research into the purported beneficial effect are nothing new (e.g. the claim that they might be even Vitamins). The use as drug 'catergen' is also relevant - after all, "catergen" was a licensed drug at least in Switzerland and Germany, and the side effects included fatalities. This information might be appropriate in a different section - but as the drugs are not currently in use (they are available as slimming drugs though), I think it is best suited for the  "history" section.
Ggux (talk) 20:04, 25 July 2016 (UTC)
replies: text: The content and references you provided do not impress as having significance to the current interests about catechins, leading to over-emphasis as WP:UNDUE. The emphasis you wish to make is not readily verifiable for English users of the encyclopedia. It's possible other editors may agree with you, but to reinstate the History section as you wrote it, WP:CON is needed per WP:ONUS. --Zefr (talk) 21:27, 25 July 2016 (UTC)
replies: text:  I think the historic use of a compound (or class thereof) such as catechins is very relevant for an encyclopedia, especially as it is not really something that is disputed. The current interest focuses on potentially beneficial effects, but this does not mean that adverse effects should be ignored - those drugs might not have been available in other countries, but there is a considerable amount of literature showing the effect (and potential mechanisms). What is the process to achieve WP:CON?Ggux (talk) 22:18, 25 July 2016 (UTC)
replies: text: Editors wishing to engage in this discussion about catechins will come here for comments. You can invite editors who have been part of the article's history, or can initiate dispute resolution per WP:DR. --Zefr (talk) 22:47, 25 July 2016 (UTC)
replies: text: Why do you object to historical data - it was part of the article before I made my edits, although the information was very limited. If I understood the reason for your decision, it would be easier to find a solution. Ggux (talk) 23:03, 25 July 2016 (UTC)
replies: text: I don't object to relevant historical information that affects why catechins are of interest today. The response I gave in the 2nd paragraph above summarizes my view about the content and sources you chose to add. --Zefr (talk) 23:12, 25 July 2016 (UTC)
replies: text:  I respectfully disagree. The historic (pre 1940s) references are mainly in German/Latin due to the nature of research - but I still believe that a brief paragraph on historical uses is appropriate for an encyclopaedia article, especially for a compound that does have such a long history of medicinal use. The information could of course also be included in other sections regarding the physiological effects - but I'm not sure whether this would be much better. Ggux (talk) 23:21, 25 July 2016 (UTC)
thread_title: History

message: Zefr - why did you remove the reference to immune function? This is very well documented and the reference used is not a primary source but a review article. It is relevant and the information is used for example in the toxicological assessment of phenolic compounds. I appreciate that we disagree about the inclusion of historic data - but the ability of catechin to cause haemolytic anaemia via auto-antibodies is neither a historic remark nor irrelevant. I'm happy to provide more details about this if necessary - but a paragraph on catechin-bioactivity should include these effects as well. Ggux (talk) 22:28, 26 July 2016 (UTC)
replies: text: The reference has to comply with source quality described in WP:MEDRS. Please read this, as it will clarify your choice of sources in the future when pertaining to human health or disease. --Zefr (talk) 22:37, 26 July 2016 (UTC)
replies: text:  Having read WP:MEDRS, I fail to see how "Martinez SE; Davies NM; Reynolds JK (2013). "Toxicology and Safety of Flavonoids". Methods of Analysis, Preclinical and Clinical Pharmacokinetics, Safety, and Toxicology. John Wiley & Son. p. 257. ." could not be seen as a reliable source. It is a medical textbook and includes numerous references to primary sources. Ggux (talk) 22:59, 26 July 2016 (UTC)
replies: text: For this type of content you wanted to add: "Catechin and its metabolites can bind tightly to red blood cells and thereby induce the development of Autoantibody, resulting in haemolytic anaemia and renal failure", you would need a systematic review of high-quality controlled trials to support statement of an effect on immune functions. No such work has been done. --Zefr (talk) 23:58, 26 July 2016 (UTC)
replies: text: That is not possible as there are no systematic reviews - but a sufficient number of case reports, primary studies etc. systematic reviews are not conducted for all biomedical questions - and applying this criterion correctly, you would probably have to remove 2/3 of the catechin article. A book chapter is in general a reasonably good review, and this one includes numerous references to primary sources. I will revise the statement to refer to the hepatoprotective drug and it's side effect - it is, in my opinion, extremely relevant.Ggux (talk) 06:48, 27 July 2016 (UTC)
thread_title: Immune function

message: Zefr - if I were to write and publish a systematic review on catechin, would this be a sufficient source to include here?Ggux (talk) 11:16, 27 July 2016 (UTC)
replies: text: WP:SELFPUBLISH; WP:MEDINDY. --Zefr (talk) 13:46, 27 July 2016 (UTC)
replies: text:   Zefr Ggux (talk) 14:03, 27 July 2016 (UTC)
replies: text: It is likely there are independent secondary sources adequate to represent the facts other than your own studies, so you should use them. Using your own research potentially leads to WP:SYNTH and WP:OR which are discouraged. As WP is an encyclopedia, not a textbook for writing your own research results, WP:5P1 applies, and for topics like catechin which partly fall under human health, medical references should comply with WP:MEDREV. --Zefr (talk) 14:38, 27 July 2016 (UTC)
replies: text: I understand the concept of focusing on secondary sources, but there simply aren't many for catechin. What makes for example the Linus-Pauling-Institute Website more reliable than a textbook on the safety of flavonoids? Based on this discussion, I think there is really the need for a proper review of catechins. But if I were to write such a review (and obviously publish it in an appropriate journal), wouldn't this be a very suitable source of information? After all, it would have been peer reviewed.  — Preceding unsigned comment added by Ggux (talk • contribs) 14:47, 27 July 2016 (UTC)
thread_title: Systematic review

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thread_title:  External links modified 

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message: *
*Gallic acid
:?
:....0mtwb9gd5wx (talk) 06:00, 30 October 2023 (UTC)
thread_title:  galloylated catechins