Talk:Urushiol

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Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 12:11, 17 January 2022 (UTC)

Van der Waals

This bit doesn't actually make sense to me as worded. Saturated side chains will be straighter and side chains with a double bond will be 'kinked'. That kink usually means the side chains will pack less effectively to each other. Normally we think about the binding of a molecule to a pharmacophore or a known other molecule. I know nothing about this molecule, but it sounds like unsaturated side chains bind better to something (known or unknown) which makes them worse. (I would expect unsaturated side chains to bond less well to each other. I think that is not what the author is talking about but the wording is odd so it is possible). I am having difficulty expressing what feels off about the statement because it is true, but strange. Van der Waals forces are responsible for nearly all of what different drugs and biological molecules do and what shape they have. It is like saying: "Gravity is responsible for 'class M stars'". It's true, but oddly over specific from one point of view and incredibly vague from another point of view. — Preceding unsigned comment added by 128.91.197.39 (talk) 19:38, 1 January 2014 (UTC)

Time to degrade urushiol

How long does urushiol take to degrade to a non-allergenic form once it is manufactured by the plant?—Preceding unsigned comment added by 69.105.41.90 (talk • contribs) 00:25, 24 September 2006

There is anecdotal evidence that hand tools contaminated with urushiol can still induce dermatitis a year after they have been used to cut or dig out urushiol-bearing plants, and that parts of dead plants can remain toxic one to five years, and longer, but I am not aware of any formal studies. Some information is available in this archived Michigan State University Extension article. — Quicksilver^{T @} 19:34, 8 April 2015 (UTC)

Urushiol and mango

The rumor that urushiol can be found in the "mango sap and the skin of a mango fruit" comes from this case http://content.nejm.org/cgi/content/extract/339/4/235, however said source only states that "the sap of the mango ring contains oleoresins that cross-react with the oleoresins of poison ivy", so whether mango literally contains urushiol is still up for question. Until someone can properly back up the claim, I'm removing the following statement from the article:

"It is also found in the nut shell of cashew fruit (Anacardium occidentale) and in mango sap and the skin of the mango fruit[citation needed]. Breaking the vine of a green mango fruit produces a fine aerosol of sap that causes severe reactions in previously sensitized individuals."

--Waxsin (talk) 18:03, 2 January 2009 (UTC)

Supposedly the offending chemical (which is related to urushiol) is in the skin of the mango, according to Dr. Doris Day, appearing on ABC Good Morning America Health on Tuesday April 27, 2010.--Filll (talk | wpc) 18:43, 28 April 2010 (UTC)

My wife had a first hand experience wwhile staying in the Phillipines during the summer of 2012. Her and some friends ate Mango fruit without peeling the skin. Some of them formed a rash similar to that of poison oak. Since the SFDA does place the mango in the same family, I think it is safe to say the oil can be found on the peel of the fruit. Though the variety of the mango may be in question. — Preceding unsigned comment added by 132.190.92.85 (talk) 20:38, 16 October 2013 (UTC)

You guys are idiots. It's not speculation, it's a fact. It isn't up for debate. You can keep removing it, but there are plenty of resources to point out the stone cold fact that mango peels contain urushiol:

Atlas of Immunology http://books.google.com/books?id=L4CI-qkhuQ8C&pg=PA375&dq=mango+urushiol&hl=en&sa=X&ei=xhNxU9-KOsOyyATT7IKoCw&ved=0CDsQ6AEwAg#v=onepage&q=mango%20urushiol&f=false

American College of Allergy, Asthma and Immunology http://www.acaai.org/allergist/Resources/ask-allergist/Pages/Poison_Ivy_Mango.aspx

United States National Library of Medicine http://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+7485

Honolulu Star-Bulletin http://www.nutritionatc.hawaii.edu/HO/2005/309.htm

Livestrong http://www.livestrong.com/article/179501-mango-skin-rashes/

Fisher's Contact Dermatitis http://books.google.com/books?id=dQBAzfyCeQ8C&pg=PA407&dq=mango+urushiol&hl=en&sa=X&ei=xhNxU9-KOsOyyATT7IKoCw&ved=0CC0Q6AEwAA#v=onepage&q=mango%20urushiol&f=false

If you cannot contest these sources, please add mangos to the list. — Preceding unsigned comment added by 68.193.205.214 (talk) 18:35, 12 May 2014 (UTC)

Urushiol in Mangos

Is there really truly any Urushiol in Mangos? If so, in which parts? What is your proof/evidence?

The "Potential for contact dermatitis" section of the Mango article is a confusing mess! This sentence is particularly confusing: "Urushiol is also present in mango leaves and stems." What is the word "also" doing in this sentence? What is the reliable source -- how do we know that Urushiol is in leaves/stems vs. other parts?

Having read everything readily available here, it is clear that various parts of mangos contain an oil which is Urushiol-like and that some poison-ivy sensitve people react to. It is completely unclear which parts, if any, actually contain Urushiol. It seems like a fair next step to remove any related claims about the presence of Urushiol from the Mango article, until someone comes forward with credible, specific sources? -96.233.24.251 (talk) 20:30, 18 May 2014 (UTC)

Purpose

Why do plants produce this stuff? It doesn't seem logical to me that every plant should produce so much of this stuff to bring a rash days after skin contact. If that was all urushiol did, plants would have an advantage if they made less of it. This article should mention its other purposes to plants. (I'm currently suffering from it) --74.227.112.249 (talk) 20:33, 7 June 2008 (UTC)

Evolutionary significance

"The evolutionary significance of poison oak resin containing urushiol is difficult to explain. The resinous sap probably helps to seal wounds and may retard the growth of infectious fungal and bacterial spores. A chemical defense strategy against "predatory pressure" seems unlikely since the foliage and fruits are eaten by deer, goats, horses, cattle and a variety of birds. In fact, wood rats even use the branches to construct their nests. Only humans appear to have painful encounters with the plant, although laboratory studies indicate sensitivity on exposed skin of guinea pigs, rabbits, mice, sheep, dogs and rhesus monkeys.

"In the case of humans, our well-developed immune system may be overreacting to a relatively innocuous plant resin on the skin. But there is a positive side to all of this--research on poison oak may lead to a better understanding of the human immune system and the treatment of renegade viruses and tumor cells. In the final analysis, poison oak may be a blessing in disguise." (Source: American Botanical Council Herbalgram Volume 34: 36-42, 1995 by W.P. Armstrong and W.L. Epstein, M.D. cited in http://waynesword.palomar.edu/ww0802.htm) -69.87.203.235 (talk) 18:58, 8 August 2008 (UTC)

Solubility and destructibility

The article currently says that urushiol is miscible in alcohol and ether, but nearly insoluble in water. Is a reference available for this claim? Unreferenced claims that urushiol is not soluble in alcohol are also present on the internet. Alcohol has both polar and nonpolar characteristics, allowing it to dissolve in water and many nonpolar liquids, e.g. hydrocarbons. Presumably it's the nonpolar property of alcohols that allow them to wash urushiol off of surfaces. How about detergents and detergent solutions? If that works to dissolve urushiol, it should be mentioned in the article.

I added a peer reviewed reference providing solubility. Wikfr (talk) 02:18, 9 December 2011 (UTC)

The article currently says nothing about what might destroy the urushiol molecules. Does ultraviolet light from sunlight have any effect? How about bleaching compounds, such as hydrogen peroxide or sodium hypochlorite (household bleach)? There are many articles on the Web that state that urushiol isn't destroyed by fire, so one must not attempt to burn plants containing the compounds, but this seems absurd. When plants such as poison oak and poison ivy are exposed to fire, most likely the urushiol is boiled off and carried away as a vapor in the smoke before it can be decomposed by the flame. There must be a temperature at which urushiol oxidizes into harmless compounds. Anyone?—Quicksilver^{T @} 23:19, 9 September 2010 (UTC)

"The urushiol liquid is an oleoresin contained within the sap of poison-ivy and related plants, and after injury the sap leaks to the surface of the plant where the urushiol becomes a blackish lacquer after contact with oxygen."

Is this oxidized form of urushiol allergenic? Some years ago I got contact dermatitis from agave juice droplets which splashed on my arms and legs while removing living plants with a saw and machete. However, I've noticed that I can handle dead, brown agave lobes with my bare hands, with no effect whatsoever. Is the same true of urushiol-containing plants after they've been dead a while, i.e., does the urushiol degrade into something non-allergenic? (The irritant in agaves is not urushiol, as far as I know. Agave juice contains oxalic acid, and maybe some other organic compounds that produce contact dermatitis. The initial dermatitis lasts 2-3 weeks, but the itching can go on for several years where the blisters were, presumably due to embedded needle-like oxalic acid crystals.)—Quicksilver^{T @} 17:51, 12 September 2010 (UTC)

The oil can persist even on dead tissue for some time. Hardyplants (talk) 20:47, 12 September 2010 (UTC)

Genus of mangos

...is Mangifera, not Toxicodendron. --178.197.227.196 (talk) 17:37, 24 May 2014 (UTC)

Boiling point

A boiling point of 200 °C at NORMAL pressure is impossible, it must be much higher. Thus, 200 °C is only possible at a very low pressure. --FK1954 (talk) 12:39, 7 November 2015 (UTC)

R group is not alkyl

EntangledSpins (talk) 13:39, 2 September 2016 (UTC) By definition an alkyl group is saturated. The R groups shown in the diagram are all alkenes and thus R should be described as alkenyl.

Andre Dufresnoy's claims of poison ivy treatment seem to be unsupported by modern medicine

In the history section there are two sentences talking about Andre Dufesnoy and his experiments with poison ivy treatment. The sentences claim that he came up with a "medicinal use" for Urushiol which "yielded several positive results". However, my cursory research on this subject has led me to believe that there are no modern medical uses for the oil. Is it then accurate to say he came up with one, and to take his results at face value? The source cited for these sentences uses slightly different language: it never credits Dufresnoy for coming up with a "medicanal use" of poison ivy, and it says that Durfesnoy "claimed" positive results, not "yielded". Another source makes it clear that poison ivy's efficacy as a treatment was claimed by many doctors in the 19th century, but then fell out of favor everywhere but homeopathy circles. The implication seems to be that modern medicine has never found any evidence it works.

I am not a frequent editor here, so am unsure what to change. I believe User:Leight.cassidy was the contributing editor. RampagingCarrot (talk) 23:47, 1 June 2020 (UTC)

I'm seeing the same thing. I'm going to go ahead and alter that passage, to be clear that he claimed results. 2604:6000:1506:D5A4:AD52:7199:756C:D7AA (talk) 21:40, 3 September 2020 (UTC)