Urushiol
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225242161
2008-07-12T17:25:55Z
Philistineembassy
7465636
:''For information on urushiol poisoning, see '''[[Urushiol-induced contact dermatitis]]'''.''
'''Urushiol''' ({{pronEng|ʊˈruːʃiɒl}}) is an oil found in [[plants]] of the [[Linnaean taxonomy|Family]] [[Anacardiaceae]], especially ''[[Toxicodendron]]'' ''spp.'' (''e.g.'' [[poison oak]], [[poison ivy]], and [[poison sumac]]). It is also found in the nut shell of [[cashew]] [[fruit]] (''Anacardium occidentale'') and in mango sap and the skin of the [[mango]] [[fruit]]{{Fact|date=July 2008}}. Breaking the vine of a green mango fruit produces a fine aerosol of sap that causes severe reactions in previously sensitized individuals. It causes an allergic [[skin]] rash on contact, known as [[urushiol-induced contact dermatitis]]. The name comes from the [[Japanese language|Japanese]] word ''urushi'', which denotes a [[lacquer]] produced in [[East Asia]] from the sap of ''kiurushi'' trees (''[[Toxicodendron vernicifluum|Lacquer Tree]]''). The oxidation and polymerization of urushiol in the tree's sap in the presence of moisture allows it to form a hard lacquer, which is used to produce traditional Chinese and Japanese lacquerwares.
Urushiol is a yellow liquid with a boiling point of 200-210 °C. It is [[miscible]] in alcohol and ether, but nearly immiscible in water. Chemically, urushiol is a mixture of several closely related [[organic compound]]s. Each consists of a [[catechol]] substituted with an [[alkyl]] chain that has 15 or 17 carbon atoms. The alkyl group may be [[Saturation (chemistry)|saturated]] or unsaturated; urushiol oil is a mixture of saturated and unsaturated molecules. The exact mixture depends on the species of the plant. For example, poison oak urushiol contains mostly catechols with C<sub>17</sub> side chains, but poison ivy and poison sumac contain mostly catechols with C<sub>15</sub> side chains. The allergic reaction is dependent on the degree of unsaturation of the [[alkyl]] chain. Less than half of the general population reacts with the saturated urushiol alone, but over 90% react with urushiol containing at least two degrees of unsaturation (double bonds).
{| align = "center"
|[[Image:Urushiol.svg|100px]]
|R = (CH<sub>2</sub>)<sub>14</sub>CH<sub>3</sub> or<br>R = (CH<sub>2</sub>)<sub>7</sub>CH=CH(CH<sub>2</sub>)<sub>5</sub>CH<sub>3</sub> or<br>R = (CH<sub>2</sub>)<sub>7</sub>CH=CHCH<sub>2</sub>CH=CH(CH<sub>2</sub>)<sub>2</sub>CH<sub>3</sub> or<br>R = (CH<sub>2</sub>)<sub>7</sub>CH=CHCH<sub>2</sub>CH=CHCH=CHCH<sub>3</sub> or<br>R = (CH<sub>2</sub>)<sub>7</sub>CH=CHCH<sub>2</sub>CH=CHCH<sub>2</sub>CH=CH<sub>2</sub> and others
|}
==See also==
* [[Burow's solution]], for treating the toxin
* [[Bentoquatam]], a barrier creme
* [[Hapten]]
* [[Mango]]es, the skin
* [[Poison ivy]]
* [[Toxin]]
* [[Western Poison-oak]]
* [[Pistachio]]
* [[Cashew]]
* [[Anti-itch drug]]
* [[Anacardic acid]]
==External links==
*[http://waynesword.palomar.edu/ww0802.htm Poison Oak] at ''Wayne's Word''
*[http://www.cattail.nu/ivy/ivy_index.html The Poison Ivy Tutorial]
[[Category:Benzenediols]]
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