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Author Topic: What are the pigments in Lawsonia alba?  (Read 5459 times)

Offline aysha

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What are the pigments in Lawsonia alba?
« on: 04/06/2009 05:57:47 »
what pigments are present in lawsonia alba(mehndi)which give colour?
« Last Edit: 10/06/2009 08:30:57 by chris »


 

Offline Bored chemist

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Re: What are the pigments in Lawsonia alba?
« Reply #1 on: 04/06/2009 07:09:27 »
If you want to look that up on the web you might want to search for "henna".
The dominant component that colours skin and hair is lawsone.
http://en.wikipedia.org/wiki/Lawsone
The plant itself is green and the source of that colour is, of course, chlorophyl.
 

Offline Yomi

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Re: What are the pigments in Lawsonia alba?
« Reply #2 on: 08/06/2009 07:32:00 »
The dye is traditionally found in India, Pakistan, Iran, and North Africa—as well as in expatriate communities from these countries. The application of henna to goat skin bags, after they have been salt-cured, is supposed to "insect-proof" or "moth-proof" the bags, by making the skin poisoned or inedible.
 

Offline Bored chemist

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Re: What are the pigments in Lawsonia alba?
« Reply #3 on: 08/06/2009 18:44:39 »
NP4M,
What does any of that have to do with answering the question?
 

Offline Madidus_Scientia

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Re: What are the pigments in Lawsonia alba?
« Reply #4 on: 09/06/2009 18:19:46 »
Also, when copying word for word from another website, you should give credit to the website.
 

Offline glovesforfoxes

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Re: What are the pigments in Lawsonia alba?
« Reply #5 on: 10/06/2009 08:11:49 »
Yeah, he's forgetting to do that a lot.
 

Offline aysha

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What are the pigments in Lawsonia alba?
« Reply #6 on: 11/06/2009 06:21:51 »
hoooo GOD. Actually i want to know about those pigments which colour the skin.
 

Offline Chemistry4me

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Offline Bored chemist

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What are the pigments in Lawsonia alba?
« Reply #8 on: 11/06/2009 19:14:34 »
Do you mean the melanin that naturally colours the skin or the reaction products of lawsone with the skin's proteins that give the colour to mehndi (and similar ones that are made when henna is used for dying hair)?

The first group are easy. the second ones are rather complicated mixtures of condensation products from the lawsone and (I think) mainly the lysine residues in the proteins.
The chemistry is similar to the mailard reaction.
http://en.wikipedia.org/wiki/Maillard_reaction
 

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What are the pigments in Lawsonia alba?
« Reply #8 on: 11/06/2009 19:14:34 »

 

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