|MadSci Network: General Biology|
Hello Atul, I have found answers to your questions about henna. As you know henna does not permanently dye skin. What happens chemically is that lawsone (http://www.sigma-aldrich.com/sacatalog.nsf/StructForm?OpenForm&ParentUNID= 86256 8A3006B3723862568A2008041C4), the chemically active agent in henna will oxidize a component of the skin. This oxidation leads to a change in the color of the skin's pigment. The reason why henna staining only lasts several weeks is that eventually the skin cells die and slough off. As for your second question regarding isolation of the chemical responsible for the staining, it is possible to extract it. A crude water/ethanol extract of henna leaves contains the lawsone and the rest of the plant material. The lawsone itself can then be extracted by mixing the plant material with either butanol or chloroform. This will give a more pure samle of the active ingredient. The reference I used to determine this is: http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed& list_uid s=8966192&dopt=Abstract Good luck! -Sarah Tegen
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