出典:Wiktionary
From Lawsonia, (Lawsonia inermis).
lawsone (uncountable)
出典:Wikipedia
出典:『Wikipedia』 (2011/07/14 18:06 UTC 版)
Lawsone (2-hydroxy-1,4-naphthoquinone), also known as hennotannic acid, is a red-orange dye present in the leaves of the henna plant (Lawsonia inermis) as well as jewelweed (Impatiens balsamica). Humans have used henna extracts containing lawsone as hair and skin pigments for more than 5000 years. Lawsone reacts chemically with the protein keratin in skin and hair, in a process known as Michael addition, resulting in a strong permanent stain that lasts until the skin or hair is shed. Lawsone strongly absorbs UV light, and aqueous extracts can be effective sunless tanning sunscreens. Chemically, lawsone is similar to juglone, which is found in walnuts.