Lawsone
Encyclopedia
Lawsone 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 balsamina). Humans have used henna extracts containing lawsone as hair and skin pigment
s 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
sunscreen
s. Chemically, lawsone is similar to juglone
, which is found in walnuts.
Dye
A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and requires a mordant to improve the fastness of the dye on the fiber....
present in the leaves of the henna
Henna
Henna is a flowering plant used since antiquity to dye skin, hair, fingernails, leather and wool. The name is also used for dye preparations derived from the plant, and for the art of temporary tattooing based on those dyes...
plant (Lawsonia inermis) as well as jewelweed (Impatiens balsamina). Humans have used henna extracts containing lawsone as hair and skin pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
s for more than 5000 years. Lawsone reacts chemically with the protein keratin
Keratin
Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...
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
Sunless tanning
Sunless tanning Sunless tanning Sunless tanning (also known as UV-free tanning, self tanning, spray tanning (when applied topical, or fake tanning) refers to the application of chemicals to the skin to produce an effect similar in appearance to a suntan...
sunscreen
Sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...
s. Chemically, lawsone is similar to juglone
Juglone
Juglone, also called 5-hydroxy-1,4-naphthalenedione or 5-hydroxynaphthoquinone, is an organic compound with the molecular formula C10H6O3. In the food industry, juglone is also known as C.I. Natural Brown 7 and C.I. 75500...
, which is found in walnuts.