Henna

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For the Bollywood film, see Henna (film).

iHenna

Lawsonia inermis

Scientific classification

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Myrtales
Family:	Lythraceae
Genus:	Lawsonia
Species:	Lawsonia inermis L.

Henna (Lawsonia inermis, syn. L. alba) is a flowering plant, the sole species in the genus Lawsonia in the family Lythraceae. It is native to tropical and subtropical regions of Africa, southern Asia and northern Australasia with an arid or at least seasonally dry climate.

It is a shrub growing to 6 m tall. The leaves are in opposite decussate pairs, oval, 2–4 cm long and 1.5–3 cm broad, with an entire margin and acute apex. The flowers are fragrant, produced in conical panicles 10–40 cm long, each flower 5 mm diameter, with four white petals. The fruit is a dry capsule 6–8 mm diameter, containing numerous 1–2.5 mm seeds.

1 Cultivation and uses
2 Black henna
3 See also
4 External references

[edit] Cultivation and uses

Henna is used as a temporary brown dye for hair colouring and temporary body art. Henna is also used to decorate lamps and bags. It is mainly known as Mehndi (or Mehendi/Mehandi) in India, Pakistan and Bangladesh. In North Africa and the Middle East it is typically called Henna. The dye is extracted from the dried leaf and petioles of the plant.

In Tamil (South India, Singapore, Malaysia, Srilanka) it is called as 'Marudhaani', and used as ground fresh leaves rather than as dried powder.

The application of henna has many uses. For instance, if you apply it to salt-cured goat skin bags, it is supposed to "insect-proof" or "moth-proof" the bags by making the skin inedible to pests. This has been observed with bagpipe bags from Tunisia such as the "Zukra" or "Mezoued" as well as Iran with the "Nay-anban" or "Habouneh".^{[citation needed]}

The United States Food and Drug Administration has not approved henna for direct application to the skin. It has been approved in order to add a deep red or brown tint and shine to hair. Most other cultures consider naturally-made henna to be harmless, though some products known as black henna with added paraphenylenediamine have been adulterated and can cause allergic reactions and permanent tissue damage. Black henna can be identified simply by its black color. However, all henna paste that is black is not necessarily "black henna".

[edit] Preparation and Application of Paste

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Image:Henna for hair.jpg

To prepare henna for skin or hair, the leaves are dried and ground into a powder. Strong tea or coffee, lemon juice (or other acidic liquid) and essential oils (such as tea tree, eucalyptus, clove and lavender) can be used to release the dye. It is then mixed in order to produce a mud-like consistency that will adhere well to the skin. The paste is then allowed to oxidize for an amount of time ranging from a few hours to two days before use. After the paste has been applied, it should stay on the skin as long as possible, up to 12 hours to achieve a stain of darkest coloration.

When the paste is dried and ready to be removed, it is often treated with a mixture of sugar, water, and lemon juice in order to allow the color to better penetrate the skin. Afterwards the paste can be picked or scratched off and dabbed with olive oil in order to further darken the stain. Stain colour and quality will improve in the 1-3 days after paste removal- the stain oxidizes and darkens substantially.

[edit] Chemistry and Allergic Reactions

Lawsone, the dye molecule in henna will bind with protein, such as the keratin in fingernails, hair, and skin. If you apply henna to skin, the lawsone molecules will migrate from the henna paste into the outermost layer of the skin [stratum corneum] and stain, just as the tannin molecules migrate from a wet teabag and stain a white tablecloth. Soles and palms have a very thick layer of skin, and take up the most lawsone, and to the greatest depth, so that hands and feet will have the darkest and most long-lasting stains. Though henna will stain skin within minutes, the longer the paste stays in contact with the skin, the greater the saturation, and darker the color. The stained skin will darken over a period of two or three days, then will appear to fade. The henna stain is not actually fading, the skin is exfoliating: the lower, less stained cells, rise to the surface, until all stained cells are shed.

Allergic reactions to natural henna are rare. The onset of a reaction to natural henna occurs within a few hours, symptoms being itching, shortness of breath, and/or tightness in the chest. Some people have an allergic reaction to an essential oil used to "terp" the mix, and some are allergic to lemon juice often used to mix henna.

Lawsone, the dye molecule in henna, can cause hemolytic oxidation in people who have G6PD deficiency, an inherited blood type. A large application of henna to a child with G6PD deficiency (such as scalp, palms and soles) may cause severe hemolytic crisis and may be fatal. Ingestion of a henna by a person with G6PD deficiency can be fatal.

Henna, indigo, and cassia are often sold as hair dyes under the names "red henna", "black henna" and "neutral henna", and they look nearly identical, all being powdered green leaves. Indigo (indigofera tinctoria) and cassia (cassia obovata or cassia alata) are NOT henna. There is no such plant as black henna, nor is there any such plant as neutral henna. Henna has a distinctive smell, like a hay bale. Indigo smells like frozen peas, and cassia smells like a mowed lawn.

[edit] Use of henna as body art

Image:Mehndi on hand with camel.jpg The application of henna is most popularly used on the body as a temporary tattoo. This usage is popular all over the world. It is usually drawn on the hands and feet, where the designs will last the longest.

Henna paste is usually applied to the skin using a plastic cone or a paint brush, but sometimes a small metal-tipped jacquard bottle used for silk painting (a jac bottle) is used. The affected area is then wrapped with tissue, thin cotton material, or plastic in order to lock in body heat, creating a more intense colour on the skin. The wrap is worn as long as possible and then removed. The final colour is reddish brown and can last anywhere from one week to four weeks depending on the quality of the paste.

The patterns of Mehndi are typically quite intricate, and predominantly applied to brides before wedding ceremonies in India. However, traditions in many parts of the world such as Bangladesh, India, and Sudan bridegrooms are to be painted as well. In Rajasthan (northwest India), where mehndi is a very ancient folk art, the grooms are given designs which are often as elaborate as those for brides. In Kerala (South India), Henna is known as Mylanchi and is commonly used by the Mappila (Muslim) community during weddings and festivals. In other countries, such as Morocco, it is done for any special occasion. It is done during the 7th month of pregnancy, after having the baby, weddings, engagements, family get-togethers, as well as many other reasons to simply celebrate an event.

Henna has lately become fashionable in the West as well, where they are sometimes called "henna tattoos". This colloquialism is misleading as tattoos are usually defined as the permanent surgical insertion of pigments underneath the skin.

[edit] Black henna

"Black henna" is the name given to an artificial product created by the addition of paraphenylenediamine (PPD) to natural henna to create a black stain. PPD is traditionally used in black hair dye but is a sensitizer, which means that it is something that the body is naturally allergic to or can become allergic to. Black henna can cause severe reactions that can take from 5–15 days to appear, which can cause permanent scarring and may even be life threatening. Reactions to black henna frequently necessitate immediate medical attention from a doctor or allergist.

However, other dyes exist which are sometimes called "black henna," which are usually composed of a mixture of henna and indigo. These generally do not contain PPD.