Henna (Lawsonia alba., Lythraceae) is native to a number of tropical regions in Asia, northern Africa, and Australia. Henna is best known for the ground leaves (also called henna) traditionally used to develop a orange, red, brown or black coloring to hands, feet and hair. The leaves of henna have been used in Asia and the Middle East since ancient times as a hair, nail, and skin dye. The use of henna by the Egyptians to dye skin dates back to about 5000 years ago, who painted the nails of the dead with henna.

The term henna also refers to the ceremonial and cosmetic applications of this plant dye on the feet and hands for occasions such as weddings, and religious festivals. In India, Mehendi is a term that refers to the process as well as the henna plant dye and dates back to the 12th century.

Henna is cultivated in India, Middle East, and parts of tropical America. Henna is planted in home gardens as living hedges and as ornamental specimen plants. The henna leaves are used in Asia as a natural hair, nail, and skin dye. Different cultures across North Africa, the Middle East, and parts of Asia, including India, apply henna to the hands, feet, and hair.

Henna plant is a perennial shrub branching profusely and reaching a height of up to 20 ft (6 m). The plant grows rapidly and resembles a bush. It is often pruned to maintain a living hedge around homes and buildings, or grown as specimen trees in gardens. The leaves are rather small, about 2-3 cm (0.7 to 1.2 in) long and 1-2 cm (0.4 to 0.8 in) wide, lanceolate, dark-green, glabrous, opposite, with very short petioles. Flowers are numerous, small, white or pale pink colored and fragrant. The plant leaf contains a red orange color component, lawsone (2-hydroxy-1, 4-Napthoquinone). The fruits (capsules) are borne in clusters, green in color, turning red and then brown upon ripening.

Mehendi is the traditional Indian art of henna painting or henna tattooing of fine designs and patterns on women's hands and feet, especially before weddings and engagements. In India, where most marriages are by arrangement by parents of the bride and the groom, the henna ceremony provides an opportunity for the bride and groom to become acquainted. As bride and groom wait for the henna paste to dry, they are allowed to be in the presence of each other and talk about their future. Henna is also considered a sign of auspicious and good fortune, and a sign of joy. Henna is believed to have a cooling effect on the body and the paste is used to bring down fever and in several medicinal preparations of Ayurvedic, Siddha and Unani medical systems. Fresh leaves are ground and boiled in coconut oil and used as hair oil for stimulating the growth of lustrous hair.

Henna is also mixed with indigo and other plant materials or chemicals to obtain a greater color range from a light red to black. Sometimes lemon juice, tea leaves, tea bags, and natural oils such as eucalyptus oil and coconut oil are used to enhance the color of henna and to obtain a longer lasting pigmentation of the skin and hair. Henna paste applied to the skin is often left overnight and the color lasts up to three weeks. Henna is traditionally used in hair cleansing, conditioning, and occasionally as a temporary dye to color fabrics and textiles. Henna is also used as a medicinal plant, because of its attributed antibacterial, antifungal, astringent, antihemorrhagic, hypotensive, and sedative effects. It has also been used as a folk remedy against headache, jaundice, and leprosy in many world cultures (1).

Today, the use of henna has increased tremendously around the world for temporary coloring of the hands, feet and hair and gained commercial importance not only for hair coloring but also as a hair conditioner, hair growth promoter, and for hair brightening. The oil extracted from henna flowers is used in the perfume industry.

Domestic use of henna in Asia, Africa and the Middle East consists of picking fresh henna leaves and grinding to a paste and use to color hand, feet, and in the preparation of hair oils. Henna leaves are dried and processed commercially to a powder or paste form and available for use where fresh henna leaves are not obtainable. Henna is known for its hair conditioning effects and favorably used over commercial hair dyes in the place of synthetic chemicals.

Scientific studies prove that henna is a better hair conditioner than other commercial conditioners (2). Henna is being investigated for its antimicrobial, antibacterial and anti-fungal properties (3-4). Crude alcoholic extracts of henna produced significant anti-inflammatory, analgesic, sedative, and antipyretic effects in rats (5). The henna fruits are antiviral (6), and the bark extracts are protective of the liver preventing oxidative stress (7-8).

REFERENCES

1. Hanke M, Talaat SM. 1961. The biochemistry and physiology of henna (Lawsonia alba): its use as a remedy for intestinal amoebiasis. Trans Roy Soc Trop Med Hyg 55:56-62.
2. Cajkovac M, Oremovic L, Cajkovac V. 1996. The effect of hair colors and perm products on the state of hair. Acta Pharm 46(1):39-49.
3. Malekzadeh F, Shabestari PP. 1989. Therapeutic effects and in vitro activity of an extract from Lawsonia inermis. J Sci Islamic Repub 1(1):7-12.
4. Rosenberg NM. 1999. Antibacterial deodorizing compositions containing extracts of Lawsonia inermis. PCT Int Appl 37 pp.
5. Ali BH, Bashir AK, Tanira MOM. 1995. Anti-inflammatory, antipyretic, and analgesic effects of Lawsonia inermis L. (henna) in rats. Pharmacology 51(6):356-363.
6. Khan MM, Ali A, Jain DC, Bhakuni RS, Zaim M, Thakur RS 1991. Occurrence of some antiviral sterols in Artemisia annua. Plant Sci 75(2):161-165.
7. Ahmed S, Rahman A, Alam A, Saleem M, Athar M, Sultana S. 2000. Evaluation of the efficacy of Lawsonia alba in the alleviation of carbon tetrachloride-induced oxidative stress. J Ethnopharm 69(2):157-164.
8. Anand KK, Singh B, Chand D, Chandan BK 1992. An evaluation of Lawsonia alba extract as hepatoprotective agent. Planta Medica 58(1):22-25.

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