Henna is perhaps the most commonly used cosmetic of all time. It was used to decorate the skin as long as five thousand years ago. Archeologists have even discovered henna on the hair and nails of Egyptian mummies!
Henna remains popular today, especially in India, North Africa, Southeast Asia and the Middle East. It has also caught on in Canada, especially during the summer months when henna art stands seem to pop up at almost any outdoor concert or festival.
In India, henna is referred to as mehndi which is also used to describe the art of applying henna to the body in a variety of intricate patterns. In general, Indian designs consist of delicate floral and paisley patterns. The designs though differ depending on which part of the world you are in. For example, in Arabia, the designs have larger floral motifs on the hands and feet whereas African designs are made up of bold geometric shapes.
Did You Know?
The art of mehndi is considered as mainly a feminine art in parts of the world such as Asia, Africa and the Middle East. Most mehndi designs are associated with religious beliefs and values. One of the most important occasions for which mehndi is used is the wedding ceremony.
In India, the hands and feet of brides are decorated with henna and it is believed to bring good luck to the couple. A popular Indian legend about mehndi tradition states that the darker the henna stains the skin, the more the groom's mother will love her new daughter-in-law.
Henna: The Plant
Henna (Lawsonia inermis) is a flowering plant, a bright-green tall shrub. It is the only species in the genus Lawsonia, in the family Lythraceae. It originates from Egypt where it thrives in that country's hot and dry weather. However, it is also an indigenous plant in the tropical and subtropical regions of Africa, southern Asia, and northern Australasia in semi-arid zones.
Henna has the potential to grow to 4.6 meters, but it is often harvested when it is 2.4 - 3 meters tall, about three times a year. Henna is the Persian name for this plant with small leaves and thick bark. Henna's flower has four petals and elongated stamen protruding from the center. The red, rose pink and white blossoms have a sweet honey-like scent, like jasmine and rose, and the flower's oil can be used to make perfumes.
Lawsone: The Dye
Henna produces lawsone, a red-orange dye molecule that is mainly concentrated in the leaves of henna, especially in the petioles. This molecule has an affinity or attraction for bonding with protein, and thus has been used for many purposes such as dyeing protein-rich substances such as skin, hair, fingernails, leather, silk and wool.
Henna paste, made from the crushed leaves of the henna plant, is used for making temporary tattoos. Uncrushed henna leaves do not stain the skin since lawsone molecules have not been released from the henna leaf. Smashed henna leaves are typically mixed with a mildly acidic liquid which helps to release the lawsone from the leaves during the crushing process.
Did You Know?
Mildly acidic solutions include lemon juice or strong tea and are typically used for preparing henna paste from commercially available henna powder (made by drying the henna leaves and grinding them to powder). When the paste is applied to the skin, the lawsone stains the outermost layer of the skin (the epidermis) with a red-brown color that gradually fades over a three-week period. Skin usually gets stained within minutes, but the longer the paste is left on the skin, the more lawsone will migrate and the darker the pattern will become.
So if you've been dying (pardon the pun) to get a tattoo and are wondering if you're going to like having permanent body art, or just want to decorate that bare skin you're showing off this summer, its henna to the rescue! It can even be good for you; it acts as a sun block and is thought to strengthen your skin
Batra, sumita. The art of Mehndi. Carlton books limited. London. 1999.
Wikipedia on Henna
For more information on permanent tattoos, see the CRAM Science article series on tattoos:
Part One: The Tools
Part Two: The Skin
Photo credit: The Herb Specialist
Aida is a graduate student at the University of Toronto where she studies cell biology. She also tutors students in her free time, helping to spread her love for biology.