Indigo

Scientific Name(S): Indigofera species including I. tinctoria (French indigo) and I. suffruticosa Mill. (Guatemalan indigo) formerly known as I. ani! L. Family: Fabaceae (Leguminosae).

Common Name(S): Common or Indian Indigo; not to be confused with false, wild or bastard indigo (Baptisia tinctoria L), a native North American plant from which a blue dye is obtained from the leaves.

Botany: These plants are perennial shrubs that reach a height of 1 m to 2 m. The French and Guatemalan varieties differ in the shape and size of the leaflets and pods.

History: Indigo refers to several species of Indigofera that are known for the natural blue colors obtained from the leaflets and branches of this herb. Before the development of synthetic aniline and indigo dyes, indigo plants were grown commercially in the East Indies and South and Central America. Indigo was a popular dye during the middle ages. It has been used medicinally as an emetic; the Chinese used the plant to purify the liver, reduce inflammation and fever and to alleviate pain. Extracts of I. tinctoria have been reported to have nematicide activity and the leaf and plant juice have been used to treat cancers, particularly of the ovaries and stomach. In addition, the plant has been used for the treatment of numerous ailments ranging from hemorrhoids to scorpion bites.

Uses of Indigo

Chiefly a source of dye, indigo has also been used as a nematicide and treatment for a range of ills including scorpion bites and ovarian and stomach cancer.

Side Effects of Indigo

Some species are toxic and cause birth defects.

Toxicology: Indigo appears to be a mild ocular irritant. Dermatitis is common among indigo dyers but there is no direct evidence that this is linked to exposure to the plant or dye. I. spicata is recognized as a teratogen due to the presence of indospicine. Indospicine also is hepatotoxic. In animals, it causes cleft palate and embryo lethality. I. endacaphylla (creeping indigo) has been responsible for livestock poisonings and deaths.

Summary: The Indigofera species have been used fer centuries as a natural source of an exquisite blue dye While the medicinal uses and claims for the plants are numerous, there is little evidence to verify these effeds. Several species of Indigofera are toxic.