Baptisia tinctoria (L.) R. Brown

Botany, Distribution, and Importance

Baptisia tinctoria (L.) R. Brown (synonyms: Sophora tinctoria L., Polydaria tinctoria Michaux Willd., commonly known as rattle bush, horsefly weed, indigo weed, yellow indigo, or yellow clover broom) and other members of the genus Baptisia were traditional medicinal plants for the American natives (Millspaugh 1887). Leaves of B. tinctoria were also used as a plant-derived dye (Gr. bapto, Lat. tingere: dye). It is a member of the family of Fabaceae (Leguminosae) and forms bushy shrubs up to 1 m high with woody perennial rhizomes and roots and annual aboveground parts. The round stems are usually erect, often widely branched, glabrous, occasionally slightly pubescent and yellowish green. The subsessile leaves are terminately compound, with subsessile cuneate, obovate leaflets of 1 to 1.5 cm length, and are bluish green in color.

The yellow flowers form loose terminal axillary racemes. The floral bracts are lanceolate-setaceous to ovate acuminate, the pedicels are 4 to 5 mm long, the calyx tube length is 3 to 4 mm. The corolla is papilionaceous, the upper part (standard) is about 1 cm long, the wings and the keel about 1.2 to 1.3 cm. The keel is curving upwards. The ten equally formed stamens are not united into a tube at the base.

The fruit is unilocular, unicarpellary, containing up to five seeds. Mature pods are up to 1 cm long, and 0.8 cm broad, subglobose to ovoid, strongly rounded at the base and the summit. The kidney-shaped yellow to dark brown seeds are 1 to 3 mm long, and 1 to 1.5 mm broad.

The genus Baptisia comprises more than 20 species. Interspecies hybridization is often seen, and has been proven by morphological analysis as well as by identification and comparison of alkaloid and flavonoid patterns.

Baptisia tinctoria is native to the eastern parts of North America and Southern Canada (Ontario). It is a general part of the natural flora and was described by European botanists as early as 1762 (Claytonus), and later in monographs (Meehan 1885; Larisey 1940).

The habitats of the wild, slow-growing plant are sandy grounds and natural openings with poor, well-drained slightly acidic soils. These areas were formerly kept open by animals or natural fires, but in the meantime, most of these habitats have been turned into agricultural and cultivated sites. In this way, the land suitable for B. tinctoria has diminished continuously. B. tinctoria as a slow-growing plant does not spread very fast and, due to the low germinability of its seeds, reproduction is low. It is probably not regenerated naturally as rapidly as it is being eliminated by sample collection. Thus, nowadays B. tinctoria occurs in a few scattered locations and its populations are becoming smaller. In order to ensure a continuing ample supply of rhizomes and roots for medicinal use, it will have to be taken into culture.

The crude drug, Radix Baptisiae tinctoriae, was utilized in the traditional medicine of the American Indians for preparing liquid aqueous extracts. The extracts were applied to wounds, bruises, and as laxans, especially in septic, inflammatory processes, ulcers and abscesses, etc.. The European settlers took over the use of this plant as an antiseptic against typhus and scarlet fever. In Europe, it was introduced into therapy as a homeopathic compound in the mid 19th century; later it was applied allopathically in septic processes (Madaus 1938).

Today, it is a well-known and accepted herb in phytotherapy. The aqueous-ethanolic extracts of B. tinctoria roots form an essential part of immune-modulating herbal products like “Esberitox”. These products are used in the treatment of acute and chronic viral or bacterial infections like common wed, bronchitis, angina laryngitis, otitis, and bacterial infections of the skin.

Demand on the World Market and Conventional Methods for Propagation

The demand for the drug, Radix Baptisiae tinctoriae, is increasing. In 1980 the demand for the crude drug in Germany was 2000 kg/year; 10 years later this had risen to 5000 kg.

Since the rootstocks are provided by collecting wild-grown material, their diversity has to be tested. Rootstocks of B. australis or B. alba occur as falsification. Both species are used as substitute for B. tinctoria ().

Conventional methods for propogation have never been described. There are historical references to the plant’s being cultivated in South Carolina in the 18th and 19th centuries (1744 until 1890) as a dye producer; but no reports on the manner of cultivation or the agricultural techniques used in the past are available. Recently, studies were carried out to cultivate B. tinctoria starting by seedling culture and by rhizome cuttings. Both methods are slow and time-consuming, and cannot be applied for mass production. Rhizomes used for vegetative propagation can be taken only from plants older than 3 years, because those of younger plants are too small and die after cutting. Furthermore, rhizomes are often attacked by soil borne fungi and bacteria, causing rhizome soft rot.

Propagation by seeds is possible, but germination in the field under natural conditions is poor, due to dormancy. Less than 3% of seeds germinated under natural conditions or in laboratory experiments. The best method for breaking dormancy is scarification by mechanical or chemical means, especially soaking the seeds in sulfuric acid. Detailed studies on seed dormancy and seedling variability have been carried out.


Mass propagation and maintenance of genetic stability of B. tinctoria by means of in vitro culture is possible. The cultivars (clones) in in vitro propagation differ considerably in vigor of growth and multiplication potential. Within more than 12 passages of in vitro cultivation no visible changes in plant behavior have been seen. Most clones of B. tinctoria can be easily transferred into nonsterile conditions.

Root formation of in vitro segments varies strongly with the clones used. The rooting procedure is under study to establish suitable modifications.

The medicinal quality is not correlated to alkaloid content but is due to glycoproteins in the roots, and must be tested for various genotypes in culture. The variability of glycoproteins in quality as well as in quantity in roots of different developmental stages and clones of B. tinctoria is under study.

Selections from the book: Medicinal and Aromatic Plants VII (1994).