Prota 3: Dyes and tannins/Colorants et tanins
Bull. Inst. Franç. Afrique Noire, ser. A , 16: 62 (1954).
Grumilea psychotrioides DC. (1830).
Azier, café marron (Fr).
Origin and geographic distribution
Psychotria psychotrioides is distributed from Senegal east to Sudan, and south to Gabon and DR Congo.
The bark of Psychotria psychotrioides yields a red dye which is used to dye textiles, e.g. in Sierra Leone. In Senegal early symptoms of eye troubles are treated with a decoction of the bark in a steam bath, whereby a sheet covers the head of the patient and the container with the steaming liquid. To combat headache and depressions a leaf maceration is rubbed on the forehead or the sap is drunk. The root or whole plant yields a widely used expectorant medicine for asthma and bronchitis.
The chemical nature of the red dye has not been studied. Whatever the chemical composition of the red dye is, the dye potential of Psychotria psychotrioides is optimized by the mordanting effect of the high concentration aluminium present in the leaves. Aluminium accumulation in leaves seems to be a chemotaxonomic characteristic of Psychotria. Aluminium salts are the main mordants used to strengthen and multiply the chemical bonds between textile fibres and most natural dyes.
Shrub up to 6 m tall, with rounded, glabrous branches; bark pale brown, c. 3 mm thick. Leaves opposite, simple and entire, glabrous; stipules oblong-ovate, 7–15 mm long, not persistent; petiole 1–6 cm long; blade elliptical, ovate, obovate or linear, 5–30 cm × 1–15 cm, base rounded to cuneate, apex acute to rounded, lateral veins in 5–12 pairs. Inflorescence a sessile head 1–1.5 cm in diameter, densely clustered, subtended by 2 circular, deciduous bracts c. 1 cm in diameter. Flowers bisexual, regular, 5–6-merous, heterostylous, sweet smelling, sessile; calyx campanulate, 3–5 mm long, irregularly incised; corolla tubular, tube 6–10 mm long, lobes up to 3 mm long, white; stamens in long-styled flowers up to 1 mm long, in short-styled ones up to 3 mm; disk rounded; ovary inferior, 2-celled, glabrous, style up to 5 mm long in short-styled flowers, up to 8 mm in long-styled ones, stigmas 2, up to 1.5 mm long. Fruit a globose to ellipsoid drupe, 8–13 mm × 6–9 mm, red, strongly ribbed, with persistent calyx at apex, containing 2 pyrenes.
Psychotria is a very large and insufficiently known genus comprising about 500 species distributed pantropically. About 200 species are present in tropical Africa. The genus is classified in subfamily Rubioideae, tribe Psychotrieae and it is subdivided in various subgenera and sections, but this classification has not yet stabilized. Psychotria psychotrioides is easily recognized by its sessile head-like inflorescences subtended by large bracts when young; the leaves are very variable.
In the literature the following African Psychotria species have also been reported as yielding a red dye in the bark and sometimes also leaves, which is used to dye textiles:
– Psychotria bidentata (Thunb. ex Roem. & Schult.) Hiern: shrub up to 6 m tall; leaves elliptical, 7–19 cm × 2–8 cm; inflorescence head-like, peduncle up to 11 cm long; flowers white, 5-merous, heterostylous; calyx tube less than 1.5 mm long, lobes less than 1 mm long. It occurs in forests from Senegal to Benin. In Sierra Leone a root decoction is given to babies with stomach-ache.
– Psychotria reptans Benth. (synonym: Psychotria strictistipula Schnell): small shrub up to 60 cm tall; leaves elliptical, 5–16 cm × 1.5–6 cm; inflorescence paniculate, peduncle up to 6 cm long; flowers white, 5-merous; calyx tube 1–1.5 mm long, lobes shorter; fruits white. It occurs in forests from Guinea to Ghana.
– Psychotria rufipilis De Wild.: shrub up to 1.5 m tall; leaves obovate to elliptical, 4–20 cm × 1.5–8 cm, veins hairy; inflorescence paniculate or head-like, peduncle up to 5 cm long; flowers white, sessile or pedicellate, 5-merous, heterostylous; calyx tube 1.5–2 mm long, lobes 1–2 mm long. It occurs in savanna and gallery forest from Guinea to Côte d’Ivoire. In Liberia an astringent drink or liquor is made from the bark (sometimes leaves added) and given to children with peeling skin and diarrhoea.
Psychotria psychotrioides is found in closed and fringing forest and in savanna woodland, from sea-level up to 1200 m altitude.
Genetic resources and breeding
Psychotria psychotrioides is very widespread and common in Africa and is not in danger of genetic erosion.
As sources of a red dye, the bark and leaves of Psychotria psychotrioides and several other Psychotria species may remain of minor importance locally but with the present emergence of worldwide interest in natural dyes as renewable sources of non-polluting colorants, the combination in the same plant of a red dye and a mordant makes Psychotria psychotrioides a potentially interesting source of red colorants. Its chemical composition and medicinal properties need further research.
• Burkill, H.M., 1997. The useful plants of West Tropical Africa. 2nd Edition. Volume 4, Families M–R. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 969 pp.
• Petit, E., 1964. Les espèces africaines du genre Psychotria L. (Rubiaceae). 1. Bulletin du Jardin Botanique de l'Etat (Bruxelles) 34: 1–229.
• Hepper, F.N. & Keay, R.W.J., 1963. Rubiaceae. In: Hepper, F.N. (Editor). Flora of West Tropical Africa. Volume 2. 2nd Edition. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. pp. 104–223.
• Hiern, W.P., 1877. Rubiaceae. In: Oliver, D. (Editor). Flora of tropical Africa. Volume 3. L. Reeve & Co, Ashford, United Kingdom. pp. 33–247.
• Irvine, F.R., 1961. Woody plants of Ghana, with special reference to their uses. Oxford University Press, London, United Kingdom. 868 pp.
• Jansen, S., Dessein, S., Piesschaert, F., Robbrecht, E. & Smets, E., 2000. Aluminium accumulation in leaves of Rubiaceae: systematic and phylogenetic implications. Annals of Botany 85: 91–101.
• Kerharo, J. & Adam, J.G., 1974. La pharmacopée sénégalaise traditionnelle. Plantes médicinales et toxiques. Vigot & Frères, Paris, France. 1011 pp.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• PharmaPro, 1997–2002. Azier. [Internet] http://www.pharnet.com/public/phytotherapie/plantes/phyto_azier.htm. Accessed May 2005.
Correct citation of this article:
Jansen, P.C.M., 2005. Psychotria psychotrioides (DC.) Roberty In: Jansen, P.C.M. & Cardon, D. (Editors). PROTA 3: Dyes and tannins/Colorants et tanins. [CD-Rom]. PROTA, Wageningen, Netherlands.