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Pleioceras barteri Baill.

Protologue
Bull. Mens. Soc. Linn. Paris 1: 759 (1888).
Family
Apocynaceae
Chromosome number
2n = 22
Origin and geographic distribution
Pleioceras barteri occurs from Sierra Leone to Cameroon and the Central African Republic.
Uses
The bark and, more frequently, the seeds are used in Côte d’Ivoire as an emmenagogue. In Nigeria, the fruits are used similarly. A strong dose is abortifacient and careless usage may cause death. Nevertheless it is taken by women once or twice a month during late pregnancy to induce the turning down of the head of the baby. The bark crushed together with the fruit of Ricinodendron heudelotii (Baill.) Pierre ex Heckel is applied to boils in the groin to hasten maturation. A plaster of leaves is applied against rheumatism and the fruit pericarp, prepared as an ointment, is used to treat nosebleed. In Nigeria, Pleioceras barteri is also used in traditional medicine to treat malaria. The ash of dried and burnt whole plants is applied against burns.
Production and international trade
Pleioceras barteri is collected from the wild and traded locally.
Properties
Pleioceras barteri contains alkaloids, saponins, tannins and flavonoids. The seeds are the most toxic part of the plant with total alkaloids amounting to 0.3%. The fruit wall contains 0.1% and the root bark 0.01% alkaloids. From the leaves, 0.6% ursolic acid has been isolated; this compound has anti-infective properties.
Pleioceras barteri shows antibacterial activity against gram-positive bacteria. The methanol extract is active against several pathogenic bacteria, with Bacillus subtilis being most susceptible. The extracts showed limited activity against fungi. The stem, stem bark, root bark, seed and fruit extracts showed abortifacient properties and depressant or stimulant effects on the central nervous system in rats.
Secondary amines (including alkylamine, dimethylamine, diethylamine and ethylaniline) have been isolated from the roots of Pleioceras barteri. The use of this plant could thus result in the accumulation of amines in the body, which could lead to the formation of carcinogenic nitrosamines.
Botany
Shrub, small liana or small tree up to 4 m tall, with white latex in bark and leaves; bark dark brown; branchlets terete, hairy. Leaves opposite, simple and entire; stipules absent; petiole 2–5 mm long, hairy; blade narrowly ovate or obovate, 5–9 cm × 2–7 cm, base rounded or cuneate, apex acuminate, sparsely hairy to glabrous above, hairy on the main veins beneath. Inflorescence a lax terminal panicle, 5–14 cm long, many-flowered; bracts small; peduncle 1–4 cm long, sparsely hairy. Flowers bisexual, regular, 5-merous; pedicel 5–10 mm long, hairy; sepals 1–2 mm long, connate at base, calyx persistent in fruit; corolla tube 2–3 mm × 2–3 mm, lobes elliptical, 3–5 mm long, apex rounded, ciliate, dark red or violet, apex of lobes yellow, inside with up to 7 bright yellow appendages, 4 appendages broom-like, 2–5 mm long with 3–4 branches, central appendage oblong, 2–3 mm long, with 2 narrowly oblong lobes, 2 appendages filiform to oblong, 0.5–1.5 mm long, or absent or fused with appendages of neighbouring lobe; stamens inserted just below the corolla mouth, exserted, covered by the corolla appendages, base of anthers sagittate, apex acuminate; ovary superior, almost globose, consisting of 2 free carpels, styles fused except at the base, slender, 2–5 mm long, pistil-head small, almost cylindrical, covered by the anthers and inside with triangular swellings of the connectives adnate to the clavuncula. Fruit consisting of 2 linear almost free follicles, 25–65 cm long, spreading, pendulous, dark green, glabrous, dehiscent with a longitudinal slit, many-seeded. Seeds linear to very narrowly oblong, 13–27 mm long, finely grooved, pale yellow, with a dense 3–7 cm long tuft of hairs at apex.
Pleioceras comprises 5 species, all occurring in tropical continental Africa. It is closely related to Wrightia. Pleioceras barteri flowers throughout the year.
Ecology
Pleioceras barteri occurs in forest, bush or open localities, mostly near the coast, up to 500 m altitude.
Genetic resources and breeding
Pleioceras barteri is widespread mainly in the western Africa coastal regions and does not seem to be in danger of genetic erosion.
Prospects
Not much is known of the pharmacological properties of Pleioceras barteri, although it has some interesting uses in traditional medecine. The strong abortifacient effect of the seeds warrants further investigation, as do the antibacterial activities.
Major references
• Adjanohoun, E.J., Adjakidjè, V., Ahyi, M.R.A., Aké Assi, L., Akoègninou, A., d’Almeida, J., Apovo, F., Boukef, K., Chadare, M., Cusset, G., Dramane, K., Eyme, J., Gassita, J.N., Gbaguidi, N., Goudote, E., Guinko, S., Houngnon, P., Lo, I., Keita, A., Kiniffo, H.V., Kone-Bamba, D., Musampa Nseyya, A., Saadou, M., Sodogandji, T., De Souza, S., Tchabi, A., Zinsou Dossa, C. & Zohoun, T., 1989. Contribution aux études ethnobotaniques et floristiques en République Populaire du Bénin. Agence de Coopération Culturelle et Technique, Paris, France. 895 pp.
• Agbedahunsi, J.M., Oloke, J.K. & Aladesanmi, A.J., 1993. Antimicrobial activity of Pleioceras barteri root extract. Fitoterapia 64(1): 81–82.
• Aladesanmi, A.J., Sofowora, A. & Leary, J.D., 1986. Preliminary biological and phytochemical investigation of two Nigerian medicinal plants. International Journal of Crude Drug Research 24(3): 147–153.
• Barink, M.M., 1983. A revision of Pleioceras Baill., Stephanostema K. Schum. and Schizozygia Baill. (Apocynaceae). In: Leeuwenberg, A.J.M. (Editor). Series of revisions of Apocynaceae 11–13. Mededelingen Landbouwhogeschool Wageningen 83–7. Wageningen, Netherlands. pp. 21–55.
• Uhegbu, F.O. & Maduagwu, E.N., 1995. Occurrence of nitrosatable amines in some Nigerian medicinal plants. Bulletin of Environmental Contamination and Toxicology 55(5): 643–649.
Other references
• Bisset, N.G., 1983. Phytochemistry of Pleioceras and Stephanostema. In: Leeuwenberg, A.J.M. (Editor). Series of revisions of Apocynaceae 11–13. Mededelingen Landbouwhogeschool Wageningen 83–7. Wageningen, Netherlands. p. 52.
• Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families A–D. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 960 pp.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
Sources of illustration
• Akoègninou, A., van der Burg, W.J. & van der Maesen, L.J.G. (Editors), 2006. Flore analytique du Bénin. Backhuys Publishers, Leiden, Netherlands. 1034 pp.
Author(s)
A. de Ruijter
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands


Editors
G.H. Schmelzer
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
A. Gurib-Fakim
Faculty of Science, University of Mauritius, Réduit, Mauritius
Associate editors
C.H. Bosch
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
M.S.J. Simmonds
Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, United Kingdom
R. Arroo
Leicester School of Pharmacy, Natural Products Research, De Montfort University, The Gateway, Leicester LE1 9BH, United Kingdom
A. de Ruijter
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
General editors
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
L.P.A. Oyen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article:
de Ruijter, A., 2006. Pleioceras barteri Baill. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
1, flowering twig; 2, flower; 3, fruit.
Source: Flore analytique du Bénin