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Rauvolfia media Pichon

Protologue
Bull. Soc. Bot. France 94: 36 (1947).
Family
Apocynaceae
Synonyms
Rauvolfia confertiflora Pichon (1947).
Origin and geographic distribution
Rauvolfia media is endemic to Madagascar and Comoros.
Uses
The bark of young twigs and the leaves are crushed and applied to the eyes to cure viral conjunctivitis. The crushed roots or a decoction of the roots and bark, mixed with food, are used to poison dogs with rabies and also pest animals. The latex can be used as glue for small utensils.
Production and international trade
The bark and roots are exported to Europe for the pharmaceutical industry. Between 1986 and 1995, about 16.5 t/year were exported.
Properties
All parts are very bitter and are considered very toxic. The bark and roots contain several monomeric indole alkaloids, of which reserpiline is pharmacologically active. It has sympatholytic and hypotensive properties, with no noticeable depressant effects on the central nervous system. In comparison with reserpine, which is present in other Rauvolfia spp., reserpiline does not induce the formation of gastric ulcers, has no laxative effects and lacks other side effects.
Botany
Shrub or small tree up to 10(–15) m tall; bark grey or pale brownish-grey, smooth. Leaves in whorls of 4–7, crowded at the top of branches, simple and entire; stipules absent; petiole 0.5–1.5 cm long; blade ovate or elliptical to narrowly oblong, 1–18 cm × 0.5–8.5 cm, base cuneate, apex obtuse. Inflorescence a terminal, lax to congested cyme; peduncle 1.5–5.5 cm long, hairy to glabrous. Flowers bisexual, regular, 5-merous, fragrant; pedicel 1–4 mm long; sepals fused at base, unequal, ovate to narrowly oblong, c. 2 mm long; corolla tube cylindrical, 3–6 mm long, widening at the insertion of the stamens, slightly narrowed at the mouth, lobes axe-shaped, 1.5–2.5 mm long, shortly hairy or glabrous on both sides, white to dull yellow; stamens inserted at 2.5–4.5 mm above the corolla base, barely included or exserted; ovary superior, globose, oblong to ovoid, composed of 2 partly fused carpels, style 1–4 mm long, pistil head cylindrical with a basal collar and a stigmoid apex. Fruit an obcordate to ovoid or subglobose drupe 6–10 mm long, laterally compressed, 1–2-seeded. Seeds ellipsoid, 4–10 mm long, laterally compressed.
Rauvolfia is a pantropical genus of about 60 species, of which 7 occur in continental Africa, 2 in Madagascar, and 1 in Madagascar and the Comoros. The 2 other Rauvolfia species present in Madagascar are confined to the northern region. The roots of Rauvolfia obtusiflora A.DC. are used as a fish poison, whereas the aerial parts in decoction were formerly used as an ordeal poison. The roots are rich in indole alkaloids, but do not contain reserpine. A decoction of the aerial parts of Rauvolfia capuronii Markgr. was formerly taken as ordeal poison. Rauvolfia media flowers from September to December and fruits from November to February. Young leaves appear just before or with the flowers.
Ecology
Rauvolfia media occurs in dry forest and savanna, from sea-level up to 800 m altitude.
Genetic resources and breeding
Because of the rapid destruction of the forests in which it occurs and harvesting for local use and export, Rauvolfia media may become rare and locally threatened.
Prospects
More research is needed to identify the pharmacologically active alkaloids in the different plant parts. The exploitation of Rauvolfia media as well as the decline of its natural habitat have caused the species to become rare, and unless it is domesticated and planted, the exploitation will come to a halt.
Major references
• Boiteau, P., Boiteau, M. & Allorge-Boiteau, L., 1999. Dictionnaire des noms malgaches de végétaux. 4 Volumes + Index des noms scientifiques avec leurs équivalents malgaches. Editions Alzieu, Grenoble, France.
• Markgraf, F., 1976. Apocynaceae. Flore de Madagascar et des Comores, famille 169. Muséum National d’Histoire Naturelle, Paris, France. 318 pp.
• van Dilst, F.J.H. & Leeuwenberg, A.J.M., 1991. Rauvolfia L. in Africa and Madagascar. Series of revisions of Apocynaceae 33. Bulletin du Jardin Botanique Nationale de Belgique 61(1–2): 21–69.
Other references
• Andriatsiferana, R., 1997. Valorisation des activités biologiques de la biodiversité végétale: plantes médicinales. In: Ministère de l’environnement, Ministère des eaux et forêts, Office National de l’Environnement (Editors). Monographie nationale sur la biodiversité. Antananarivo, Madagascar. pp. 243–248.
• Kan, C., Potier, P., Kan, S.-K., Jokela, R. & Lounasmaa, M., 1986. Indole alkaloids from Rauvolfia media. Phytochemistry 25(7): 1783–1784.
• Neuwinger, H.D., 1996. African ethnobotany: poisons and drugs. Chapman & Hall, London, United Kingdom. 941 pp.
• Rasoanaivo, P., Petitjean, A. & Conan, J.Y., 1993. Toxic and poisonous plants of Madagascar: an ethnopharmacological survey. Fitoterapia 64: 117–129.
Author(s)
G.H. Schmelzer
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:
Schmelzer, G.H., 2007. Rauvolfia media Pichon. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.