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Strychnos angolensis Gilg

Protologue
Bot. Jahrb. Syst. 17: 571 (1893).
Family
Loganiaceae
Chromosome number
2n = 88
Origin and geographic distribution
Strychnos angolensis occurs from Nigeria east to Tanzania, and south to Angola and Mozambique.
Uses
Strychnos angolensis was recorded as being used as ordeal poison in the Equateur province in DR Congo. In Cameroon the branches are used to make arrow shafts.
Properties
The root and stem bark of Strychnos angolensis contain at least 15 alkaloids: gentianine, aspidospermine, akuammicine, tubifoline, condylocarpine, akuammidine, 16(R)-epi-isositsirikine, 16(S)-epi-isositsirikine, tubifolidine, normavacurine, antirhine (anthirine), strychnofluorine (18-hydroxy-nor-C-fluorocurarine), flavopereirine, caracurine VII-N-oxide (WGA N-oxide) and tubotaiwine; the last two are the major components. The stem bark also contains the tertiary dimeric alkaloid caracurine V. In pharmacological screenings of bark extract, convulsive effects have been shown in the nonpolar part of the tertiary alkaloid fraction, while the polar fraction showed a strong muscle-relaxant activity. Strychnos angolensis has a considerable amount of mucilage in the leaves. The fruit pulp contains the polyphenol caffeic acid.
In-vitro tests of leaf and root extracts showed moderate antiplasmodial activity against Plasmodium falciparum.
Botany
Large liana up to 30 m long, climbing by solitary tendrils or shrub to small tree up to 12 m tall; stem up to 20 cm in diameter; bark pale brown; branches medium to dark brown, branchlets green, ochrous hairy. Leaves opposite, simple and entire; stipules absent; petiole 1–5 mm long, ochrous hairy; blade ovate to elliptical, 2–7(–10) cm × 1–4(–5) cm, base cuneate to rounded, apex obtuse to acute or acuminate, glabrous or hairy on the veins especially at the base, 3-veined from the base. Inflorescence an axillary or sometimes terminal lax thyrse 1–6 cm long, few-flowered; peduncle ochrous hairy. Flowers bisexual, regular, 4–5-merous; sepals broadly ovate, 0.5–1 mm long; corolla tube c. 0.5 mm long, lobes ovate to triangular, 1.5–2 mm long, acute, spreading, outside glabrous or minutely hairy, inside hairy at base, white or yellow; stamens inserted at the mouth of the corolla tube, just exserted; ovary superior, globose or broadly ovoid, c. 1 mm in diameter, 2-celled, gradually narrowing into the style c. 0.5 mm long, stigma head-shaped. Fruit an ellipsoid to globose, glaucous berry c. 12 mm × 12–22 mm × 18 mm, soft, orange or red, 1-seeded. Seed ellipsoid, 8.5–15 mm × 6–11 mm × 5–9 mm, smooth, glabrous, dark brown, shiny.
Strychnos comprises about 200 species: about 60 species in Asia, 65 in America and 75 in Africa. Strychnos angolensis belongs to the section Breviflorae. Also in this section is Strychnos malchairii De Wild., which occurs in DR Congo; the Mbuti and Efe people use the pounded bark to make an arrow poison. The ground roots are applied as a paste to treat large ulcers. The stems are used to make arrow shafts. The flexible stem is also used as rope.
Ecology
Strychnos angolensis occurs in forest near river banks and in gallery forest, from sea-level up to 1500 m altitude.
Genetic resources and breeding
Strychnos angolensis is widespread and is not threatened by genetic erosion.
Prospects
It is likely that Strychnos angolensis will remain of little importance, unless further research shows new pharmacological activities of the alkaloids.
Major references
• Bisset, N.G., 1970. The African species of Strychnos. Part I. The ethnobotany. Lloydia 33(2): 201–243.
• Bisset, N.G. & Leeuwenberg, A.J.M., 1968. The use of Strychnos species in Central African ordeal and arrow poisons. Lloydia 31: 208–222.
• Bohlin, L., Rolfsen, W., Ströbom, J. & Verpoorte, R., 1979. Alkaloids and biological activity of Strychnos angolensis Gilg. Planta Medica 35: 19–30.
• Leeuwenberg, A.J.M., 1969. The Loganiaceae of Africa 8. Strychnos 3. Revision of the African species with notes on the extra-African. Mededelingen Landbouwhogeschool Wageningen 69–1. Wageningen, Netherlands. 316 pp.
• Leeuwenberg, A.J.M. (Editor), 1980. Angiospermae: Ordnung Gentiales. Fam. Loganiaceae. Die natürlichen Pflanzenfamilien. Second Edition. Band 28 b-1. Duncker & Humblot, Berlin, Germany. 255 pp.
Other references
• Bouquet, A. & Fournet, A., 1975. Recherches récentes sur les plantes médicinales congolaises. Fitoterapia 46(6): 243–246.
• Delaude, C., Thepenier, P., Jacquier, M.J., Nuzillard, J.M., Massiot, G. & Le Men-Olivier, L., 1995. Alcaloďdes de Strychnos angolensis. Bulletin de la Société Royale des Sciences de Ličge 64(4–5): 243–246.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Ohiri, F.C., Verpoorte, R. & Baerheim Svendsen, A., 1983. The African Strychnos species and their alkaloids: a review. Journal of Ethnopharmacology 9(2–3): 167–223.
• Philippe, G., Angenot, L., De Mol, P., Goffin, E., Hayette, M.P., Tits, M. & Frédérich, M., 2005. In vitro screening of some Strychnos species for antiplasmodial activity. Journal of Ethnopharmacology 97(3): 535–539.
• Terashima, H. & Ichikawa, M., 2003. A comparative ethnobotany of the Mbuti and Efe hunter-gatherers in the Ituri forest, Democratic Republic of Congo. African Study Monographs 24(1–2): 1–168.
• Terashima, H., Kalala, S. & Malasi, N., 1992. Ethnobotany of the Lega in the tropical rain forest of Eastern Zaire: part two, zone de Walikale. African Study Monographs, Supplement 19: 1–60.
• Verpoorte, R., Bohlin, L., Dwuna-Badu, D., Rolfsen, W. & Ströbom, J., 1983. 11-methoxy-macusine A. A new quaternary alkaloid from Strychnos angolensis. Journal of Natural Products 46: 572– 575.
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., 2008. Strychnos angolensis Gilg. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.