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Strychnos afzelii Gilg

Protologue
Bot. Jahrb. Syst. 17: 572 (1893).
Family
Loganiaceae
Chromosome number
2n = 44
Origin and geographic distribution
Strychnos afzelii occurs from Senegal east to Nigeria.
Uses
In Senegal the crushed leaves and root of Strychnos afzelii together with the crushed leaves of Hugonia planchonii Hook.f. are applied to treat abscesses and swellings. In Sierra Leone a decoction of the seeds together with leaves of Ocimum sp. or other aromatic herbs is taken to promote sweating in case of fever attacks. Ground seeds are taken in soup to treat stomach-ache.
All parts of the plant smell like cloves, especially the twig bark. In Sierra Leone women of the Mende people rub the sap from crushed leaves, pure or mixed with white clay, on their bodies for the fragrance and as an aphrodisiac. In Sierra Leone and Côte d’Ivoire the twigs are used as chew-sticks. The Temne people of Sierra Leone chew the leaves to treat bad breath. Chewing makes the lips red, and in Ghana the leaves are chewed for this purpose.
Properties
The main indole alkaloids of Strychnos afzelii are the dimeric tertiary indole alkaloid bisnordihydrotoxiferine and its derivatives bisnordihydrotoxiferine N-oxide and bisnordihydrotoxiferine di-N-oxide, the monomeric caracurine VII (Wieland-Gumlich aldehyde), its acetyl derivative diaboline, the dimeric bisquaternary caracurine V and its derivative caracurine V N-oxide, the dimeric tertiary longicaudatine and its isomer bisnor-C-alkaloid H.
Stem bark extracts showed activity against several micro-organisms, including some species associated with caries. Bisnordihydrotoxiferine, bisnor-C-alkaloid H and caracurine VII showed antimicrobial effects. Bisnordihydrotoxiferine, isolated from the root bark of Strychnos trinervis (Vell.) Mart., showed a wide antimicrobial spectrum against gram-positive and gram-negative bacteria, and against filamentous and yeast-like fungi. Preliminary studies of this compound also revealed some cytotoxic activity in vitro against sarcoma 180 tumours. Bisnordihydrotoxiferine also showed a weak activity in vitro against Plasmodium falciparum.
Botany
Large liana up to 50 m long, climbing with solitary tendrils; branchlets medium green, yellowish hairy; lateral branches transformed into blunt spines 7–25(–35) mm long. Leaves opposite, simple and entire; stipules absent; petiole 1–5 mm long, almost glabrous; blade ovate, orbicular, elliptical, obovate or oblong, 1–11(–14.5) cm × 1–5.5(–6.5) cm, base cordate, rounded or cuneate, apex notched or rounded to acuminate, sparsely appressed hairy when young, later almost glabrous, 3-veined from the base. Inflorescence an axillary congested or lax thyrse 2–5 cm long, few- to many-flowered. Flowers bisexual, regular, 5-merous; sepals fused at base, broadly triangular to almost orbicular, up to 0.5 mm long; corolla tube up to 1 mm long, lobes narrowly triangular, 1–1.5 mm long, acute, erect, sparsely hairy outside, inside with a flat brush of white hairs on the lobes, white, creamy or pale yellowish green with slightly darker lobes; stamens inserted at the mouth of the corolla tube, included; ovary superior, broadly ovoid, 0.5 mm in diameter, glabrous, 2-celled, style very short, stigma white, globose. Fruit an obliquely ellipsoid, laterally compressed berry 11–16 mm × 9–13 mm × 9–11 mm, rather hard, orange, 1(–2)-seeded. Seed ellipsoid, 10–14 mm × 9–11 mm × 4–6.5 mm, slightly flattened, glabrous, knobbed at one side in the middle.
Strychnos comprises about 200 species: about 60 species in Asia, 65 in America and 75 in Africa. Strychnos afzelii belongs to the section Breviflorae. Another spiny species from West and northern Central Africa is Strychnos congolana Gilg which belongs to section Spinosae. In Côte d’Ivoire the leaf pulp is applied to treat snakebites. Ground roots of Strychnos congolana and seeds of Aframomum melegueta K.Schum. made into a paste are administered as a suppository to treat dysmenorrhoea. The paste is also used as an aphrodisiac.
Ecology
Strychnos afzelii occurs on river banks or in moist localities in periodically inundated rainforest, including secondary forest and coastal swamp forest, from sea-level up to 700 m altitude.
Genetic resources and breeding
Strychnos afzelii is widespread and does not seem to be in danger of genetic erosion.
Prospects
It seems likely that Strychnos afzelii will remain of limited use only, unless more elaborate tests on the antibacterial and antifungal activities of the stem bark reveal potential for developing phytomedicines.
Major references
• Abbiw, D.K., 1990. Useful plants of Ghana: West African uses of wild and cultivated plants. Intermediate Technology Publications, London and Royal Botanic Gardens, Kew, Richmond, United Kingdom. 337 pp.
• Bisset, N.G., 1970. The African species of Strychnos. Part I. The ethnobotany. Lloydia 33(2): 201–243.
• 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.
• 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.
Other references
• Adjanohoun, E.J. & Aké Assi, L., 1979. Contribution au recensement des plantes médicinales de Côte d’Ivoire. Centre National de Floristique, Abidjan, Côte d’Ivoire. 358 pp.
• Bouquet, A. & Debray, M., 1974. Plantes médicinales de la Côte d’Ivoire. Travaux et Documents No 32. ORSTOM, Paris, France. 231 pp.
• Frédérich, M., Tits, M. & Angenot, L., 2003. Indole alkaloids from Strychnos species and their antiplasmodial and cytotoxic activities. Chemistry of Natural Compounds 39(6): 513–519.
• Melo, M.F., Santos, C.A., Chiappeta, A.A., de Mello, J.F. & Mukherjee, R., 1987. Chemistry and pharmacology of a tertiary alkaloid from Strychnos trinervis root bark. Journal of Ethnopharmacology 19(3): 319–325.
• Tra Bi, F.H., Kouamé, N.F., Traoré, D. & van der Maesen, L.J.G., 1999. Les lianes dans l’entretien bucco-dentaire en Côte d’Ivoire. Revue de Médecines et Pharmacopées Africaines 13: 65–70.
• Tra Bi, F.H., Kouamé, F.N. & Traoré, D., 2005. Utilisation of climbers in two forest reserves in West Côte d’Ivoire. In: Bongers, F., Parren, M.P.E. & Traoré, D. (Editors). Forest climbing plants of West Africa. Diversity, ecology and management. CABI Publishing, Wallingford, United Kingdom. pp. 167–181.
• Verpoorte, R., Groenink, H. & Baerheim Svendsen, A., 1980. Minor alkaloids and sterols in Strychnos afzelii. Planta Medica 38: 388–390.
• Verpoorte, R., Kode, E.W., van Doorne, H. & Baerheim Svendsen, A., 1978. Antimicrobial effect of the alkaloids from Strychnos afzelii Gilg. Planta Medica 33: 237–242.
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 afzelii Gilg. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.