Prota 11(1): Medicinal plants/Plantes médicinales 1
Bot. Jahrb. Syst. 17: 572 (1893).
2n = 44
Origin and geographic distribution
Strychnos afzelii occurs from Senegal east to Nigeria.
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.
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.
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.
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.
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.
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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.