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Croton haumanianus J.Léonard

Protologue
Bull. Agric. Congo Belge 48: 79 (1957).
Family
Euphorbiaceae
Origin and geographic distribution
Croton haumanianus has been recorded in southern Cameroon, Equatorial Guinea, Congo and DR Congo.
Uses
In Congo an infusion of the grated, bitter, fresh bark is commonly taken as a purgative and diuretic. The grated bark is mixed with palm oil and is applied to the body to treat rheumatism, headache, pain in the side, oedema of the legs and abscesses. Sometimes mashed leaves are mixed with the grated bark. A leaf or bark decoction is taken to treat gonorrhoea, urinary infections, worms, headache, constipation, starting hernia, heartburn, oedema, rheumatism and painful urination. A decoction or infusion is also applied as an enema as a purgative. A bark infusion is taken to treat hypertension and epilepsy. Pregnant women with a history of repeated spontaneous abortions take a spoonful of the liquid obtained from crushed seeds in water to prevent abortion. In DR Congo small amounts of bark decoction, alone or in combination with other plants, are drunk to treat gonorrhoea and rheumatism. A preparation of stem bark, leaves or fruits is eaten as an aphrodisiac. Mashed stem bark and fruits are used to kill rats and in the preparation of arrow poison. The plant is used in ceremonies to chase away bad spirits, and to restore health when taboos have been broken.
The wood is used in carpentry. Croton haumanianus is frequently planted as a shade plant in coffee and cacao plantations.
Properties
The stem bark contains several diterpenes including crotocorylifuran, a clerodane-type diterpenoid, and crotohaumanoxide, a crotofolane-type diterpenoid.
Botany
Monoecious small to medium-sized tree up to 15(–35) m tall, densely scaly and stellate hairy; bole cylindrical, up to 40(–100) cm in diameter; outer bark longitudinally fissured, brownish green, inner bark yellowish orange and whitish, scented, exudate brown and sticky; crown light. Leaves alternate, simple and entire; stipules filiform, 1–15 mm long, usually with basal, filiform appendages, persistent; petiole 1.5–12 cm long; blade elliptical to ovate-elliptical, 4–19.5 cm × 2–9.5 cm, base rounded to cordate, basal glands 2(–4), apex acute to acuminate, whitish beneath. Inflorescence a terminal raceme 3–21 cm long, with many male flowers at apex and few female flowers at base. Flowers unisexual, 5-merous, regular, white; pedicel 1–5 mm long; sepals elliptical, 3.5–4.5 mm long; male flowers with elliptical petals 2.5–4 mm long, hairy on both sides, stamens 23–34, free; female flowers with linear petals 3–3.5 mm long, hairy on both sides, ovary superior, rounded, densely hairy, 3-celled, styles 3, 3–4 times deeply 2-fid. Fruit an almost globular, thick-walled drupe, 2–2.5 cm in diameter, indehiscent, upper part slightly 3-lobed, 3-seeded. Seeds ellipsoid, c. 7 mm × 5 mm, whitish. Seedling with epigeal germination.
Croton comprises about 1200 species and occurs throughout the warmer regions of the world. It is best represented in the Americas; about 65 species occur in continental Africa and about 125 in Madagascar. Several other medicinally used Croton species occur in Central Africa. In Congo an infusion of the fruits of Croton draconopsis Müll.Arg. is taken as a purgative and vermifuge; the leaves and root bark are sometimes used similarly. In Congo Croton mayumbensis J.Léonard is often used instead of Croton haumanianus. A bark decoction is used as nose drops to treat sinusitis and colds. In Gabon a bark decoction of Croton mayumbensis or Croton oligandrus Pierre ex Hutch. is drunk to treat colic. Bark powder is sniffed to treat nasal tumours and it is externally applied to treat scabies. The wood of Croton oligandrus is used in carpentry. In Gabon the stem bark of Croton tchibangensis Pellegr. is commonly used as a fish poison.
Ecology
Croton haumanianus occurs in secondary forest and regrowth of lowland rainforest, up to 1000(–1200) m altitude.
Genetic resources and breeding
Croton haumanianus is very common in its distribution area and not likely to be threatened by genetic erosion.
Prospects
Croton haumanianus has many local medicinal uses. It is poisonous and should be used with caution. Despite the many uses, not much pharmacological research has been undertaken on this species.
Major references
• Adjanohoun, E.J., Ahyi, A.M.R., Aké Assi, L., Baniakina, J., Chibon, P., Cusset, G., Doulou, V., Enzanza, A., Eymé, J., Goudoté, E., Keita, A., Mbemba, C., Mollet, J., Moutsamboté, J.-M., Mpati, J. & Sita, P. (Editors), 1988. Médecine traditionnelle et pharmacopée - Contribution aux études ethnobotaniques et floristiques en République Populaire du Congo. Agence de Coopération Culturelle et Technique, Paris, France. 606 pp.
• Bouquet, A., 1969. Féticheurs et médecines traditionnelles du Congo (Brazzaville). Mémoires ORSTOM No 36. Office de la Recherche Scientifique et Technique Outre-Mer. Paris, France. 282 pp.
• Léonard, J., 1962. Euphorbiaceae. In: Robyns, W., Staner, P., Demaret, F., Germain, R., Gilbert, G., Hauman, L., Homès, M., Jurion, F., Lebrun, J., Vanden Abeele, M. & Boutique, R. (Editors). Flore du Congo belge et du Ruanda-Urundi. Spermatophytes. Volume 8, 1. Institut National pour l’Étude Agronomique du Congo belge, Brussels, Belgium. 214 pp.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
Other references
• Raponda-Walker, A. & Sillans, R., 1961. Les plantes utiles du Gabon. Paul Lechevalier, Paris, France. 614 pp.
• Tchissambou, L., Chiaron, A., Riche, C. & Khuong Huu, F., 1990. Crotocorylifuran and crotohaumanoxide, new diterpenes from Croton haumanianus J.Léonard. Tetrahedron 46(15): 5199–5202.
• 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.
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. Croton haumanianus J.Léonard. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.