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Euphorbia convolvuloides Hochst. ex Benth.

Protologue
Hook., Niger Fl.: 499 (1849).
Family
Euphorbiaceae
Origin and geographic distribution
Euphorbia convolvuloides occurs in the drier parts of West Africa, from Mauritania and Senegal east to Sudan.
Uses
In Senegal and Ghana an infusion of the plant is taken to treat urethritis and sexually transmitted diseases, while in Côte d’Ivoire an infusion is applied as eye drops to treat eye problems. In Nigeria crushed leaves, mixed with palm oil, are applied to dry up the rashes associated with measles, chickenpox and formerly smallpox. The crushed leaves are taken to treat diarrhoea as they have an astringent effect, and an infusion of the dried leaves is taken against dysentery. In contrast, an infusion of the whole plant is taken orally or as an enema for its laxative effects. An extract of the plant is taken to treat coughs, a sore throat, asthma and bronchitis. The vapour of latex in hot water is also inhaled to treat coughs and bronchitis. The pulp of fresh leaves mixed with those of Citrullus colocynthis (L.) Schrad., and sometimes with other plants, is applied to the breasts or given in infusion to increase milk production and quality of the milk. In Nigeria scorpion stings and snakebites are said to be prevented if the plant is chewed and swallowed, and a mixture of the plant, saliva and the sap of Calotropis procera (Aiton) R.Br. is rubbed on the hands. The latex is considered an antidote for scorpion stings. The plant is also considered narcotic and is used magically. In Senegal a plant infusion is given to cattle to drink to treat urinary infections.
Euphorbia convolvuloides is generally browsed by livestock.
Properties
The aerial parts have an astringent effect due to the presence of tannins.
Botany
Monoecious, erect, hairy, annual herb up to 40 cm tall; branches drooping at the tips, often reddish. Leaves opposite, distichous, simple; stipules minute; petiole up to 1 mm long; blade oblong to lanceolate, 2–4 cm × 0.5–1.5 cm, base slightly unequal, cuneate, apex acute, margins minutely toothed. Inflorescence a terminal or axillary cluster of flowers, called a ‘cyathium’, several cyathia densely clustered together, pink; cyathia almost sessile, c. 1 mm × 1 mm, with a cup-shaped involucre, densely white-hairy, lobes triangular, minute, hairy, glands 4, tiny, round, with or without appendages, pink with white rim, each involucre containing 1 female flower surrounded by many male flowers. Flowers unisexual; male flowers sessile, bracteoles linear, perianth absent, stamen c. 0.5 mm long; female flowers with pedicel c. 1.5 mm long, reflexed in fruit, perianth a rim, ovary superior, densely hairy, 3-celled, styles 3, minute. Fruit a hairy 3-lobed capsule c. 2 mm in diameter, 3-seeded. Seeds ovoid, c. 1.5 mm long, acutely 4–5-angled, whitish or pale reddish, without caruncle. Seedling with epigeal germination; cotyledons almost sessile, elliptical; epicotyl absent.
Euphorbia comprises about 2000 species and has a worldwide distribution, with at least 750 species occurring in continental Africa and about 150 species in Madagascar and the Indian Ocean islands. Euphorbia convolvuloides belongs to subgenus Chamaesyce section Chamaesyce, a group of annual or sometimes perennial herbs with obvious stipules, further characterized by a main stem aborting at the seedling stage. The plant thus consists of an expanded dichotomously branching umbel-like inflorescence, with the floral bracts appearing as normal leaves, cyathia solitary or up to 5 grouped together in congested leafy cymes, 4 involucral glands with petal-like appendages or entire and conical seeds without a caruncle. Euphorbia kilwana N.E.Br. (synonym: Euphorbia convolvuloides var. integrifolia Pax) occurs in Tanzania, Malawi, Zimbabwe and Mozambique and closely resembles Euphorbia convolvuloides. Euphorbia forskalii J.Gay (synonym: Euphorbia aegyptiaca Boiss.) also belongs to section Chamaesyce and occurs on clay soils throughout tropical West Africa east to Somalia, and from northern Africa east to the Arabian Peninsula and Turkey. It also occurs in Namibia. In Nigeria extracts of Euphorbia forskalii are taken as a purgative to treat tapeworm; the latex is applied to warts, sores, guinea-worm and jiggers. In Nigeria and Sudan the plant is pounded with a little water and applied to the head and neck to treat headache, bone fractures or traumatic swellings. In Sudan the latex is applied to the breasts as a galactagogue. Sheep and goats browse the plants. Petroleum-ether extracts of the whole plant show significant activity against freshwater snails.
Several other Euphorbia spp. not belonging to section Chamaesyce are used medicinally in West Africa. Euphorbia baga A.Chev. has a rounded tuber and short thickened stems with tufts of lanceolate, acute leaves at the apex. It occurs from Côte d’Ivoire and Mali east to Nigeria and also in Sudan. In Sudan the latex or crushed plant is used as fish poison. Euphorbia kerstingii Pax occurs from Togo east to Cameroon. It has annual stems up to 16 cm long arising from a woody rootstock. The Kotokoli people from Togo use a plant extract to harden the fontanel of newborn babies.
Ecology
Euphorbia convolvuloides occurs in savanna, waste places and along roadsides, sometimes as a weed in crops, usually on sandy soil.
Management
Euphorbia convolvuloides can be collected during the rainy season, and dried for future use.
Genetic resources and breeding
Euphorbia convolvuloides is relatively common in its area of distribution and there are no signs that it is threatened by genetic erosion.
Prospects
Euphorbia convolvuloides has many local medicinal uses but will remain of local importance only, unless chemical and pharmacological research can confirm its medicinal value.
Major references
• Adjanohoun, E.J., Adjakidjè, V., Ahyi, M.R.A., Aké Assi, L., Akoègninou, A., d’Almeida, J., Apovo, F., Boukef, K., Chadare, M., Cusset, G., Dramane, K., Eyme, J., Gassita, J.N., Gbaguidi, N., Goudote, E., Guinko, S., Houngnon, P., Lo, I., Keita, A., Kiniffo, H.V., Kone-Bamba, D., Musampa Nseyya, A., Saadou, M., Sodogandji, T., De Souza, S., Tchabi, A., Zinsou Dossa, C. & Zohoun, T., 1989. Contribution aux études ethnobotaniques et floristiques en République Populaire du Bénin. Agence de Coopération Culturelle et Technique, Paris, France. 895 pp.
• Brown, N.E., Hutchinson, J. & Prain, D., 1909–1913. Euphorbiaceae. In: Thiselton-Dyer, W.T. (Editor). Flora of tropical Africa. Volume 6(1). Lovell Reeve & Co., London, United Kingdom. pp. 441–1020.
• Burkill, H.M., 1994. The useful plants of West Tropical Africa. 2nd Edition. Volume 2, Families E–I. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 636 pp.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Stäuble, N., 1986. Etude ethnobotanique des Euphorbiacées d’Afrique de l’Ouest. Journal of Ethnopharmacology 16: 23–103.
Other references
• Berhaut, J., 1975. Flore illustrée du Sénégal. Dicotylédones. Volume 3. Connaracées à Euphorbiacées. Gouvernement du Sénégal, Ministère du Développement Rural et de l’Hydraulique, Direction des Eaux et Forêts, Dakar, Senegal. 634 pp.
• Bouquet, A. & Debray, M., 1974. Plantes médicinales de la Côte d’Ivoire. Travaux et Documents No 32. ORSTOM, Paris, France. 231 pp.
• Iwu, M.M., 1993. Handbook of African medicinal plants. CRC Press, Boca Raton, Florida, United States. 464 pp.
• Keay, R.W.J., 1958. Euphorbiaceae. In: Keay, R.W.J. (Editor). Flora of West Tropical Africa. Volume 1, part 2. 2nd Edition. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. pp. 364–423.
• Le Bourgeois, T. & Merlier, H., 1995. Adventrop. Les adventices d’Afrique soudano-sahélienne. CIRAD-CA, Montpellier, France. 637 pp.
• Manu, T.N.J., 2002. Medicinal plants used in the treatment of sexually transmitted diseases (STDS). B.Pharm. thesis, Faculty of Pharmacy, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. 63 pp.
Author(s)
O.M. Grace
PROTA Country Office United Kingdom, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, United Kingdom


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:
Grace, O.M., 2008. Euphorbia convolvuloides Hochst. ex Benth. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.