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Maprounea membranacea Pax & K.Hoffm.

Protologue
in H.G.A. Engler, Pflanzenr. IV, 147, 5 (Heft 52): 178 (1912).
Family
Euphorbiaceae
Origin and geographic distribution
Maprounea membranacea occurs from Nigeria east to the southern part of the Central African Republic and DR Congo and south to Angola.
Uses
In Congo and northern DR Congo pieces of root bark or stem bark, laced with honey or sugar, are used as a violent purgative to treat constipation, ascites and generalised oedema, intestinal worms, female sterility and an irregular menstrual cycle. A cold water maceration of bark scrapings is given to constipated babies. In Gabon the dried powdered leaves are used to cicatrise wounds, especially circumcision wounds. In Congo a bark infusion is used as a vaginal douche to treat vaginitis and problems of the uterus, and rolled-up leaves or leaf pulp may be placed as a vaginal suppository for the same purpose. Externally, an ointment of the powdered bark in palm oil is applied to treat leprosy, smallpox, scabies and other skin infections. In northern DR Congo a leaf decoction is used to wash infected eyes. A root decoction is drunk to treat syphilis. In Gabon the bruised young stems are laid in houses to repel cockroaches.
In Gabon the wood is used to make mortars.
Properties
The stem bark contains small amounts of pentacyclic triterpenes and derivatives, which do not seem to have biological activity. The stem bark also contains cucurbitacin A and derivatives, diterpenes, phorbol esters of the daphnane type, of which several exhibited potent inhibitory activity against HIV-1 reverse transcriptase.
Botany
Monoecious or sometimes dioecious small to medium-sized tree up to 25 m tall; bole up to 30(–50) cm in diameter; bark longitudinally fissured, pinkish grey. Leaves alternate, simple and entire; stipules ovate, c. 0.5 mm long; petiole 0.5–2 cm long; blade elliptical to ovate, 2.5–10 cm × 1.5–5 cm, base unequal, one side cuneate and other side cordate, apex rounded, glabrous with sparse glandular dots, pinnately veined with 6–10 pairs of lateral veins. Inflorescence a terminal raceme up to 3.5 cm long, on short lateral shoots, with male flowers in an apical, oblong, compact, reddish spike, 4–9 mm × 3–6 mm and 1–5 female flowers at base, green; bracts up to 1.5 mm long. Flowers unisexual, petals absent; male flowers with pedicel 1–1.5 mm long, calyx lobes 2–3, c. 0.5 mm long, red, stamens 2, fused into a staminal column 1–1.5 mm long, white; female flowers with pedicel 0.5–1 cm long, extending to 3 cm long in fruit, calyx lobes 3, c. 1 mm long, ovary superior, ovoid, c. 1.5 mm in diameter, 3(–4)-celled, smooth, styles 3, fused at base, reflexed at apex, persistent. Fruit a globose capsule 5–7 mm in diameter, smooth, green, later red or brown, 3-seeded. Seeds oblong, 4.5–5.5 mm × 3.5–4 mm, usually smooth, black, caruncle 2–3 mm long, the 2 lobes covering up to half the seed, orange or bright red.
Maprounea comprises 4 species, 2 of which occur in tropical Africa and 2 in South America.
Ecology
Maprounea membranacea occurs in periodically inundated forest, wet forest and secondary forest on dry soil, at low altitudes.
Genetic resources and breeding
Maprounea membranacea is common in its area of distribution and therefore not threatened by genetic erosion.
Prospects
The stem bark and root bark of Maprounea membranacea have antibacterial and anthelmintic uses, but no research has been done to identify the compounds responsible for these activities, or their pharmacological properties. The pentacyclic triterpenes isolated show interesting anti-HIV activity, which merits further research.
Major references
• Beutler, J.A., Kashman, Y., Tischler, M., Cardellina, J.H., Gray, G.N., Currens, M.J., Wall, M.E., Wani, M.C. & Boyd, M.R., 1995. A reinvestigation of Maprounea triterpenes. Journal of Natural Products 58(7): 1039–1056.
• 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.
• 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
• Beutler, J.A., Alvarado, A.B., McCloud, T.G. & Cragg, G.M., 1989. Distribution of phorbol ester bioactivity in the Euphorbiaceae. Phytotherapy Research 3(5): 188–192.
• Paris, R.R. & Tessier, A.M., 1972. Présence de substances du groupe des cucurbitacines chez diverses Euphorbiacées toxiques africaines, notamment chez Maprounea membranacea Pax et K.Hoffm. Comptes Rendus Hebdomadaires des Séances de l’Académie des Sciences, Serie D, Sciences Naturelles 274(2): 321–323.
• Raponda-Walker, A. & Sillans, R., 1961. Les plantes utiles du Gabon. Paul Lechevalier, Paris, France. 614 pp.
• Tessier, A.M., 1975. Etude de quelques Euphorbiacées toxiques africaines: Maprounea africana Muell. Arg., Maprounea membranacea Pax et K. Hoffm. et Spondianthus preussii Engl. Thèse Pharmacologique, Université de Paris 5, Paris, France. 300 pp.
• Tessier, A.M. & Paris, R.R., 1978. Study of some African toxic Euphorbiaceae containing cucurbitacins. Toxicological European Research 1(5): 329–336.
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., 2008. Maprounea membranacea Pax & K.Hoffm. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.