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Euphorbia quinquecostata Volkens

Protologue
Notizbl. Bot. Gart. Berlin-Dahlem 2: 266 (1899).
Family
Euphorbiaceae
Vernacular names
Mchorongo (Sw).
Origin and geographic distribution
Euphorbia quinquecostata occurs in Kenya, Tanzania and Mozambique.
Uses
In Tanzania a stem infusion is given to children to expel intestinal worms; it is also taken to treat stomach-ache and is externally applied to heal wounds. The latex is rubbed into the skin in case of pain in the ribs, but this should be done with caution as it causes blisters.
In the Tanga region of Tanzania the latex is used as bird lime.
Properties
An ethyl acetate extract of the wood of Euphorbia quinquecostata using a phorbol dibutyrate receptor-binding assay system as a monitor yielded 4 inhibitory compounds; 2 were ingenane ester derivatives, 17-hydroxyingenol 20-hexadecanoate and ingenol 20-hexadecanoate, and the other 2 were ent-atisane derivatives. Also isolated from this extract were constituents inactive in this bioassay, including xanthoxylin, 6-hydroxy-7-methoxycoumarin (isoscopoletin), lupeol acetate, β-sitosterol, sitosterol-β-D-glucopyranoside, 6,7,8-trimethoxycoumarin, 3,4-dimethoxycinnamaldehyde, N-butylaniline and vanillin. A later isolated ent-isopimarane-type diterpene and a dihydrobenzofuran neolignan were inactive in assays for the induction of quinone reductase in hepatoma cells and for the inhibition of the transformation of murine cells, but 3,4-dimethoxycinnamaldehyde was significantly active in these assays.
Botany
Monoecious, succulent small tree up to 10(–15) m tall with abundant latex; bole simple, up to 50 cm in diameter, with loosely spiraled rows of spines and scars of fallen branches; bark grey-brown, flaking; primary branches 2–4 m long, with whorls of secondary branches, directing upwards, forming a rounded crown; terminal branches fleshy, (3–)5(–6)-angled, 2–4(–7) cm in diameter, constricted at irregular intervals into oblong segments 5–15 cm long, margins of angles straight to toothed, with teeth 5–15 mm apart; spine shields oblong-triangular, c. 1.5 mm × 2 mm, with 1 pair of spines 2–8(–10) mm long. Leaves at the end of branches, in 4 rows, sessile; stipules absent; blade deltoid, c. 2 mm × 2 mm, soon falling. Inflorescence an axillary cyme, 1–3 together in a horizontal row, consisting of clusters of flowers, each cluster called a ‘cyathium’, crowded at the end of branches; peduncle 2–3 mm long, branches 2, short; bracts 2, c. 2 mm long; cyathia c. 2.5 mm × 4 mm, with a cup-shaped involucre, lobes c. 1 mm long, glands 5, transversely oblong, c. 1 mm × 2 mm, golden-yellow, each involucre containing 1 female flower surrounded by many male flowers. Flowers unisexual; male flowers sessile, perianth absent, stamen c. 4 mm long; female flowers with pedicel c. 7 mm long in fruit, perianth 3-lobed, ovary superior, glabrous, 3-celled, styles 3, c. 1 mm long, fused at base, apex 2-fid. Fruit a deeply 3-lobed capsule c. 4.5 mm × 7 mm, fleshy, 3-seeded. Seeds almost globose, c. 2.5 mm × 2 mm, grey-mottled, smooth.
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 quinquecostata belongs to section Euphorbia, a large group which is characterized by succulent, usually angular stems, stipules modified into small spines (or absent), a spine shield with an additional pair of spines (sometimes fused into a single spine), axillary inflorescences and seeds without a caruncle.
Some other species from this section are medicinally used in tropical Africa. Euphorbia robecchii Pax occurs in Ethiopia, Somalia, Kenya and Tanzania. In Somalia the latex is widely used in the treatment of cattle diseases, including foot rot, foot abscesses, mange, ringworm and ticks. In Tanzania dried stem bark is boiled with butter and coffee beans, and the decoction is rubbed onto inflamed lymph nodes. The latex is applied to the skin of camels to treat contagious skin necrosis.
Euphorbia teke Schweinf. ex Pax (synonym: Euphorbia tisserantii A.Chev. & Sillans) occurs from the Central African Republic and southern Sudan south to Congo and DR Congo and east to Uganda and Tanzania. In the Central African Republic the latex is boiled with an egg and taken as a strong purgative to treat gonorrhoea.
Ecology
Euphorbia quinquecostata occurs on rocky hillsides, and is usually the dominant tree in mixed deciduous woodland, at 600–1250 m altitude.
Genetic resources and breeding
There are no signs that Euphorbia quinquecostata is threatened by genetic erosion. All succulent Euphorbia spp. are listed in CITES appendix 2.
Prospects
Euphorbia quinquecostata yields several interesting compounds, which merit further research into their anticancer activities.
Major references
• Carter, S. & Radcliffe-Smith, A., 1988. Euphorbiaceae (part 2). In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. pp. 409–597.
• Elia, J., 2007. Use of herbarium information in plant conservation strategies: case study concerning a herbarium survey of Euphorbia quinquecostata in Tanzania. In: PROTA, 2007. Information, programme, summaries. Second PROTA / CTA International Workshop and Investor’s Forum, 24–26 September, Nairobi, Kenya. pp. 75–76.
• Kokwaro, J.O., 1993. Medicinal plants of East Africa. 2nd Edition. Kenya Literature Bureau, Nairobi, Kenya. 401 pp.
• Mbwambo, Z.H., Lee, S.K., Mshiu, E.N., Pezzuto, J.M. & Kinghorn, A.D., 1996. Constituents from the stem wood of Euphorbia quinquecostata with phorbol dibutyrate receptor-binding inhibitory activity. Journal of Natural Products 59(11): 1051–1055.
Other references
• Catley, A. & Mohammed, A.A., 1996. Ethnoveterinary knowledge in Sanaag region, Somaliland (Part 11): notes on local methods of treating and preventing livestock disease. Nomadic Peoples 38: 1–12.
• ITDG & IIRR, 1996. Ethnoveterinary medicine in Kenya. A field manual of traditional animal health care practice. Intermediate Technology Development Group and International Institute of Rural Reconstruction, Nairobi, Kenya. 226 pp.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Su, B.N., Park, E.J., Mbwambo, Z.H., Santarsiero, B.D., Mesecar, A.D., Fong, H.H.S., Pezzuto, J.M. & Kinghorn, D.A., 2002. New chemical constituents of Euphorbia quinquecostata and absolute configuration assignment by a convenient Mosher ester procedure carried out in NMR tubes. Journal of Natural Products 65(9): 1278–1282.
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. Euphorbia quinquecostata Volkens. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.