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Euphorbia pseudograntii Bruyns

Protologue
Taxon 55(2): 414 (2006).
Family
Euphorbiaceae
Chromosome number
2n = 36
Synonyms
Synadenium grantii Hook.f. (1867).
Vernacular names
African milkbush, coat-of-many-colours (En). Kinyunywa (Sw).
Origin and geographic distribution
Euphorbia pseudograntii occurs from Ethiopia south to eastern DR Congo and Tanzania and probably also in Malawi, Zambia and Zimbabwe.
Uses
In DR Congo the latex of Euphorbia pseudograntii is applied to warts, and leaf sap to treat cardiac problems. The powder from dried young stems mixed with salt is licked to soothe cough. In Rwanda and Burundi the latex is applied to cure syphilis. In Burundi several drops of latex from warmed leaves are taken to expel intestinal parasites and sometimes tapeworm. In Uganda and Tanzania the latex is applied to abscesses to mature them. Leaf sap is taken to treat excessive menstruation. In East Africa leaf preparations are externally applied to psoriasis and impetigo. A decoction of the stem bark or the latex is taken to expel a retained placenta, whereas a leaf decoction is drunk as an abortifacient. Pulverized leaves are rubbed into scarifications to treat backache. Leaf ash is taken in water to treat a sore throat. Pulverized leaves are applied to wounds. A root extract or sap from the crushed stem is used as ear drops to treat earache. In Tanzania a root preparation is used as a malaria remedy.
In Kenya the roots, in a mixture with parts of other plants, are boiled and the liquid is given to drink to cattle suffering from anthrax or blackquarter. The latex is also used as a blistering remedy on swollen glands caused by East Coast Fever in cattle.
In DR Congo the latex of young stems and leaves is used for tattooing. The latex can be fatal if ingested and is also used as a fish poison. In Rwanda the latex is an ingredient of arrow poison. In Kenya and Tanzania the plant is sometimes used for criminal purposes.
Euphorbia pseudograntii is sometimes cultivated as a greenhouse plant in temperate regions or as a garden plant in Kenya.
Properties
Euphorbia pseudograntii has long been recognized as being very toxic and irritant. Contact of the latex with the skin or mucous membranes will cause a burning sensation, dermatitis and blisters. Symptoms may not be developed immediately and can be delayed for hours.
The latex of Euphorbia pseudograntii yields several diterpene esters of the tigliane type derived from 4-desoxyphorbol, of which 4-deoxyphorbol-13-phenylacetate-12-tigliate showed very strong skin irritant activity, with an ID50 of 0.000064 nMol/ear in mice. As a comparison, the standard irritant TPA (12-O-tetradecanoylphorbol-13-acetate) has an ID50 of 0.016 nMol/ear. The tumour-promoting activity of the isolated diester was found to be low. The other esters were relatively unstable and had only slight irritant activities. Subcutaneous injection of 0.5–1 ml latex into guinea pigs resulted in 40% mortality after 48–72 hours, the surviving animals developed severe oedema, skin lesions and necrosis. An ethanolic extract of the latex induced significant, dose-dependent reversible hypothermia when injected intraperitoneally in rats and rabbits. In anaesthetized dogs, a slight rise in blood pressure with diuresis was induced by low doses, whereas high doses caused a severe to fatal drop in blood pressure, and several other effects.
The triterpenoids euphol, euphorbol and tirucallol were isolated from the acetone extract of the latex. Intravenous administration of euphol caused hypotensive activity in normotensive anaesthetized dogs and rats. The LD50 is 1.5 g/kg in mice intraperitoneally and more than 2 g/kg orally.
The latex also contains rubber (cis-1,4 linked polyisoprene) and ionol, an antioxidant which could play a role in the stabilization of Euphorbia pseudograntii latex. Furthermore, several acetylcholinesterase isozymes and proteolytic enzymes were purified from the latex, one of them with fibrinolytic and fibrinogenolytic properties, as well as several lectins, one of them exhibiting maximum agglutinating activity towards human O-group erythrocytes.
The acetone extract of dried latex showed high molluscicidal activity against the freshwater snails Biomphalaria alexandrina and Bulinus truncatus. The latex also has some acaricidal properties; in a trial in Uganda, the extract killed 62% of ticks. The latex showed significant nematicidal activity against Meloidogyne javanica infecting sunflower under greenhouse conditions.
Description
Monoecious, rather succulent shrub or small bushy tree up to 5(–10) m tall; stems cylindrical, older stems pale grey, with prominent leaf scars on green stems and copious latex. Leaves arranged spirally, simple and entire; stipules modified into small brown glands; petiole up to 8 mm long; blade elliptical to oblanceolate, up to 15 cm Χ 6(–8) cm, base long-cuneate, apex obtuse to short-acuminate, fleshy, margin curled down, nearly glabrous, pinnately veined, midvein prominent below, rounded, green or sometimes tinged red beneath. Inflorescence a lax axillary cyme, consisting of clusters of flowers, each cluster called a ‘cyathium’; peduncle up to 5 cm long, short-hairy, branches 1–3 cm long; bracts 2, c. 4 mm Χ 4 mm, short-hairy, reddish green, persistent; cyathia c. 3 mm Χ 6.5 mm, with a funnel-shaped involucre, bright red, 5-lobed with lobes c. 2 mm Χ 2 mm, with glandular rim c. 1 mm wide, deeply furrowed, red, each cyathium containing 1 female flower surrounded by male flowers. Flowers unisexual; male flowers sessile with linear bracteoles, fringed, with red tips, perianth absent, stamen c. 4 mm long, shortly exserted; female flowers with pedicel up to 5(–9) mm in fruit, perianth a 3-lobed rim, ovary superior, densely short-hairy, 3-celled, styles 3, c. 2 mm long, fused at base, bifid at apex. Fruit a 3-lobed capsule c. 7 mm Χ 8 mm, short-hairy, red, 3-seeded. Seeds ovoid, c. 2.5 mm Χ 2 mm, pale brownish grey, minutely tuberculate, caruncle rudimentary.
Other botanical information
Euphorbia comprises about 2000 species and has a worldwide distribution. Synadenium (about 15 species in continental Africa) has classically been kept separate from Euphorbia, mainly because the glands of the cyathia form a ring, whereas the glands of Euphorbia species are separate or only touching. However, recent molecular analyses found Synadenium to be nested within Euphorbia section Monadenium, and therefore it is now included in Euphorbia. Euphorbia pseudograntii Bruyns is an invalid name as Euphorbia pseudograntii Pax already existed for another species, a fact overlooked by Bruyns. This is in the process of being corrected. The specimens of Euphorbia pseudograntii Bruyns in southern Africa might belong to Euphorbia kirkii (N.E.Br.) Bruyns (synonym: Synadenium kirkii N.E.Br.), which has hairy leaf margins and lower midvein, a yellow glandular involucre ring and seeds with an obvious caruncle.
The name Synadenium grantii is internationally used for an ornamental plant, but this usually concerns Euphorbia bicompacta Bruyns. Especially Euphorbia bicompacta var. rubra (S.Carter) Bruyns is a widespread ornamental and hedge plant in subtropical gardens and a pot plant in Europe and the United States. It mainly differs from Euphorbia pseudograntii by having broadly obovate, sparsely toothed leaves, a prominent, sharp midvein below, blade usually with a red blotch below, and short, reddish-purple inflorescences. Euphorbia bicompacta occurs wild or cultivated in Ethiopia, Kenya, Rwanda and Tanzania. In Kenya, plant sap is used for treating East Coast fever in cattle. A decoction of its leaves and stem bark is given to drink to cattle to control ticks. Euphorbia triangolensis Bruyns (synonym: Synadenium angolense N.E.Br.) occurs in Malawi, Zambia and Angola. In Angola a root infusion is drunk to treat pain in the hips and madness. An infusion of unspecified plant parts is taken to treat stomach-ache, dropsy, stitch, urogenital problems, excessive menstruation, tuberculosis and cardiac palpitations. The latex is used as fish poison.
Growth and development
In cultivation Euphorbia pseudograntii is moderately slow-growing, growing faster in warm tropical conditions with abundant rainfall. Under garden conditions at high altitudes, it can reach 3 m in height in 5 years.
Ecology
Euphorbia pseudograntii is xerophytic and thrives on rocky hills with dry open woodland in the east African uplands, at 900–2100 m altitude and an annual rainfall of 600–900 mm.
Propagation and planting
Euphorbia pseudograntii is easily propagated from seed, stem cuttings and root cuttings. Fresh cuttings should be dipped in charcoal dust to stop the leaking of latex and should be planted in sand to root.
Diseases and pests
Excessive rainfall and cold conditions cause the stem to rot.
Handling after harvest
One should take great care to avoid latex falling on skin, lips and eyes, and gloves are recommended for handling.
Genetic resources
Euphorbia pseudograntii is relatively common in its distribution area and there are no signs that it is threatened by genetic erosion. As a (semi-)succulent Euphorbia species, its trade is controlled under CITES appendix 2.
Prospects
The use of Euphorbia pseudograntii as a medicinal plant is not recommended because of its very toxic latex. The tigliane diterpene esters isolated from the latex have not yet yielded interesting pharmacological compounds. The enzymes and lectins isolated from the latex might have some potential in future, but more research is required.
Major references
• Bruyns, P.V., Mapaya, R.J. & Hedderson, T., 2006. A new subgeneric classification for Euphorbia (Euphorbiaceae) in southern Africa based on ITS and psbA-trnH sequence data. Taxon 55(2): 397–420.
• Carter, S., 1987. Taxonomic changes in Synadenium (Euphorbiaceae) from East Africa. Kew Bulletin 42(3): 667–671.
• 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.
• 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., 1996. African ethnobotany: poisons and drugs. Chapman & Hall, London, United Kingdom. 941 pp.
• Rajesh, R., Nataraju, A., Gowda, C.D.R., Frey, B.M., Frey, F.J. & Vishwanath, B.S., 2006. Purification and characterization of a 34-kDa, heat stable glycoprotein from Synadenium grantii latex: action on human fibrinogen and fibrin clot. Biochimie 88(10): 1313–1322.
• Steinmann, V.W. & Porter, J.M., 2002. Phylogenetic relationships in Euphorbieae (Euphorbiaceae) based on its and ndhF sequence data. Annals of the Missouri Botanical Garden 89(4): 453–490.
• Watt, J.M. & Breyer-Brandwijk, M.G., 1962. The medicinal and poisonous plants of southern and eastern Africa. 2nd Edition. E. and S. Livingstone, London, United Kingdom. 1457 pp.
Other references
• Bagavathi, R., Sorg, B. & Hecker, E., 1988. Tigliane-type diterpene esters from Synadenium grantii. Planta Medica 54(6): 506–510.
• Banderembako, F. & Ntitangirageza, T., 1978. La mιdecine populaire au Burundi: quelques plantes mιdicinales. Que vous en semble 35. 20 pp.
• Beentje, H.J., 1994. Kenya trees, shrubs and lianas. National Museums of Kenya, Nairobi, Kenya. 722 pp.
• Bossard, E., 1993. Angolan medicinal plants used also as piscicides and/or soaps. Journal of Ethnopharmacology 40: 1–19.
• Chifundera, K., 2001. Contribution to the inventory of medicinal plants from the Bushi area, South Kivu Province, Democratic Republic of Congo. Fitoterapia 72: 351–368.
• El Sayed, M.M., 1993. Isolation of diterpene esters from Synadenium grantii as molluscicidal agent. Egyptian Journal of Pharmaceutical Sciences 33(5–6): 819–824.
• Govindappa, T., Govardhan, L., Jyothy, P.S. & Veerabhadrappa, P.S., 1987. Purification and characterization of acetylcholinesterase isozymes from the latex of Synadenium grantii Hook.f. Indian Journal of Biochemistry and Biophysics 24(4): 209–217.
• Kinghorn, D., 1980. A major skin-irritant principle from Synadenium grantii. Journal of Pharmaceutical Science 69(12): 1446–1447.
• Mrinalini, M., Vithayathil, P.J., Raju, S.M. & Ramadoss, C.S., 2002. Isolation and characterization of proteolytic enzymes from the latex of Synadenium grantii Hook.f'. Plant Science 163(1): 131–139.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Nielsen, P.E., Nishimura, H., Liang, Y. & Calvin, M., 1979. Steroids from Euphorbia and other latex-bearing plants. Phytochemistry 18: 103–104.
• Olivier, G.W.J., Rowan, M.G., Branch, S.K., Mahon, M.F. & Molloy, K.C., 1992. Two esters of synadenol, a new lathyrane diterpenoid from the latex of Synadenium compactum, Euphorbiaceae: a crystal structure analysis. Journal of the Chemical Society Perkin Transactions 10(14): 1831–1835.
• Okello-Onen, J., Kerwegi, S.A., Olila, D., Ssekitto, C.M.B. & Osinde, C., 2004. Participatory evaluation and improvement of ethno-veterinary practices for tick control in Lango and Teso farming system. Final Technical Report. LIRI, Tororo, Uganda. 20 pp.
• Premaratna, A., Shadaksharaswamy, M. & Nanjappa, S., 1981. Isolation, purification and properties of a lectin from the latex of Synadenium grantii. Indian Journal of Biochemistry and Biophysics 18(1): 32–35.
• Shoeb, H.A., El Sayed, M.M., El Askalany, M.A., El Nahas, H.A. & Refai, L.A., 1990. The molluscicidal properties of Synadenium grantii. Assiut Veterinary Medical Journal 23(45): 30–38.
• Tabuti, J.R.S., Lye, K.A. & Dhillion, S.S., 2003. Traditional herbal drugs of Bulamogi, Uganda: plants, use and administration. Journal of Ethnopharmacology 88: 19–44.
• Unnikrishnan, M.K., Desai, V.B. & Guruswamy, M.N., 1987. Hypothermic activity of the ethanolic extract of the latex of Synadenium grantii. Fitoterapia 58(4): 277–279.
• Uzabakiliho, B., Largeau, C. & Casadevall, E., 1987. Latex constituents of Euphorbia candelabrum, Euphorbia grantii, Euphorbia tirucalli and Synadenium grantii. Phytochemistry 26(1): 3041–3046.
• Van Puyvelde, L., Geiser, I., Rwangabo, P.-C. & Sebikali, B., 1983. Rwandese herbal remedies used against gonorrhoea. Journal of Ethnopharmacology 8: 279–286.
• van Wyk, B.E., van Heerden, F. & van Oudtshoorn, B., 2002. Poisonous plants of South Africa. Briza Publications, Pretoria, South Africa. 288 pp.
Sources of illustration
• 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.
Author(s)
• M.J. Nicholson
Plants for Life, P.O. Box 617, Limuru, Kenya


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, Rιduit, 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:
Nicholson, M.J., 2008. Euphorbia pseudograntii Bruyns. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes mιdicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
Distribution Map wild


flowering branch.
Redrawn and adapted by Achmad Satiri Nurhaman