Combretum erythrophyllum (PROTA)

Plant Resources of Tropical Africa Introduction

List of species

Combretum erythrophyllum (Burch.) Sond.

1, flowering twig; 2, inflorescence; 3, fruit. Redrawn and adapted by Iskak Syamsudin

Protologue: Linnaea 23:43 (1850).

Family: Combretaceae

Chromosome number: 26

Vernacular names

• River bush-willow, bush-willow, river combretum (En).

Origin and geographic distribution

Combretum erythrophyllum occurs in southern Africa and South Africa.

Uses

Throughout southern Africa root bark and stem bark decoctions are taken as a strong purgative and to treat cough, infertility, leprosy and venereal diseases. They are also taken as an anti-abortifacient and aphrodisiac. A leaf infusion is taken to treat abdominal pain. In Zimbabwe root powder is inserted into the vaginal canal to contract it during intercourse. It is a dangerous practice and fatalities have been reported. The Zulu give small doses of the root to their dogs as a fattening tonic. Dried and powdered gum is applied to sores. The fruit is poisonous, producing persistent hiccup; it is sometimes chewed as an anthelmintic.

The bark gum is non-toxic, elastic, and produces a non-cracking varnish. The gum was once used in tanneries as a substitute for gum from Astragalus spp. A dark, rich brown dye is extracted from the roots which is used for tanning hides. The wood is yellow, tough and easily worked, but not durable. It is used for making cattle troughs and grain mortars, household utensils and ornaments. It is also widely used as firewood.

Combretum erythrophyllum is planted as an ornamental and shade tree. Dried fruits are used for decoration purposes.

Production and international trade

In South Africa and the United States Combretum erythrophyllum is sold as an ornamental tree.

Properties

Leaf extracts yielded 7 flavonoids with antibacterial properties: apigenin, kaempferol, rhamnocitrin, rhamnazin, quercetin-5,3’-dimethylether, genkwanin and 5-hydroxy-4’,7-dimethoxyflavone. Seven cycloartane triterpenes have been isolated from the leaves, with erythrophyllic acid being the representative compound. Several stilbenoids were isolated from the wood: combretastatin A-1, (-)-combretastatin, combretastatin A-1 2’-β-D-glucoside and combretastatin B-1 2’-β-D-glucoside.

A methanol extract of the wood showed inhibitory bioactivities in a yeast-based assay for DNA-damaging agents. An acetone extract of the leaves showed highly significant growth inhibition of Staphylococcus aureus. A leafy twig extract showed mutagenic activity against Salmonella typhimurium strains TA100 and TA102.

The stilbenes exhibited cytotoxic effects against cancer cell lines and inhibited the growth of a DNA-repair deficient strain of Saccharomyces cerevisiae. All flavonoids showed good activity against Vibrio cholerae and Enterococcus faecalis, with MIC values in the range of 25–50 μg/ml. Rhamnocitrin and quercetin-5,3’-dimethylether also inhibited Micrococcus luteus and Shigella sonei at 25 μg/ml. With the exception of 5-hydroxy-7,4’-dimethoxy-flavone the flavonoids were not toxic towards human lymphocytes. This compound was potentially toxic to human cells and exhibited the poorest antioxidant activity. Combretastatin A-1 phosphate has been evaluated as a prodrug causing rapid vascular shutdown within tumors. Combretastatin A-1 phosphate is more potent against a well-vascularised murine colon tumour than its predecessor, combretastatin A-4 phosphate, and may have potential for clinical development. Rhamnocitrin and rhamnazin exhibited strong antioxidant activity.

High anti-inflammatory activity was found in vitro in an ethyl acetate extract of the leaves. Genkwanin, rhamnocitrin, quercetin-5,3’-dimethylether and rhamnazin had a higher anti-inflammatory activity than the positive control mefenamic acid. A stem bark extract showed highly significant antiplasmodial activity with IC50 value of 1 μg/ml against a chloroquine-resistant Plasmodium falciparum strain. Different leaf extracts did not show any anthelmintic or antischistosomal activity in vitro. Ethanolic stem bark extracts exhibited inhibitory activity again prostaglandin-synthesis and showed relaxation of pre-contracted guinea pig uterus.

The wood has coarse and rather featureless grains. There is no real distinction between sapwood and heartwood. The wood is yellow, tough and moderately heavy (air-dry: 670 kg/m³).

Adulterations and substitutes

The gum of Combretum erythrophyllum is sometimes used as adulterant of gum arabic from Acacia senegal (L.) Willd.

Description

Small to large spreading, deciduous tree up to 10 m tall, often with multiple stems; young branches densely short-hairy, pinkish after shedding the bark; bark pale brown, smooth, flaking with age to expose grey patches; knob-like outgrowths commonly occur in older trees. Leaves almost opposite or sometimes in whorls of 3; stipules absent; petiole 1–4 mm long, short-hairy; blade elliptical, up to 5 cm × 2 cm, apex acute and mucronate, base cuneate, both surfaces with inconspicuous scales, nearly glabrous above, except on midrib and veins, densely hairy to nearly glabrous beneath, pinnately veined with 6–8(–12) pairs of lateral veins; blade pale yellow when young. Inflorescence a dense, rounded axillary spike up to 2(–3) cm long, rarely forming short, dense panicles by the suppression of leaves on short shoots; rachis and peduncles usually densely short-hairy. Flowers bisexual, regular, 4-merous, cream or yellow; receptacle consisting of 2 parts, lower part 1.5–2.5 mm long, densely short-hairy, upper part broadly campanulate, 2–2·5 mm long, short-hairy, with some scales visible; sepals c. 1 mm × 1.5 mm, petals obovate, narrowly obovate, spoon-shaped or narrowly elliptical, c. 1.5 mm × 1 mm, glabrous; stamens 8, c. 5 mm long; ovary inferior, 1-celled. Fruit a 4-winged nut, c. 1.3 cm × 1 cm, almost circular or broadly elliptical to elliptical in outline, scaly and short-hairy, with 6–7 mm long stipe and c. 5 mm wide wings, greenish brown, ripening to yellowish brown and drying to a honey-brown, indehiscent, 1-seeded, remaining on the tree for a long time. Seedling with hypogeal germination.

Other botanical information

Combretum is a very large genus, comprising about 250 species and distributed worldwide in the tropics and subtropics. About 140 species occur in tropical Africa; c. 20 species are endemic to Madagascar.

Combretum erythrophyllum is very similar to Combretum caffrum (Eckl. & Zeyh.) Kuntze, ‘Cape bush-willow’, which only occurs in eastern South Africa, and which prefers a similar habitat.

Growth and development

Combretum erythrophyllum is fast growing under good conditions, up to 4 m in three years. In southern Africa Combretum erythrophyllum flowers in September–November and fruits in January–October. The tree produces beautiful autumn colours before the leaves drop, especially in regions with frost.

Ecology

Combretum erythrophyllum occurs in dry woodland and savanna, especially on river banks, occasionally on copper bearing soils, from sea-level up to 1500 m altitude. It can tolerate a variety of soils, including heavy black loam, sandy riverine alluvium and granite sand. It is rather drought and frost tolerant.

Propagation and planting

Combretum erythrophyllum is propagated by seed. Average seed weight is 42.7 g/1000 seeds. Removal of the fruit coat and scarification with hot water improved germination rate and uniformity of germination. Hot water treatment improved germination rate of both the seeds and the fruits, better than stratification and soaking in water. Fresh seeds are sown in seedling trays filled with a mixture of river sand and humus-rich soil; the seeds are covered with a thin layer of sand. Seeds germinate within 7–16 days, with a germination rate of 70–90%. Seedlings are transplanted into black nursery bags at the 2-leaf stage and at 30–50 cm they can be transplanted into the field. They grow best in deep, well-drained soil with ample water, and they must be protected from frost for the first 2–3 winters.

Combretum erythrophyllum sets lots of seed and seedlings are often to be found under the trees. About 15% of the seeds is parasitized.

Diseases and pests

Wasps lay eggs in the seeds, which are eaten by newly hatched larvae. Combretum erythrophyllum may be subject to die-back of small stems due to stalk-boring insects. Older trees are often attacked by trunk rot (Polyporus spp.).

Genetic resources

Combretum erythrophyllum is widespread in it distribution area, regenerates well and is therefore not in danger of genetic erosion.

Prospects

Combretum erythrophyllum shows interesting antimicrobial, antiplasmodial and anti-inflammatory activities, and also contains the promising anti-tumor compound combretastatin A-1 phosphate. Further research to establish the safety profiles of its extracts and compounds is warranted. It also has potential as an ornamental plant.

Major references

• Eloff, J.N., 1999. The antibacterial activity of 27 southern African members of the Combretaceae. South African Journal of Science 95: 148–152.
• Le Roux, L.-N., 2003. Combretum erythrophyllum. [Internet] South African National Biodiversity Institute, Cape Town, South Africa. http://www.plantzafrica.com/plantcd/combreteryth.htm Accessed April 2011.
• Lindsey, K., Jäger, A.K., Raidoo, D.M. & van Staden, J., 1999. Screening of plants used by southern African traditional healers in the treatment of dysmenorrhoea for prostaglandin-synthesis inhibitors and uterine relaxing activity. Journal of Ethnopharmacology 64: 9–14.
• Martini, N.D., Katerere, D.R.P. & Eloff, J.N., 2004. Biological activity of five antibacterial flavonoids from Combretum erythrophyllum (Combretaceae). Journal of Ethnopharmacology 93(2–3): 207–212.
• Martini, N.D., Katerere, D.R.P. & Eloff, J.N., 2004. Seven flavonoids with antibacterial activity isolated from Combretum erythrophyllum. South African Journal of Botany 70(2): 310–312.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Rogers, C.B., 1998. Cycloartenoid dienone acids and lactones from Combretum erythrophyllum. Phytochemistry 49(7): 2069–2076.
• Schwikkard, S., Zhou, B.N., Glass, T.E., Sharp, J.L., Mattern, M.R., Johnson, R.K. & Kingston, D.G., 2000. Bioactive compounds from Combretum erythrophyllum. Journal of Natural Products 63(4): 457–460.
• van Dyk, S., Griffiths, S., van Zyl, R.L. & Malan, S.F., 2009. The importance of including toxicity assays when screening plant extracts for antimalarial activity. African Journal of Biotechnology 8(20): 5595–5601.
• Wickens, P. & Gaum, W.G., 2001. Scarification and stratification of Combretum erytrophyllum (burchell) seed and fruit for uniformity in germination. South African Journal of Plant and Soil 18(4): 171–173.

Other references

• Coates Palgrave, K., 2002. Trees of southern Africa. 3rd Edition. Struik Publishers, Cape Town, South Africa. 1212 pp.
• Eloff, J.N., 1999. It is possible to use herbarium specimens to screen for antibacterial components in some plants. Journal of Ethnopharmacology 67(3): 355–360.
• Exell, A.W., 1978. Combretaceae. In: Launert, E. (Editor). Flora Zambesiaca. Volume 4. Flora Zambesiaca Managing Committee, London, United Kingdom. pp. 100–183.
• Gelfand, M., Mavi, S., Drummond, R.B. & Ndemera, B., 1985. The traditional medical practitioner in Zimbabwe: his principles of practice and pharmacopoeia. Mambo Press, Gweru, Zimbabwe. 411 pp.
• Holwell, S.E., Cooper, P., Grosios, K., Lippert, J.W., Pettit, G.R., Shnyder, S.D. & Bibby, M.C., 2002. Combretastatin A-1 phosphate, a novel tubulin-binding agent with in vivo anti vascular effects in experimental tumours. Anticancer Research 22(2a): 707–712.
• Kirwan, I.G., Loadman, P.M., Swaine, D.J., Anthoney, D.A., Pettit, G.R., Lippert III, J.W., Shnyder, S.D., Cooper, P.A. & Bibby, M.C., 2004. Comparative preclinical pharmacokinetic and metabolic studies of the combretastatin prodrugs combretastatin A4 phosphate and A1 phosphate. Clinical Cancer Research 10: 1446–1453.
• Martini, N. & Eloff, J.N., 1998. The preliminary isolation of several antibacterial compounds from Combretum erytrophyllum (Combretaceae). Journal of Ethnopharmacology 62(3): 255–263.
• McGaw, L.J., Rabe, T., Sparg, S.G., Jäger, A.K., Eloff, J.N. & van Staden, J., 2001. An investigation on the biological activity of Combretum species. Journal of Ethnopharmacology 75: 45–50.
• SEPASAL, 2011. Combretum erythrophyllum. [Internet] Survey of Economic Plants for Arid and Semi-Arid Lands (SEPASAL) database. Royal Botanic Gardens, Kew, Richmond, United Kingdom. http://www.kew.org/ ceb/sepasal/. Accessed March 2011.
• Sohni, Y.R., Mutangadura, M.T. & Kale, P.G., 1994. Bacterial mutagenicity of eight medicinal herbs from Zimbabwe. Mutation Research 322(2): 133–140.
• Sohni, Y.R. & Kale, P.G., 1997. Mutagenicity of Combretum erythrophyllum in sex-linked recessive lethal test in Drosophila. Phytotherapy Research 7: 524–526.
• Steenkamp, V., 2003. Traditional herbal remedies used by South African women for gynaecological complaints. Journal of Ethnopharmacology 86: 97–108.
• Stoffberg, G.H., van Rooyen, M.W., van der Linde, M.J. & Groeneveld, H.T., 2008. Predicting the growth in tree height and crown size of three street tree species in the City of Tshwane, South Africa. Urban Forestry and Urban Greening 7(4): 259–264.
• Tempelhoff, J., 1991. The exploitation of timber resources in northern Transvaal, South Africa, in the 19th century and early conservation measures. South African Forestry Journal 158: 67–74.
• Tietema, T., Ditlhogo, M., Tibone, C. & Mathalaza, N., 1991. Characteristics of eight firewood species of Botswana. Biomass and Bioenergy 1(1): 41–46.
• van Wyk, B.E. & Gericke, N., 2000. People’s plants: a guide to useful plants of southern Africa. Briza Publications, Pretoria, South Africa. 351 pp.
• van Wyk, B.E., van Oudtshoorn, B. & Gericke, N., 1997. Medicinal plants of South Africa. Briza Publications, Pretoria, South Africa. 304 pp.
• 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.

Sources of illustration

• Engler, A., 1899. Monographien Afrikanischer Pflanzen-Familien und - Gattungen. 3. Combretaceae - Combretum. Wilhelm Engelmann, Leipzig, Germany. 116 pp. + 30 tables.

Author(s)

• D.E. Tsala, Department of Life and Earth Sciences, Higher Teachers’ Training College, University of Maroua I, P.O. Box 55, Maroua, Cameroon

Correct citation of this article

Tsala, D.E. & Nga, Nganga, 2012. Combretum erythrophyllum (Burch.) Sond. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(2): Medicinal plants/Plantes médicinales 2. PROTA, Wageningen, Netherlands. Accessed 23 December 2024.

• See this page on the Prota4U database.