Trichilia dregeana

Family

Meliaceae

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Chromosome number

2n = c. 360

Synonyms

Trichilia splendida A.Chev. (1911).

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Vernacular names

Forest mahogany, forest Natal mahogany, Cape mahogany, thunder tree, christmas bells, red ash (En). Aribanda des montagnes (Fr). Mafureira (Po). Mkungwina, mtimaji (Sw).

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Origin and geographic distribution

Trichilia dregeana has a disjunct natural distribution area in tropical Africa. It occurs from Ethiopia south to South Africa, especially in the mountain ranges of the Eastern Arc and along the Rift Valley. In West and Central Africa it occurs in areas far remote from each other, in Guinea, Côte d’Ivoire, Cameroon, in Congo, DR Congo and Angola. It is absent from the central Congolian rainforest, but is reported from the Arabian peninsula. It is planted in many countries as an ornamental.

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Uses

The seeds provide an oil which is used to make candles, soap and cosmetics. It is used for cooking although it is bitter. The seedcoat is poisonous and only well-prepared oil is safe for consumption. After removal of the seedcoat and boiling, the seeds are eaten as a side dish. The seed residue after oil extraction is used as animal feed or as fertilizer. Fruits are eaten in KwaZulu-Natal (South Africa). The aril is eaten, or crushed and made into a sweet drink or sauce.
Throughout Africa the seed oil, leaves, root and bark of Trichilia dregeana have similar medicinal uses to those of Trichilia emetica Vahl. They are used to treat a variety of complaints ranging from lumbago to leprosy and sleeplessness. The seed oil is rubbed into cuts made in the skin of a fractured limb in order to hasten healing; it is used as a massage oil to treat rheumatism and as a general body ointment. The fruit has emetic and purgative properties. Poultices made of the leaves or fruits are applied to bruises and eczema. Root decoctions are used as a general tonic, against fever and as a purgative. In Ethiopia the bark is used against scabies. Decoctions of the bark are applied in the form of an enema as a purgative and abortifacient, and to treat back pain caused by kidney problems. Bark decoctions are also drunk as a purgative or abortifacient. A bark decoction is drunk daily to treat diarrhoea. The bark is also used in the preparation of fish poison.
The wood is important for carving, especially in southern Africa, and is also used for indoor furniture, household utensils, shelving, construction, dugout canoes, firewood, and for making charcoal. Trichilia dregeana makes a beautiful shady avenue tree and is grown as an ornamental. A selection with small leaves and short internodes has been patented in the United States. In Ethiopia it is grown as a shade tree for coffee, or left as such when forest is cleared. The bright-coloured seeds have been used as bait for fishing.

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Production and international trade

Trichilia dregeana is of subsistence value in most parts of Africa, but the seed, roots and leaves are collected and traded locally, especially in South Africa. Seeds are harvested on a commercial scale from wild trees for the industrial production of pharmaceutical products.

Properties

The seed of Trichilia dregeana contains 55–65% oil. The approximate fatty acid composition of the oil is: palmitic acid 34%, stearic acid 3%, oleic acid 51%, linoleic acid 11%, linolenic acid 1%.
A large number of limonoids have been isolated from the seed, especially from the seedcoat. Limonoids are tetraterpenoids, many of which are biologically active. The limonoids in Trichilia dregeana are evodulone and prieurianin derivatives, including dregeanin, dregeana 1–5 and rohituka 7. Limonoids of the Meliaceae are well known as antifeedants and growth regulators of insects, but they also have some antimicrobial and anti-inflammatory activities and have shown cell-adhesion inhibitory properties. The bark, which is very toxic, contains inhibitors of the prostaglandin-synthesis, which play a role in inflammation and pain suppression.
The heartwood of Trichilia dregeana is pale brown to pink, the sapwood whitish. The wood darkens with age. When oiled, it darkens considerably, leaving little difference between heartwood and sapwood. The grain is generally straight, texture medium coarse. The wood has a distinct figure. The density at 12% moisture is about 550 kg/m³. Drying is fast and easy with little defect. The wood is easily worked and polishes well. It is not durable and susceptible to borer attack.

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Adulterations and substitutes

In most regions of Africa, Trichilia emetica is preferred to Trichilia dregeana for its oil and for medicinal purposes.

Description

Evergreen, dioecious, medium-sized tree up to 30(–40) m tall, variously hairy in all parts; bole cylindrical, up to 100(–200) cm in diameter, often slightly buttressed; bark 3–4 cm thick, outer bark pale grey to grey-brown, smooth, inner bark soft, cream-coloured, quickly turning pink to reddish brown; crown dense, spreading. Leaves alternate, imparipinnately compound with 2–5 pairs of leaflets; stipules absent; petiole and rachis up to 26 cm long; petiolules up to 1 cm long; leaflets opposite, obovate to oblanceolate, up to 21 cm × 8.5 cm, base rounded or cuneate, apex nearly always acute or acuminate, rarely rounded or notched, entire, pinnately veined with 8–14 pairs of lateral veins. Inflorescence an axillary or terminal panicle up to 11(–24) cm long, usually few-flowered. Flowers unisexual, male and female flowers very similar in appearance, regular, 5-merous, dirty white; pedicel up to 4(–10) mm long; calyx cup-shaped, 3.5–5.5(–7.5) mm × 5.5–9(–11) mm, usually lobed to halfway or more, lobes broadly ovate, 1–3 mm × 2–4 mm, hairy; petals free, linear, 13–22 mm long, hairy; stamens 10, 10–16 mm long, united into a tube in basal half, densely hairy inside; ovary superior, densely hairy, 3-celled, style 6–8.5 mm long, stigma head-shaped or disk-shaped; male flowers with rudimentary ovary, female flowers with non-dehiscing anthers. Fruit an obovoid to globose capsule c. 3 cm × 3 cm, slightly 3-lobed, without distinct stipe, dehiscent, up to 6-seeded. Seeds 18–25 mm × 9–15 mm, glossy black, almost completely concealed in a scarlet sarcotesta. Seedling with epigeal germination; hypocotyl up to 4 cm long, epicotyl 4–8 cm long; cotyledons sessile, fleshy; first leaves opposite and simple, subsequent leaves alternate and simple, becoming compound from c. 8^th leaf.

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Other botanical information

Trichilia comprises about 90 species, most of them in tropical America. In continental Africa 18 species occur, and 6 in Madagascar. Trichilia dregeana is closely related and very similar to Trichilia emetica. The two species are often confused. The latter occurs in drier locations and can be distinguished by a distinct stipe on the fruit. Trichilia emetica occurs in riparian woodland or similar vegetation in drier areas from sea-level up to 1500 m altitude. Although Trichilia dregeana is very variable and its distribution area disrupted, morphological variation patterns in East Africa and West Africa are similar and no subspecific taxa have been recognized.

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Growth and development

Natural reproduction of Trichilia dregeana is abundant owing to regular and copious seeding from a fairly early age, comparative immunity from damage by animals and its power of recovery from injury. Seeds germinate during the early rains and seedlings attain a length of 10–20 cm by the end of the first year. In subsequent years, growth is more rapid, the mean annual girth increment being 2–2.5 cm. In Zimbabwe trees flower in September–December and fruit fall starts in May. Trees growing in the open start fruiting when about 10 years old, those in more shaded, forest-like conditions may not bear fruit before they are 20 years old.

Ecology

In West Africa Trichilia dregeana is found in the transition zone between forest-savanna mosaic and moist evergreen forest, mostly at 800–1600 m altitude. In western DR Congo it occurs in similar vegetation, but below 500 m altitude. The distribution in Ethiopia is at 1350–2000 m altitude where annual rainfall is 1500–2500 mm, while nearer the equator in Uganda and Tanzania its distribution starts at lower altitudes. Towards South Africa it occurs at gradually lower altitudes and is found at sea-level near Durban. Though sensitive to frost, the tree recovers easily from damage. It is tolerant of fire. It is mostly found in well-watered sites, on fertile forest soil. In gardens it can be grown both in shady places and in full sunlight.

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Propagation and planting

Trichilia dregeana is easily propagated by seed, either by direct sowing or by raising seedlings in a nursery. The weight of 1000 seeds is about 1 kg. The seed must be fresh when sown as viability is lost very quickly on drying. It germinates within 2–4 weeks; removal of the fleshy outer seedcoat promotes germination. A rich mixture of sandy soil and compost with plenty of moisture is recommended. Seedlings grow best under some shade and should be protected from frost.

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Management

Trichilia dregeana is only cultivated on a small scale, mainly as a garden plant. Older plants are fast growing and require little or no management. For ornamental purposes trees may be pruned into shrubs. Trichilia dregeana coppices well.

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Harvesting

Seeds are generally collected from wild stands.

Yield

Average seed yields per tree in Mozambique are about 20–25 kg/year, but in a good year a large tree may produce 180 kg. Trees that have produced heavily in one year tend to produce little in the next year.

Handling after harvest

To obtain the oil, the seeds are ground and pounded. The mashed seeds are boiled in water and the oil is skimmed off.

Genetic resources and breeding

Trichilia dregeana is widely distributed in tropical Africa and is characterized by regular and copious seeding and therefore not endangered.

Prospects

The oil of Trichilia dregeana is gradually being replaced by other, commercially available oils, but as an ornamental amenity tree it seems to be becoming increasingly popular. Seeds might be usable as starting material for the partial synthesis of limonoids of pharmaceutical interest, so deserve further attention. Seed of Trichilia dregeana is recalcitrant; procedures for storing embryos are being developed, but have only shown short-term success. Research is likely to continue.

Major references

• CHCD, 1996. Dictionary of natural products on CD-ROM, release 4.2. Chapman & Hall, London, United Kingdom.
• de Wilde, J.J.F.E., 1986. A revision of the species of Trichilia P. Browne (Meliaceae) on the African continent. Mededelingen van de Landbouwhogeschool Wageningen 68–2. Wageningen, Netherlands. 207 pp.
• 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.
• Grace, O.M., Prendergast, H.D.V., Jäger, A.K. & van Staden, J., 2002. Bark medicines in traditional healthcare in KwaZulu-Natal, South Africa: an inventory. South African Journal of Botany 69(3): 301–363.
• Grundy, I.M. & Campbell, B.M., 1993. Potential production and utilisation of oil from Trichilia spp. (Meliaceae). Economic Botany 47(2): 148–153.
• Katende, A.B., Birnie, A. & Tengnäs, B., 1995. Useful trees and shrubs for Uganda: identification, propagation and management for agricultural and pastoral communities. Technical Handbook 10. Regional Soil Conservation Unit, Nairobi, Kenya. 710 pp.
• Mulholland, D.A., Parel, B. & Coombes, P.H., 2000. The chemistry of the Meliaceae and Ptaeroxylaceae of Southern and Eastern Africa and Madagascar. Current Organic Chemistry 4(10): 1011–1054.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Palmer, E. & Pitman, N., 1972–1974. Trees of southern Africa, covering all known indigenous species in the Republic of South Africa, South-West Africa, Botswana, Lesotho and Swaziland. 3 volumes. Balkema, Cape Town, South Africa. 2235 pp.
• White, F. & Styles, B.T., 1963. Meliaceae. In: Exell, A.W., Fernandes, A. & Wild, H. (Editors). Flora Zambesiaca. Volume 2, part 1. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. pp. 285–319.

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Other references

• Beentje, H.J., 1994. Kenya trees, shrubs and lianas. National Museums of Kenya, Nairobi, Kenya. 722 pp.
• Berjak, P., Kioko, J.I., Makhathini, A. & Watt, M.P., 2004. Strategies for field collection of recalcitrant seeds and zygotic embryonic axes of the tropical tree, Trichilia dregeana Sond. Seed Science and Technology 32(3): 825–836.
• Berjak, P. & Mycock, D., 2004. Calcium, with magnesium, is essential for normal seedling development from partially dehydrated recalcitrant axes: a study on Trichilia dregeana Sond. Seed Science Research 14: 217–231.
• Burkill, H.M., 1997. The useful plants of West Tropical Africa. 2nd Edition. Volume 4, Families M–R. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 969 pp.
• Burring, J.-H., 2006. Trichilia dregeana. [Internet] South African National Biodiversity Institute, Belville, South Africa. http://www.plantzafrica.com/ planttuv/ trichildreg.htm. Accessed September 2006.
• Choinski, J.S. jr., 1990. Aspects of viability and post-germinative growth in seeds of the tropical tree, Trichilia dregeana Sonder. Annals of Botany 66: 437–442.
• Coates Palgrave, K., 1983. Trees of southern Africa. 2nd Edition. Struik Publishers, Cape Town, South Africa. 959 pp.
• Mulholland, D.A. & Taylor, D.A.H., 1980. Limonoids from the seed of the Natal Mahogany, Trichilia dregeana. Phytochemistry 19: 2421–2425.
• Pennington, T.D. & Styles, B.T., 1975. A generic monograph of the Meliaceae. Blumea 22: 419–540.
• Ruffo, C.K., Birnie, A. & Tengnäs, B., 2002. Edible wild plants of Tanzania. Technical Handbook No 27. Regional Land Management Unit/ SIDA, Nairobi, Kenya. 766 pp.
• Song, S.-Q., Berjak, P. & Pammenter, N., 2004. Dessiccation sensitivity of Trichilia dregeana axes and antioxidant role of ascorbic acid. Acta Botanica Sinica 46(7): 803–810.
• Styles, B.T. & Vosa, C.G., 1971. Chromosome numbers in the Meliaceae. Taxon 20(4): 485–500.
• Styles, B.T. & White, F., 1991. Meliaceae. In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 68 pp.
• 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.
• Wild, H., Biegel, H.M. & Mavi, S., 1972. A Rhodesian botanical dictionary of African and English names. 2nd Edition. Government Printer, Salisbury, Rhodesia.

Afriref references

Sources of illustration

• de Wilde, J.J.F.E., 1986. A revision of the species of Trichilia P. Browne (Meliaceae) on the African continent. Mededelingen van de Landbouwhogeschool Wageningen 68–2. Wageningen, Netherlands. 207 pp.

Author(s)

•	A. Maroyi Department of Biological Sciences, Bindura University of Science Education, P.B. 1020, Bindura, Zimbabwe

Editors

•	H.A.M. van der Vossen Steenuil 18, 1606 CA Venhuizen, Netherlands
•	G.S. Mkamilo Naliendele Agricultural Research Institute, P.O. Box 509, Mtwara, Tanzania

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

Photo editor

•	A. de Ruijter PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article

Maroyi, A., 2007. Trichilia dregeana Sond. [Internet] Record from PROTA4U. van der Vossen, H.A.M. & Mkamilo, G.S. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. <http://www.prota4u.org/search.asp>. Accessed .

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