Duguetia staudtii (PROTA)

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Duguetia staudtii (Engl. & Diels) Chatrou


distribution in Africa (wild)
1, base of bole; 2, flowering twig; 3, fruit; 4, seed. Redrawn and adapted by J.M. de Vries
leaves
leaves
flower
fruits
wood in transverse section
wood in tangential section
wood in radial section
Protologue: Changing Gen.: 70 (1998).
Family: Annonaceae

Synonyms

  • Pachypodanthium staudtii (Engl. & Diels) Engl. & Diels (1900).

Origin and geographic distribution

Duguetia staudtii occurs from Sierra Leone east to the Central African Republic and south to Gabon and DR Congo.

Uses

The wood of Duguetia staudtii, known as ‘ntom’ in Central Africa and as ‘aniouketi’ in Côte d’Ivoire, is locally used, especially in house construction for poles and planks, but also for carpentry and utensils; it is suitable for flooring, joinery, interior trim, mine props, furniture, cabinet making, toys, novelties, boxes, crates, vats, food containers, turnery, veneer and plywood.

The bark is used in hut construction for walls, partitions and doors. It is commonly used in traditional medicine. Bark decoctions are taken to treat colds, cough and other complaints of the respiratory tracts, and as anodyne, purgative, anthelmintic and aphrodisiac. They are used as mouth wash against toothache, and to wash the hair to get rid of lice. A paste of pounded bark is applied externally to treat smallpox and measles. The bark is also used to treat tumours, oedema, leprosy and gonorrhoea. Pulped bark with cola nut is taken against gastro-intestinal problems. Leaf decoctions are applied in mixtures to wash the body to treat measles. In Côte d’Ivoire stem bark is used as an ingredient in the preparation of arrow poison.

Production and international trade

The wood of Duguetia staudtii is only used locally and not or rarely traded on the international market.

Properties

The heartwood is pale yellow to yellowish brown or greenish brown, indistinctly demarcated from the slightly paler, up to 8 cm wide sapwood. The wood is susceptible to discolouration to a greyish tinge. The grain is straight, texture moderately coarse.

The wood is medium-weight to fairly heavy, with a density of 670–830 kg/m³ at 12% moisture content, moderately hard and tough. It air dries well without serious degrade, except occasional end checking. The rates of shrinkage are rather high, from green to oven dry 3.4–5.9% radial and 8.2–10.6% tangential. In Liberia boards of 2.5 cm thick could be air dried from green to 20% moisture content in 6 weeks. No defects were observed in kiln drying the wood from 60% to 20% moisture content in 72 hours.

At 12% moisture content, the modulus of rupture is 139–168 N/mm², modulus of elasticity 8530–19,600 N/mm², compression parallel to grain 59–88 N/mm², shear 8 N/mm², cleavage 16–18 N/mm, Janka side hardness 9050 N and Chalais-Meudon side hardness 4.0–4.2.

The wood works easily with both hand and machine tools, and has little dulling effect on cutting edges. It can be planed to an attractive lustrous surface, and finishes smoothly. The nailing and screwing properties are satisfactorily, and the wood glues well. It takes paints and vanish well. The peeling and slicing characteristics are good. The wood is not durable, being susceptible to attacks by fungi and termites, although it has also been reported to be quite resistant to termite attack; the sapwood is liable to Lyctus attack. The wood is moderately easy to treat with preservatives.

The wood contains about 42% cellulose, 29.5% lignin, 16% pentosan, 1.7% ash and less than 0.02% silica. The solubility is 1.2% in alcohol-benzene, 3.4% in hot water and 17.1% in a 1% NaOH solution.

The bark and leaves contain alkaloids, mainly isoquinoline alkaloids, and the presence of tannins has been reported in the bark and roots. Some bisnorlignans have been isolated from the bark, as well as the flavonol pachypodol, which has potent antiviral activity against poliovirus. Crude bark extracts killed microfilariae and adult females of Onchocerca volvulus, the causal organism of river blindness; oliverine was identified as active compound. 2,4,5-Trimethoxystyrene has been isolated in larger amounts from the bark. This compound is toxic to brine shrimp, but showed only weak cytotoxic activity. It showed significant insecticidal activity against Callosobruchus maculatus, a pest in stored cowpea, and Sitophilus zeamais, a pest of stored maize. The essential oil from the bark contained more than 70% of 2,4,5-trimethoxystyrene, and the oil showed in-vitro activity against Plasmodium falciparum. Ethanol bark extracts showed high toxicity in tests with rats. Bark extracts showed antifungal activity against Candida albicans and Cladosporium cucumerinum.

Description

  • Evergreen, medium-sized to fairly large tree up to 35(–50) m tall; bole branchless for up to 20 m, straight and cylindrical, up to 70(–90) cm in diameter, without buttresses but sometimes slightly swollen at base; bark surface smooth to slightly rough, shallowly longitudinally fissured, yellowish to greenish grey, inner bark thick, fibrous, with thick granular to gritty stripes, yellow to orange-brown, turning darker upon exposure, strongly scented; crown small, with horizontal branches; twigs drooping, slightly hairy, becoming glabrous.
  • Leaves alternate, simple; stipules absent; petiole up to 1 cm long, flattened above; blade narrowly elliptical to narrowly obovate, 13–34 cm × 3–8 cm, cuneate to rounded at base, sometimes slightly cordate, acute to short-acuminate at apex, margins wavy, leathery, sparsely appressed stellate hairy below, pinnately veined with 10–22 pairs of lateral veins.
  • Inflorescence an axillary fascicle on a short peduncle up to 4(–6) mm long, 2–4-flowered, densely stellate hairy; bracts up to 12 mm long.
  • Flowers bisexual, regular, 3-merous; pedicel up to 12 mm long, elongating in fruit; sepals free, ovate, 1–1.5 cm long, densely stellate hairy outside; petals free, in 2 whorls, 0.5–2.5 cm long, creamy white, nearly glabrous; stamens numerous, arranged spirally, 1–1.5 mm long, anthers nearly sessile; carpels free, numerous, arranged spirally, ovaries 1–1.5 mm long, hairy, stigmas sessile, up to 1 mm long.
  • Fruit globose to depressed ovoid, 2–7 cm in diameter, pinkish to reddish when ripe, consisting of numerous pyramidal fruiting carpels fused at base; each fruiting carpel with woody wall, fleshy reddish pulp and 1 seed.
  • Seeds obovoid, 1–1.5 cm long, glossy brown, with up to 4 mm long, whitish aril at base.
  • Seedling with epigeal germination; hypocotyl 5–7 cm long, epicotyl very short, 1–2 mm long; cotyledons leafy, sessile, rounded, up to 2 cm in diameter, soon caducous; first 2 leaves nearly opposite.

Other botanical information

Duguetia comprises about 90 species, with the majority in tropical America and 4 species in West and Central Africa. The African species have been considered to belong to a separate genus Pachypodanthium, but the results of a cladistic analysis based on morphological and anatomical data published in 1998 led to inclusion in Duguetia.

Duguetia confinis

Duguetia confinis (Engl. & Diels) Chatrou (synonym: Pachypodanthium confine Engl. & Diels) is a medium-sized to fairly large tree up to 35(–40) m tall with bole up to 85 cm in diameter, occurring in Cameroon, Equatorial Guinea, Gabon and Congo. It differs from Duguetia staudtii in its densely hairy lower leaf surface with erect stellate hairs and in its ellipsoid fruits consisting of nearly entirely fused carpels. Its wood, with a density of about 710 kg/m³ at 12% moisture content, is similar to that of Duguetia staudtii and used for similar purposes, especially in house construction.

Anatomy

Wood-anatomical description (IAWA hardwood codes):

  • Growth rings: 1: growth ring boundaries distinct.
  • Vessels: 5: wood diffuse-porous; 13: simple perforation plates; 22: intervessel pits alternate; 23: shape of alternate pits polygonal; (24: intervessel pits minute ( 4 μm)); 25: intervessel pits small (4–7 μm); 30: vessel-ray pits with distinct borders; similar to intervessel pits in size and shape throughout the ray cell; 42: mean tangential diameter of vessel lumina 100–200 μm; 46: 5 vessels per square millimetre; (58: gums and other deposits in heartwood vessels).
  • Tracheids and fibres: 61: fibres with simple to minutely bordered pits; 66: non-septate fibres present; 69: fibres thin- to thick-walled; 70: fibres very thick-walled.
  • Axial parenchyma: 86: axial parenchyma in narrow bands or lines up to three cells wide; 88: axial parenchyma scalariform; 92: four (3–4) cells per parenchyma strand; 93: eight (5–8) cells per parenchyma strand.
  • Rays: 98: larger rays commonly 4- to 10-seriate; 102: ray height > 1 mm; (103: rays of two distinct sizes); 104: all ray cells procumbent; 106: body ray cells procumbent with one row of upright and/or square marginal cells; 115: 4–12 rays per mm.
  • Secretory elements and cambial variants: (124: oil and/or mucilage cells associated with ray parenchyma).
(C. Essien, P.E. Gasson & E.A. Wheeler)

Growth and development

In West Africa flowering is most common from February to May and fruits usually appear in July–September, but flowers and especially fruits can be found nearly throughout the year. Ripe fruits fall apart in separate carpels and are eaten by monkeys and birds, which may serve as seed dispersers.

Ecology

Duguetia staudtii usually occurs rather scattered in closed evergreen and dense riparian forest, up to 900 m altitude. It can be found in primary as well as secondary forest. It prefers sandy localities. In Gabon it has been reported to form occasionally nearly pure stands in seasonally flooded sites.

Propagation and planting

There are about 4500 seeds per kg. Seeds start germinating 2–4 weeks after sowing. The germination rate is generally high. Natural regeneration of Duguetia staudtii occurs in not too dense shade; the species is considered to be a non-pioneer light demander.

Management

In general, Duguetia staudtii occurs scattered in the forest, or in small groups. In Liberia the average wood volume of trees with a bole diameter of more than 50 cm has been estimated at 0.3 m³/ha. In forest in Cameroon, the average number of trees with a bole diameter of more than 15 cm is 0.3 per ha with a mean wood volume of 0.5 m³/ha. In Gabon the mean wood volume has been estimated at 0.6 m³/ha.

Handling after harvest

Logs should be removed rapidly from the forest after felling because they are susceptible to attacks by fungi and insects, and the wood is liable to discolouration.

Genetic resources

Duguetia staudtii is fairly widespread and there are no indications of over-exploitation, and therefore it does not seem to be threatened by genetic erosion.

Prospects

Duguetia staudtii provides a good-quality timber that can be used for various purposes, and that could be interesting for the international market. Its usually straight and cylindrical bole may offer good possibilities for veneer production by peeling. However, more information is needed on its natural regeneration and growth rates to ensure sustainable exploitation. Further research with regards to potential drug development is warranted because several of the uses of the bark in traditional medicine have been supported by pharmacological screening.

Major references

  • Bolza, E. & Keating, W.G., 1972. African timbers: the properties, uses and characteristics of 700 species. Division of Building Research, CSIRO, Melbourne, Australia. 710 pp.
  • Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families A–D. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 960 pp.
  • Chatrou, L.W., 1998. Changing genera. Systematic studies in Neotropical and West African Annonaceae. PhD thesis, Herbarium Division, Utrecht University, Utrecht, Netherlands. 224 pp.
  • Dudek, S., Förster, B. & Klissenbauer, K., 1981. Lesser known Liberian timber species. Description of physical and mechanical properties, natural durability, treatability, workability and suggested uses. GTZ, Eschborn, Germany. 168 pp.
  • Neuwinger, H.D., 1998. Afrikanische Arzneipflanzen und Jagdgifte. Chemie, Pharmakologie, Toxikologie. 2nd Edition. Wissenschaftliche Verlagsgesellschaft mbH, Stuttgart, Germany. 960 pp.
  • Oteng-Amoako, A.A. (Editor), 2006. 100 tropical African timber trees from Ghana: tree description and wood identification with notes on distribution, ecology, silviculture, ethnobotany and wood uses. 304 pp.
  • Takahashi, A., 1978. Compilation of data on the mechanical properties of foreign woods (part 3) Africa. Shimane University, Matsue, Japan. 248 pp.
  • Titanji, V.P., Evehe, M.S., Ayafor, J.F. & Kimbu, S.F., 1990. Novel Onchocerca volvulus filaricides from Carapa procera, Polyalthia suaveolens and Pachypodanthium staudtii. Acta Leidensia 59: 377–382.
  • Vivien, J. & Faure, J.J., 1985. Arbres des forêts denses d’Afrique Centrale. Agence de Coopération Culturelle et Technique, Paris, France. 565 pp.
  • Voorhoeve, A.G., 1979. Liberian high forest trees. A systematic botanical study of the 75 most important or frequent high forest trees, with reference to numerous related species. Agricultural Research Reports 652, 2nd Impression. Centre for Agricultural Publishing and Documentation, Wageningen, Netherlands. 416 pp.

Other references

  • Agnaniet, H., Menut, C. & Bessière, J.M., 2004. Aromatic plants of tropical Central Africa. Part LII. Comparative study of the volatile constituents from barks of four Annonaceae species growing in Gabon. Journal of Essential Oil-bearing Plants 7(3): 201–209.
  • Atindehou, K.K., Koné, M., Terreaux, C., Traoré, D., Hostettmann, K. & Dosso, M., 2002. Evaluation of the antimicrobial potential of medicinal plants from the Ivory Coast. Phytotherapy Research 16(5): 497–502.
  • Aubréville, A., 1959. La flore forestière de la Côte d’Ivoire. Deuxième édition révisée. Tome premier. Publication No 15. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 369 pp.
  • Chatrou, L.W., Koek-Noorman, J. & Maas, P.J.M., 2000. Studies in Annonaceae XXXVI. The Duguetia alliance: Where the ways part. Annals of the Missouri Botanical Garden 87(2): 234–245.
  • Cooper, G.P. & Record, S.J., 1931. The evergreen forests of Liberia. School of Forestry, Yale University, Bulletin 31, New Haven, United States. 153 pp.
  • de la Mensbruge, G., 1966. La germination et les plantules des essences arborées de la forêt dense humide de la Côte d’Ivoire. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 389 pp.
  • de Saint-Aubin, G., 1963. La forêt du Gabon. Publication No 21 du Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 208 pp.
  • Hawthorne, W.D., 1995. Ecological profiles of Ghanaian forest trees. Tropical Forestry Papers 29. Oxford Forestry Institute, Department of Plant Sciences, University of Oxford, United Kingdom. 345 pp.
  • Hawthorne, W. & Jongkind, C., 2006. Woody plants of western African forests: a guide to the forest trees, shrubs and lianes from Senegal to Ghana. Kew Publishing, Royal Botanic Gardens, Kew, United Kingdom. 1023 pp.
  • Irvine, F.R., 1961. Woody plants of Ghana, with special reference to their uses. Oxford University Press, London, United Kingdom. 868 pp.
  • Koona, P. & Bouda, H., 2004. Activity of 2,4,5-trimethoxystyrene from Pachypodanthium staudtii against two stored product pests. Tropical Science 44(3): 120–123.
  • Kryn, J.M. & Fobes, E.W., 1959. The woods of Liberia. Report 2159. USDA Forest Service, Forest Products Laboratory, Madison, Wisconsin, United States. 147 pp.
  • Kunkel, G., 1965. The trees of Liberia. Field notes on the more important trees of the Liberian forests, and a field identification key. Report No 3 of the German Forestry Mission to Liberia. Bayerischer Landwirtschaftsverlag, München, Basel, Wien. 270 pp.
  • Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
  • Normand, D. & Paquis, J., 1976. Manuel d’identification des bois commerciaux. Tome 2. Afrique guinéo-congolaise. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 335 pp.
  • Raponda-Walker, A. & Sillans, R., 1961. Les plantes utiles du Gabon. Paul Lechevalier, Paris, France. 614 pp.
  • Savill, P.S. & Fox, J.E.D., 1967. Trees of Sierra Leone. Forest Department, Freetown, Sierra Leone. 316 pp.
  • Tailfer, Y., 1989. La forêt dense d’Afrique centrale. Identification pratique des principaux arbres. Tome 2. CTA, Wageningen, Pays-Bas. pp. 465–1271.
  • White, L. & Abernethy, K., 1997. A guide to the vegetation of the Lopé Reserve, Gabon. 2nd edition. Wildlife Conservation Society, New York, United States. 224 pp.
  • Wilks, C. & Issembé, Y., 2000. Les arbres de la Guinée Equatoriale: Guide pratique d’identification: région continentale. Projet CUREF, Bata, Guinée Equatoriale. 546 pp.

Sources of illustration

  • Voorhoeve, A.G., 1979. Liberian high forest trees. A systematic botanical study of the 75 most important or frequent high forest trees, with reference to numerous related species. Agricultural Research Reports 652, 2nd Impression. Centre for Agricultural Publishing and Documentation, Wageningen, Netherlands. 416 pp.
  • Wilks, C. & Issembé, Y., 2000. Les arbres de la Guinée Equatoriale: Guide pratique d’identification: région continentale. Projet CUREF, Bata, Guinée Equatoriale. 546 pp.

Author(s)

  • R.B. Jiofack Tafokou, Ecologic Museum of Cameroon, P.O. Box 8038, Yaoundé, Cameroon
  • S. Konsala, Institut Supérieur du Sahel, Université de Maroua, B.P. 46, Maroua, Cameroon

Correct citation of this article

Jiofack Tafokou, R.B. & Konsala, S., 2012. Duguetia staudtii (Engl. & Diels) Chatrou. [Internet] Record from PROTA4U. Lemmens, R.H.M.J., Louppe, D. & Oteng-Amoako, A.A. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands.

Accessed 24 October 2019.