Prota 16: Fibres/Plantes ΰ fibres
Kew Bull. 1951: 336 (1952).
Dioncophyllum dawei Hutch. & Dalziel (1927).
Origin and geographic distribution
Habropetalum dawei occurs in a 6580 km long stretch along the coast in south-eastern Sierra Leone bordering Liberia. A recent single collection from Gabon needs confirmation.
The stems serve as binding material and are used for tying house-posts. Split stems are considered good rope. Kwako people tie up their bundles of high quality piassava (Raphia spp.) with this material as a sort of trade-mark.
The leaves or the whole plant are used as a fish poison. The young pounded leaves mixed with palm oil are applied to the affected foot to kill jiggers. The plant is very floriferous and showy when in flower.
Production and international trade
Habropetalum dawei is only used locally.
A phenol, present in the plant in a high concentration, has been found to kill fish at dilutions down to 10 ppm. Later, (+)-isoshinanolone isolated from an aqueous extract of the leaves was found to have fish-stunning activity. An acidified aqueous extract of the leaves yielded the benzofuran 2-methylbenzofuran-4-carboxaldehyde (habropetalal). It has strong bactericidal activity against Staphylococcus albus and Escherichia coli and fungicidal activity against Mucor racemosus.
Habropetalum dawei and other Dioncophyllaceae contain naphthyl-isoquinoline alkaloids with promising antimalarial and anti HIV properties. Habropetaline A (5-O-methyldioncopeltine A) and 1,2,3,4-tetrahydro-1,3-dimethyl-8-isoquinolinol have been isolated from crude stem extract. Habropetaline A exhibits strong activity against Plasmodium falciparum, but is inactive against Trypanosoma brucei rhodesiense, Trypanosoma cruzi and Leishmania donovani. It also has some fish-stunning activity. The leaves also contain the related habropetaloic acid.
A scandent or lianous soft-woody shrub attaining up to 10 m tall; branches terete, slightly striate, rusty velvety. Leaves alternate, simple; petiole c. 1 cm long, broad with narrow wings, not articulate; blade elongate-oblong, 1245 cm Χ 2.55.5 cm, cuneate at the base, obtuse at the apex, thin-leathery, glabrous, veins from prominent midrib numerous, parallel, straight, thin, midrib extending into a prominent forked acumen with strongly recurved arms. Inflorescence a somewhat supra-axillary or terminal cyme, rusty velvety, densely flowered; peduncle c. 4 mm in diameter; bracts ovate-elliptical, up to 2 cm long, conspicuous. Flowers bisexual, actinomorphic, white; pedicel up to 4 mm in diameter; sepals 5, lanceolate-elliptical, 11.5 cm long, shortly connate at base; petals 5, free, spatulate-obovate, twice as large as sepals, white, very thin; stamens 10, unequal, filaments thin, anthers ellipsoid; ovary superior, obovoid, small, with 2 thread-like styles and head-shaped stigmas. Fruit a 2-valved capsule opening very early and well before maturity, with persistent calyx; valves small, c. 8 mm across at maturity; funicules 12 per valve, strongly elongated and thickened at maturity, up to 4 cm Χ 4 mm. Seed hanging from the open valves of the fruit, developing in the open, discoid, 4.59 cm in diameter, 23 cm thick, peltately attached to funicle, woody but light, with 12.5(3) cm wide wing.
Flowers open in the early morning and fall before noon, or they open in the late afternoon and fall the next morning. They are visited by bees.
Dioncophyllaceae is a small family in the Caryophyllales s.l. comprising 3 genera in tropical West and Central Africa. Habropetalum is monotypic. Caryophyllales comprises, among others, several carnivorous families. In most Dioncophyllaceae, including Habropetalum dawei, this character is believed to be secondarily lost.
Habropetalum dawei occurs mostly in open, regularly flooded places in scrub, wooded or forested areas, usually on sandy coastal soil near the beach, in association with Ochna multiflora DC., Hymenocardia lyrata Tul. and Hymenocardia heudelotii Muell.Arg.
Seeds germinated in cultivation and plants have grown for a few years, but cultivation is very difficult. In the wild, the flowers are often damaged by a lepidopterous pest and fruits and seeds are rarely found.
Genetic resources and breeding
Habropetalum dawei is believed to be a typical palaeoendemic with restricted distribution and reduced genetic plasticity, in the process of speciation. Although Habropetalum dawei is endemic to a small area, it is fairly common and not listed in the IUCN Red list of endangered species.
Habropetalum dawei will probably remain of only local use as a fibre plant. Recent information on its antimalaria and other medicinal properties is promising, but similar chemical compounds from related plants, especially Ancistrocladus korupensis D.W.Thomas & Gereau (Ancistrocladaceae) seem to have more direct pharmaceutical potential.
Airy Shaw, H.K., 1951. On the Dioncophyllaceae, a remarkable new family of flowering plants. Kew Bulletin 1951: 327347.
Bringmann, G., Messer, K., Schwφbel, B., Brun, R. & Akι Assi, L., 2003. Habropetaline A, an antimalarial naphthylisoquinoline alkaloid from Triphyophyllum peltatum. Phytochemistry 62(3): 345349.
Hanson, S.W., 1977. Local plants of medicinal interest. Part 4: Habropetalum dawei. Chemistry in Sierra Leone 4: 3840.
Hanson, S.W., Crawford, M. & Thanasingh, D.P.J., 1981. (+)-Isoshinanolone and 2 methylbenzofuran-4-carbaldehyde from the fish-stunning plant Habropetalum dawei. Phytochemistry 20: 1162.
Keay, R.W.J., 1954. Dioncophyllaceae. In: Keay, R.W.J. (Editor). Flora of West Tropical Africa. Volume 1, part 1. 2nd Edition. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. pp. 191194.
Bringmann, G., Messer, K., Wohlfarth, M., Kraus, J., Dumbuya, K. & Rueckert, M., 1999. HPLC CD on-line coupling in combination with HPLC-NMR and HPLC-MS/MS for the determination of the full absolute stereostructure of new metabolites in plant extracts. Analytical Chemistry 71(14): 26782686.
Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families AD. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 960 pp.
Gottwald, H. & Parameswaran, N., 1968. Das sekundδre Xylem und die systematische Stellung der Ancistrocladaceae und Dioncophyllaceae. Botanische Jahrbuecher fuer Systematik, Pflanzengeschichte und Pflanzengeographie 88: 4969.
Heubl, G., Bringmann, G. & Meimberg, H., 2006. Molecular phylogeny and character evolution of carnivorous plant families in Caryophyllales revisited. Plant Biology 8(6): 821830.
Hutchinson, J. & Dalziel, J.M., 1928. Tropical African Plants II. Bulletin of Miscellaneous Information Kew 1928(1): 2232.
Kubitzki, K. & Bayer, C., 2003. Families and genera of vascular plants. Vol. 5. Flowering plants, dicotyledons : Malvales, Capparales and non-betalain Caryophyllales. Springer, Berlin, Germany. 418 pp.
Meimberg, H., Dittrich, P., Bringmann, G., Schlauer, J. & Heubl, G., 2000. Molecular phylogeny of Caryophyllidae s.l. based on matK sequences with special emphasis on carnivorous taxa. Plant Biology 2: 218228.
Metcalfe, C.R., 1951. The anatomical structure of the Dioncophyllaceae in relation to the taxonomic affinities of the family. Kew Bulletin 3: 351368.
Missouri Botanical Garden, undated. VAST (VAScular Tropicos) nomenclatural database. [Internet] http://mobot.mobot.org/ W3T/Search/ vast.html. Accessed March 2010.
Neuwinger, H.D., 2004. Plants used for poison fishing in tropical Africa. Toxicon 44(4): 417430.
Correct citation of this article:
Oyen, L.P.A., 2010. Habropetalum dawei (Hutch. & Dalziel) Airy Shaw. In: Brink, M. & Achigan-Dako, E.G. (Editors). Prota 16: Fibres/Plantes ΰ fibres. [CD-Rom]. PROTA, Wageningen, Netherlands.