Laportea (PROSEA)
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Introduction |
Laportea Gaudich.
- Protologue: in Freyc., Voy. Uranie: 498 (1830).
- Family: Urticaceae
- Chromosome number: x= 10; L. bulbifera: 2n= 20, 60
Major species
- Laportea decumana (Roxb.) Wedd.,
- L. interrupta (L.) Chew.
Origin and geographic distribution
Laportea comprises about 22 species, centred in Africa and Madagascar; 3 species are pantropical. In Malesia, 5 species are found.
Uses
The use of leaves or twigs of various Laportea in poulticing as an analgesic can be largely ascribed to the irritating hairs. A decoction is taken as a diuretic. In Bougainville Island (Papua New Guinea) the root and stem bark of L. aestuans or the closely resembling L. ruderalis (J.G. Forster) Chew are externally applied to sores on the sole of feet. In Nigeria, L. aestuans is used to treat burns and whitlow. In India, L. interrupta is used as a mild irritating rubefacient to treat alopecia by intensifying the capillary blood flow, and keeping the scalp and the hair follicles active.
Production and international trade
Laportea is only used on a local scale.
Properties
Both aqueous and ethanol extracts of the leaves of L. interrupta show strong nematicidal activity against Meloidogyne incognita larvae.
The methanol extract of L. aestuans, before and after filtering through charcoal, and various fractions were assayed against 12 species of pathogenic bacteria and fungi. Extracts were active against 7 of these, especially Staphylococcus aureus. In subsequent phytochemical screenings, reactions were positive for steroids, but negative for alkaloids, flavonoids and anthraquinones.
Description
- Monoecious, rarely dioecious herbs or shrubs with irritant hairs.
- Leaves alternate, simple, variously dentate, chartaceous; petiolate; stipules intrapetiolar, partially connate, bifid.
- Inflorescence axillary, paniculate, pedunculate.
- Flowers in loose glomerules, pedicels winged; male flowers tepals 4-5, stamens 4-5, filaments reflexed, pistillode small; female flowers, tepals 4, the dorsiventral ones unequal, smaller than the lateral ones, ovary superior, ovoid, style linear, rarely bush-like, staminodes absent.
- Fruit an achene, compressed, ovoid to hemispherical, sessile or stipitate, reflexed.
Growth and development
Most Laportea species flower and fruit with no particular seasonality.
Other botanical information
Laportea comprises 2 sections: Laportea with 10 species and Fleurya with 12 species. In section Laportea the female pedicels are winged laterally. Laportea is closely related to Nanocnide, the latter differs in its erect achenes, and the free and lateral stipules.
Ecology
The majority of Malesian species, L. aestuans, L. decumana, L. interrupta and L. ruderalis, prefer tropical lowland conditions. However, L. bulbifera (Siebold & Zucc.) Chew has a great climatic tolerance and is found from cool temperate northern China throughout South-East Asia to Sumatra and Java, where it prefers highlands above 1000 m altitude.
Propagation and planting
Laportea can be propagated from seed. In the vicinity of villages plants are sometimes tended for daily use.
Diseases and pests
In Costa Rica L. aestuans is a host for Meloidogyne incognita, a local pest in banana plantations.
Harvesting
Leaves or roots of Laportea are collected from the wild or from tended plants whenever needed.
Handling after harvest
All plant parts of Laportea are usually used fresh.
Genetic resources and breeding
All Laportea species described here have a large area of distribution; several species are common in disturbed habitats, and they do not seem to be at risk of genetic erosion.
Prospects
Very little information is available about the phytochemistry (only screening) and pharmacology of Laportea. More research is therefore needed in order to evaluate its potential.
Literature
- Adebajo, A.C., Aladesanmi, A.J. & Oloke, K., 1991. Antimicrobial activity of Laportea aestuans. Fitoterapia 62(6): 504-505.
- Chew, W.-L., 1969. A monograph of Laportea (Urticaceae). The Gardens’ Bulletin Singapore 25(1): 111-177.
- Chew, W.-L., 1989. Urticaceae. In: George, A.S. (Editor): Flora of Australia. Vol. 3. Hamamelidales to Casuarinales. Australian Government Publishing Service, Canberra, Australia. pp. 68-93.
- Mukherjee, S.N. & Sukul, N.C., 1978. Nematicidal action of three species of wild herbs. Journal of Research, India 2(2): 12.
- Perry, L.M., 1980. Medicinal plants of East and Southeast Asia. Attributed properties and uses. MIT Press, Cambridge, Massachusetts, United States & London, United Kingdom. p. 421.
- Wadhwa, B.M., 1999. Urticaceae. In: Dassanayake, M.D. & Clayton, W.D. (Editors): A revised handbook to the flora of Ceylon. Vol. 13. A.A. Balkema, Rotterdam, the Netherlands & Brookfield, United States. pp. 232-284.
Selection of species
Authors
- J.L.C.H. van Valkenburg
