1052

12(2): Medicinal and poisonous plants 2

Dendrocnide Miq.

Pl. jungh.: 29 (1851).

URTICACEAE

x = unknown

Major species Dendrocnide meyeniana (Walp.) Chew, Dendrocnide stimulans (L.f.) Chew.

Nettle tree (En).

Dendrocnide comprises about 37 species and is found from India, Sri Lanka, China, throughout South-East Asia to Australia and the Pacific islands.

The use of leaves or twigs of various Dendrocnide in poulticing as an analgesic can be largely ascribed to the irritating hairs. Sap or a decoction from the bark or other parts are taken for pulmonary and intestinal disorders without particular indication of their effectiveness. Likewise a herbal tea from the leaves is taken in some regions as a remedy to counteract the irritation caused by the hairs. The bark is occasionally used to make ropes. The soft wood is only suitable for firewood.

Dendrocnide is only used at a local scale.

An aqueous suspension of the root of Dendrocnide stimulans showed strong inhibitory activity against Staphylococcus aureus in vitro. Many Dendrocnide species cause irritation or stings of varying intensity and duration following cutaneous contact.
In addition, Dendrocnide moroides (Wedd.) Chew from Australia, which is also reputed for its stinging hairs is known to contain moroidin. This bicyclic octapeptide, containing an unusual C-N linkage between tryptophan and histidine, was first isolated from the leaves and stalks of Dendrocnide moroides and subsequently shown to be the principle responsible for the long duration of the stings. Although no further phytochemical or pharmacological information is available for the Malesian species, the presence of compounds such as, or related to moroidin cannot be excluded.

Dioecious or monoecious evergreen shrubs or trees up to 15(—35) m tall; stem in general softwooded; normally with irritant hairs. Leaves alternate, simple, coriaceous, crenulate, undulate to smooth; petiolate; stipules intrapetiolar, entirely connate, coriaceous. Inflorescence axillary, racemose or paniculate, bracteate, pedunculate. Flowers free, sessile to pedicellate, pedicel swollen or not, in small fascicles or on flabellate receptacles. Male flowers: tepals 4(—5); stamens 4(—5); pistillode present. Female flowers: flabellately or distichously arranged or in loose fascicles, tepals 4; ovary superior, ovoid, unilocular, stigmas usually ligulate; staminodes absent. Fruit an achene, compressed or ellipsoidal to ovoid, not chartaceous, usually strongly warted.

Branching of Dendrocnide is sympodial, and much like that of Terminalia, with the leaves often forming rosettes at the end of the twigs. Most species flower and fruit with no particular seasonality. Seed of Australian Dendrocnide remains viable on the forest floor for about 5 years.

Dendrocnide comprises 2 sections: Sarcopus with 27 species is found from India and China throughout South-East Asia to Australia and the South Pacific with its major centre in New Guinea, and Dendrocnide with 10 species confined to China, some parts of mainland South-East Asia and western Malesia as far as the Moluccas with its major centre in the Philippines. In the absence of voucher specimens, the identity of the plants for which uses are mentioned can sometimes be considered doubtful in view of their indicated natural distribution.

Dendrocnide are essentially lowland primary forest species preferring slightly moist and somewhat shady habitats. Some prefer limestones and their derived soils. Many of the New Guinea species seem tolerant of secondary forest and abandoned vegetable gardens.

Dendrocnide can easily be propagated from seed. Detached branches of Dendrocnide sinuata that become buried resprout easily.

Leaves, bark or roots of Dendrocnide are collected from wild plants whenever needed.

All plant parts of Dendrocnide are usually used fresh.

All Dendrocnide species treated here have a large area of distribution, and do not seem to be at risk of genetic erosion.

Very little information is available about the phytochemistry and pharmacology of Dendrocnide. More research will therefore be needed to evaluate its possible potential.

Chew, W.-L., 1969. A monograph of Dendrocnide (Urticaceae). The Gardens= Bulletin Singapore 25(1): 1—104.
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.
Grosvenor, P.W., Supriono, A. & Gray, D.O., 1995. Medicinal plants from Riau Province, Sumatra, Indonesia. Part 2: Antibacterial and antifungal activity. Journal of Ethnopharmacology 45: 97—111.
Oelrichs, P.B., Williams, D.H., James, L.F., Keeler, R.F., Bailey, E.M., Cheeke, P.R. & Hegarty, M.P., 1992. Isolation and identification of the pain-producing peptide moroidin from Dendrocnide moroides (Laportea). In: Poisonous plants. Proceedings of the Third International Symposium. Iowa Sate University Press, Ames, Iowa, United States. pp. 556—560.
Perry, L.M., 1980. Medicinal plants of East and Southeast Asia. Attributed properties and uses. MIT Press, Cambridge, Massachusetts, United States & London, United Kingdom. pp. 420—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.

J.L.C.H. van Valkenburg

Dendrocnide amplissima
Dendrocnide latifolia
Dendrocnide meyeniana
Dendrocnide sinuata
Dendrocnide stimulans

van Valkenburg, J.L.C.H., 2001. Dendrocnide Miq.. In: van Valkenburg, J.L.C.H. and Bunyapraphatsara, N. (Editors): Plant Resources of South-East Asia No 12(2): Medicinal and poisonous plants 2. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea

The following species in this genus are important in this commodity group and are treated separatedly in this database:
Dendrocnide amplissima
Dendrocnide latifolia
Dendrocnide meyeniana
Dendrocnide sinuata
Dendrocnide stimulans