Pentarrhinum insipidum (PROTA)

Plant Resources of Tropical Africa Introduction

List of species

General importance
Geographic coverage Africa
Geographic coverage World
Fruit
Vegetable
Essential oil / exudate
Medicinal
Forage / feed
Food security

Pentarrhinum insipidum E.Mey.

Protologue: Comm. pl. Afr. austr.: 220 (1837).

Family: Asclepiadaceae (APG: Apocynaceae)

Chromosome number: 2n = 22

Vernacular names

African heartvine (En).

Origin and geographic distribution

Pentarrhinum insipidum is widespread in Namibia, Zimbabwe and South Africa and again in the northern Tanzania-Kenya area, from where it extends into Ethiopia; it is known from one area in Sudan. Between those regions it is rare and has, for example, not yet been collected in northern Zambia or northern Malawi.

Uses

In southern Africa young leaves and fruits are used as raw or cooked vegetables. Sometimes the leaves are pounded with leaves of other species or with the tubers of several small Asclepiadaceae. The young fruits may be stored for 3 weeks before they deteriorate; older fruits (when the seeds inside have turned brown) become too hard to make good eating. They exude a copious amount of harmless latex and have a nutty, slightly peppery flavour.

In Tanzania a decoction of the leaves is used to wash boils, and after washing the boils are covered with hot leaves. In Malawi the roots are said to be used as medicine. The leaves might be a good fodder for domestic stock.

Properties

Pentarrhinum insipidum is certainly not poisonous, although it has been reported occasionally as being so. Fresh leaves contain per 100 g: water 85 g, energy 192 kJ (46 kcal), protein 3.5 g, fat 0.5 g, carbohydrate 6.7 g, fibre 2 g, Ca 370 mg, P 63 mg, Fe 9 mg, thiamin 0.2 mg, riboflavin 0.3 mg, niacin 1 mg, ascorbic acid 16 mg. Fresh young fruits contain per 100 g: water 88 g, energy 157 kJ (37 kcal), protein 2.3 g, fat 0.2 g, carbohydrate 6.6 g, fibre 1.5 g, Ca 72 mg, P 47 mg, Fe 0.8 mg (Arnold, T.H., Wells, M.J. & Wehmeyer, A.S., 1985).

Botany

Perennial, climbing, latex-containing herb, with elongated tuberous roots and strongly branched, annual shoots 2–3 m long, glabrous to sparsely pubescent. Leaves opposite, simple; petiole 2–5 cm long; blade ovate, 2.5–6.5 cm × 2–5 cm, base cuneate to cordate, apex acuminate, margin entire. Inflorescence cymose, 5–15-flowered; peduncle 3–4 cm long. Flowers bisexual, regular, 5-merous, with aromatic scent; pedicel 0.5–2 cm long; calyx rotate, lobes triangular, up to 2.5 mm long, connate at base, pubescent outside; corolla with ovate to oblong lobes up to 6 mm × 3.5 mm, connate at base, fully reflexed at anthesis, margin ciliate, green-yellowish; corona c. 3 mm long, fleshy, at apex with horn-like ornaments; anthers with connective appendages and wings; ovary superior, style apex flat. Fruit a pair of follicles, but usually only one developed, ellipsoid, 5–9 cm × 1.5–2 cm, pale brown, smooth to densely covered with 2–4 mm long protuberances. Seeds ovoid, about 6 mm × 2 mm, brown, margin winged, apex with a coma of 3–4 mm long hairs.

Pentarrhinum comprises about 6 species nowadays, but is likely to become larger as species are being transferred to it from Cynanchum. The other widespread species is Pentarrhinum abyssinicum Decne., which is more widely distributed but more scattered than Pentarrhinum insipidum. In the literature, the name Pentarrhinum insipidum has sometimes erroneously been used for Pentarrhinum abyssinicum.

Ecology

Pentarrhinum insipidum is associated with shrubland and savanna, in dry or well-drained conditions, but does not tolerate extremes of dry and wet. It ranges from sea-level up to 2200 m altitude, but is most common between 600–1600 m.

Management

Pentarrhinum insipidum can easily be grown from seed and is a rapid producer of green material.

Genetic resources

Pentarrhinum insipidum is widespread in East and southern Africa and not in danger of genetic erosion.

Prospects

In southern Africa Pentarrhinum insipidum is an important vegetable from the wild. It is considered to have some potential for development as a commercial vegetable. Its medicinal value needs confirmation.

Major references

• Arnold, T.H., Wells, M.J. & Wehmeyer, A.S., 1985. Khoisan food plants: taxa with potential for future economic exploitation. In: Wickens, G.E., Goodin, J.R. & Field, D.V. (Editors). Plants for arid lands. Proceedings of the Kew international conference on economic plants for arid lands. Allen & Unwin, London, United Kingdom. pp. 69–86.

• Liede, S. & Nicholas, A., 1992. A revision of the genus Pentarrhinum E. Meyer (Asclepiadaceae). Kew Bulletin 47(3): 475–490.

• Story, R., 1958. Some plants used by the bushmen in obtaining food and water. Memoirs of the Botanical Survey of South Africa No 30. 113 pp.

Other references

• 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.

• van Wyk, B.E., van Oudtshoorn, B. & Gericke, N., 1997. Medicinal plants of South Africa. Briza Publications, Pretoria, South Africa. 304 pp.

• Watt, J.M. & Breyer-Brandwijk, M.G., 1962. The medicinal and poisonous plants of southern and eastern Africa. 2nd Edition. E. and S. Livingstone, London, United Kingdom. 1457 pp.

• Williamson, J., 1955. Useful plants of Nyasaland. The Government Printer, Zomba, Nyasaland. 168 pp.

Author(s)

• P.C.M. Jansen

PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article

Jansen, P.C.M., 2004. Pentarrhinum insipidum E.Mey. [Internet] Record from PROTA4U. Grubben, G.J.H. & Denton, O.A. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. <http://www.prota4u.org/search.asp>.

Accessed 18 December 2024.

• See the Prota4U database.