PROTA homepage Prota 11(1): Medicinal plants/Plantes m้dicinales 1
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Adenia digitata (Harv.) Engl.

Protologue
Bot. Jahrb. Syst. 14: 375 (1891).
Family
Passifloraceae
Vernacular names
Wild granadilla (En).
Origin and geographic distribution
Adenia digitata occurs from Tanzania south to South Africa and west to Angola.
Uses
Adenia digitata is deadly poisonous. The Tswana people of Botswana have used the fruit for homicide. The fruit is also eaten or a root extract is drunk as a suicide poison. Accidental poisoning mainly occurs when the root of Adenia digitata is mistaken for edible tubers, particularly those of Coccinia species. Children are often poisoned as a result of eating the attractive fruit. In Botswana the root is rubbed into swellings or applied warm to treat knee swellings. To treat skin ailment, leprosy or ulcers, the Nyanja people of Malawi and Zambia rub the skin with boiled roots or a root decoction. The Venda people of South Africa apply a root decoction externally and also drink it to treat swollen legs.
Because of its impressive tuber, which can be partly above ground, Adenia digitata is cultivated as an ornamental worldwide.
Production and international trade
Adenia digitata is collected, traded and grown as an ornamental by plant amateurs.
Properties
The tuber of Adenia digitata contains cyanogenic glycosides, mainly tetraphyllin B (barterioside), and the very potent toxin modeccin, a toxalbumin, which inhibits protein synthesis in vitro.
Botany
Perennial climbing herb, usually dioecious, with a tuber up to 60 cm in diameter; stems annual, up to 3 m long. Leaves alternate, deeply (3–)5-cleft or -foliolate, orbicular in outline; stipules narrowly triangular, 1–3 mm long, withering; petiole 1–9 cm long; lobes or leaflets ovate to obovate or linear, sometimes deeply lobed, 1.5–15 cm ื 1–4(–7) cm, rounded to acute at apex, with glands at base. Inflorescence an axillary cyme, with a 2–10 cm long tendril between the branches, 1–20(–60)-flowered; peduncle up to 7 cm long. Flowers usually unisexual, regular, 5-merous; pedicel up to 3 cm long, jointed about halfway; calyx tube about as long as lobes; petals free, included in calyx, usually toothed; male flowers up to 2.5 cm long, filaments of stamens fused in lower half and anthers curved inward and clinging together, ovary rudimentary; female flowers up to 2 cm long, ovary superior, ovoid to oblong, styles 3, fused at base, stigmas kidney-shaped, stamens rudimentary. Fruit a stalked ovoid to ellipsoid capsule 3–5.5(–7.5) cm ื 2–4 cm, smooth, orange to yellow when ripe, many-seeded. Seeds ovoid to ellipsoid, flattened, 6–8 mm ื 4.5–6.5 mm ื 3 mm, brown, pitted.
Adenia comprises about 95 species, with about 60 species on the African continent, 20 in Madagascar and 15 in Asia. The genus is subdivided in 6 sections. Adenia digitata is classified in section Blepharanthes. Adenia repanda (Burch.) Engl. from section Paschanthus also occurs in southern Africa, from Angola east to Zimbabwe and south to South Africa, and is reported to be deadly poisonous to man. However, Adenia repanda is also reported to be greedily eaten by livestock.
Ecology
Adenia digitata occurs in savanna, bushland, dry rocky or grassy localities, on termite mounds and along forest fringes, on stony, sandy, or clayish soils from sea-level up to 1850 m altitude.
Genetic resources and breeding
Adenia digitata is widely distributed and hence not threatened with genetic erosion.
Prospects
It seems likely that medicinal use of Adenia digitata will remain limited in Africa, because of the high toxicity. The chemotherapeutic properties of lectins such as modeccin in cancer treatment and in chemoprevention warrant further research on medicinal applications. The prospects for Adenia digitata as an ornamental seem promising because of the growing interest in unusual plants by specialized amateurs.
Major references
• Arnold, H.J. & Gulumian, M., 1984. Pharmacopoeia of traditional medicine in Venda. Journal of Ethnopharmacology 12: 35–74.
• de Wilde, W.J.J.O., 1971. A monograph of the genus Adenia Forsk. (Passifloraceae). Mededelingen Landbouwhogeschool Wageningen 71–18. Wageningen, Netherlands. 281 pp.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• van Wyk, B.E., van Heerden, F. & van Oudtshoorn, B., 2002. Poisonous plants of South Africa. Briza Publications, Pretoria, South Africa. 288 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.
Other references
• Bokan, S., 2004. An evaluation of toxins and bioregulators as terrorism and warfare agents. NATO Science Series, Series I: Life and Behavioural Sciences 356 (Toxicogenomics and Proteomics): 147–157.
• de Wilde, W.J.J.O., 1975. Passifloraceae. In: Polhill, R.M. (Editor). Flora of Tropical East Africa. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. 71 pp.
• Gasperi-Campani, A., Barbieri, L., Lorenzoni, E., Montanaro, L., Sperti, S., Bonetti, E. & Stirpe, F., 1978. Modeccin, the toxin of Adenia digitata. Purification, toxicity and inhibition of protein synthesis in vitro. Biochemical Journal 174: 491–496.
• Gonzแlez de Mejํa, E. & Prisecaru, V.I., 2005. Lectins as bioactive plant proteins: a potential in cancer treatment. Critical Reviews in Food Science and Nutrition 45: 425–445.
• Muhammad Mansur, 2003. Adenia Forssk. In: Lemmens, R.H.M.J. & Bunyapraphatsara, N. (Editors). Plant Resources of South-East Asia No 12(3). Medicinal and poisonous plants 3. Backhuys Publishers, Leiden, Netherlands. pp. 35–38.
• Pelosi, E., Lubelli, C., Polito, L., Barbieri, L., Bolognesi, A. & Stirpe, F., 2005. Ribosome-inactivating proteins and other lectins from Adenia (Passifloraceae). Toxicon 46(6): 658–663.
Author(s)
• A. de Ruijter
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands


Editors
• G.H. Schmelzer
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
• A. Gurib-Fakim
Faculty of Science, University of Mauritius, R้duit, Mauritius
Associate editors
• C.H. Bosch
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
• M.S.J. Simmonds
Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, United Kingdom
• R. Arroo
Leicester School of Pharmacy, Natural Products Research, De Montfort University, The Gateway, Leicester LE1 9BH, United Kingdom
• A. de Ruijter
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
General editors
• R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
• L.P.A. Oyen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
Photo editor
• A. de Ruijter
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article:
de Ruijter, A., 2007. Adenia digitata (Harv.) Engl. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes m้dicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
inflorescence
obtained from
B. Wursten


flower
obtained from
B. Wursten


fruits
obtained from
B. Wursten


tuber
obtained from
B. Wursten