Prota 11(1): Medicinal plants/Plantes médicinales 1
Engl., Pflanzenr. IV, 94: 101 (1910).
Heptacyclum zenkeri Engl. (1899).
Origin and geographic distribution
Penianthus zenkeri occurs in Nigeria and Cameroon and possibly also in DR Congo.
Preparations of the roots of Penianthus zenkeri are used to treat male sexual impotence, cough and wounds. The roots and twigs are used as an aphrodisiac and in the treatment of local infections and venereal diseases. In Cameroon a bitter root decoction is employed as a vermifuge. A dressing made from the leaves is applied to the nails to treat whitlow.
Several pharmacologically active terpenoids, protoberberine alkaloids and aporphine alkaloids have been isolated from Penianthus spp., but no chemical analyses have been done on Penianthus zenkeri; the analyses effected so far relate to the West African Penianthus patulinervis Hutch. & Dalziel.
Dioecious, evergreen shrub to small tree up to 6 m tall, glabrous except the flowers. Leaves arranged spirally, simple and entire; stipules absent; petiole 10–25(–27) cm long, flattened above, swollen at both ends; blade elliptical to oblanceolate, 24–41 cm × 8–15 cm, base cuneate to obtuse, apex long-acuminate, leathery, pinnately veined with 11–19(–21) pairs of looping lateral veins. Inflorescence an umbel, often on older branches, 10–20-flowered; peduncle 4.5–8(–12.5) mm long, enlarging in fruit, sparingly short-hairy; bracts tiny. Flowers unisexual, regular; pedicel 3–7 mm long, enlarging in fruit; male flowers with 7–8 pale yellowish tepals in 3 whorls, 1–2 outer ones triangular, 0.5–1 mm long, short-hairy outside, tepals of middle whorl 3, oblong to obovate, 1.5–2.5(–3) mm long, tepals of inner whorl 3, oblong to obovate, 2.5–3.5 mm long, staminodes 6(–8) in 2 whorls, elliptical to oblong, c. 2 mm long, stamens 6(–7) in 2 whorls, (2–)2.5–3 mm long; female flowers with 7–8 greenish tepals in 3 whorls, 1–2 outer ones narrowly triangular, 0.5–1 mm long, sparsely short-hairy outside, tepals of middle whorl 3, oblong to obovate, 2–2.5 mm long, spreading, tepals of inner whorl 3, oblong to obovate, 2–3 mm long, tepaloid staminodes 6 in 2 whorls, elliptical to obovate, 1.5–2 mm long, stamen-like staminodes 6 in 2 whorls, narrowly triangular, 1–1.5 mm long, ovary superior, consisting of 3 carpels c. 2 mm long, stigma large, sessile, slightly bifid, strongly lobed. Fruit composed of 1–3 drupes, each drupe ellipsoid, 2–4 cm × 1–2 cm, yellow to orange, 1-seeded. Seed ellipsoid, 2–3 cm × c. 1 cm. Seedling with epigeal germination.
Penianthus comprises 4 species and is restricted to humid tropical Africa. Penianthus patulinervis was formerly included in Penianthus zenkeri, but their areas of distribution and morphology are clearly separate; the former occurs in West Africa and the latter occurs in eastern Nigeria and Cameroon. Penianthus zenkeri has many-flowered umbels, pedicellate flowers and longer petioles than Penianthus patulinervis.
Penianthus zenkeri occurs in rainforest undergrowth, occasionally also in semi-deciduous forest, at 300–700 m altitude.
The stone is used for planting, and its scarification promotes germination. Twigs and roots are collected from the wild when required.
Genetic resources and breeding
The area of distribution of Penianthus zenkeri is rather small, its habitat is under pressure and high prices are paid for its products in the market. It is not listed in the IUCN Red List of threatened species, but its diversity should be guarded to ensure sustainable future supplies.
Penianthus zenkeri is widely used in traditional medicine, but its chemistry and pharmacology have not been investigated. Research is therefore warranted.
• Dekker, A.J.F.M., 1983. A revision of the genera Penianthus Miers and Sphenocentrum Pierre (Menispermaceae) of West and Central Africa. Bulletin du Jardin Botanique National de Belgique 53(1–2): 17–66.
• Cheek, M., Pollard, B.J., Darbyshire, L., Onana, J.M. & Wild. C. (Editors), 2004. The Plants of Kupe, Mwanenguba and the Bakossi Mountains: a conservation checklist - with introductory chapters on the physical environment, vegetation, endemics, invasives, phytogeography and refugia, ethnobotany, bryophytes, the macrofungi, the vertebrate fauna, the protected areas system, sacred groves and IUCN Red Data species. Royal Botanical Gardens, Kew, Richmond, United Kingdom. 508 pp.
• Achenbach, H. & Hemrich, H., 1991. Constituents of tropical medicinal-plants .42. Clerodane-type diterpenes and other constituents of Penianthus zenkeri. Phytochemistry 30(6): 1957–1962.
• Burkill, H.M., 1997. The useful plants of West Tropical Africa. 2nd Edition. Volume 4, Families M–R. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 969 pp.
• Troupin, G., 1951. Menispermaceae. In: Robyns, W., Staner, P., Demaret, F., Germain, R., Gilbert, G., Hauman, L., Homès, M., Jurion, F., Lebrun, J., Vanden Abeele, M. & Boutique, R. (Editors). Flore du Congo belge et du Ruanda-Urundi. Spermatophytes. Volume 2. Institut National pour l’Étude Agronomique du Congo belge, Brussels, Belgium. pp. 202–255.
Correct citation of this article:
Tchinda, A.T., 2008. Penianthus zenkeri (Engl.) Diels. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.