Prota 11(1): Medicinal plants/Plantes m้dicinales 1
Hook., Niger Fl.: 447 (1849).
2n = 22
Conopharyngia crassa (Benth.) Stapf (1902), Conopharyngia durissima (Stapf) Stapf (1902).
Adams apple flower (En).
Origin and geographic distribution
Tabernaemontana crassa occurs in humid tropical Africa, from Sierra Leone east to the Central African Republic and eastern DR Congo, and southwards to northern Angola.
In West Africa pulped leaves and latex from the stem and bark of Tabernaemontana crassa have several uses, the main ones being as a local anaesthetic, e.g. to treat dislocated bones or headache, for the treatment of wounds, sores, abscesses and furuncles, and to treat dermal infections such as filaria, ringworm and fungal infections. The latex is also applied as a haemostatic, as it forms a film over the wound. It is taken internally as an anthelmintic. In C๔te dIvoire 12 drops are instilled in the nose to soothe headache, acting as a counter-irritant on the nasal mucosae. The latex is also used as a sedative to calm fits of insanity. A decoction of the leaves is taken as a tonic, appetizer and aphrodisiac, while a bark decoction is given as enema to treat kidney troubles, rheumatism and persistent constipation. A leaf decoction is also used as a massage against rickets in children and to combat fatigue in adults. In Cameroon and the Central African Republic a leaf decoction is taken against fever. In the Central African Republic a drop of latex of the twigs or roots is put in the eye to treat conjunctivitis or ophthalmia, in spite of its strongly caustic properties. A root or stem bark decoction is used for nose drops to treat colds or sinusitis, or a vapour bath is taken with a leaf decoction. Like many lactiferous plants, the latex is considered to be galactagogue in Congo and DR Congo. In C๔te dIvoire and the Central African Republic the latex is an ingredient of an arrow poison. A bark decoction is taken in Congo to treat haematuria and gonorrhoea. In DR Congo a decoction or maceration of the fruit is used as an enema to treat testicular swellings. A decoction of the stem bark is taken to treat diarrhoea.
Large leaves are woven into thatched roofs of houses in Gabon in the belief that their bitter taste keeps away cockroaches. The wood is suitable for general carpentry, plywood and boxboards. It is occasionally used in Liberia to make rice mortars. The bark latex produces an inferior rubber that remains sticky and which has been used occasionally. The plant is considered ornamental, because its flowers are showy and sweet scented. The leaves are eaten by the cultivated edible tiger snail Achatina achatina.
Production and international trade
Powdered bark is traded internationally in herbal medicine shops.
A considerable number of indole alkaloids has been identified in the stem bark, root bark and seeds of Tabernaemontana crassa. Most alkaloids isolated are monomers, mainly of the ibogan class, and a few of the corynanthean class, aspidospermatan class or plumeran class. The dimeric alkaloids conodurine and conoduramine of the corynanthean-ibogan-class have been isolated from the root bark and stem bark, while the stem bark also contains gabunine. The main monomeric alkaloids from the stem bark and root bark are the ibogan class alkaloids coronaridine and its mono- and di-methoxy derivatives isovoacangine and conopharyngine, and the aspidospermatan-class apparicine. The stem bark contains further minor amounts of ibogan class alkaloids, including crassinine, ibogamine and coronaridine and derivatives, as well as corynanthean class alkaloids, including akuammidine, perivine, vobasine and derivatives. The seeds are also rich in alkaloids, the main being the ibogan class coronaridine and coronaridine-hydroxyindolenine and the plumeran class tabersonine.
The plant is very toxic: a single injected dose of the crude ethanol extract of the stem bark or root bark killed rats in 30 minutes. The extract caused dilation of the pupils, decreased motor activity and caused muscle relaxation. Several laboratory tests with guinea pigs or frogs showed that a hot water extract of the aerial parts had stronger local anaesthetic activity than procaine, which was primarily used in dentistry before more effective alternatives were developed. The ethanolic stem bark extract showed significant activity against gram-positive bacteria, while leaf extract showed significant activity against amoeba.
The alkaloids present in major amounts have a variety of pharmacological effects.
Coronaridine and conopharyngine exhibit central nervous system stimulant effects. In regular doses, conopharyngine has hypotensive properties, causes bradycardia and decreases body temperature. High doses of ibogaine, ibogamine and voacangine produce convulsions and asphyxia. Coronaridine showed diuresis and significant hypoglycaemic activity in rats. In mice it is an effective antifertility agent because of its oestrogenic activity. It also has leishmanicidal activity. Furthermore, apparicine, conopharyngine, coronaridine and perivine have local analgaesic activity. The monomers apparacine, coronaridine and the dimers conodurine and gabunine showed significant cytotoxicity against P-388 lymphocytic leukaemia cell cultures. Conoduramine, conodurine and apparicine also showed moderate to strong antibacterial activity against several human pathogens, while apparicine also showed strong activity against type III poliovirus (HPV-3).
The latex is extremely caustic: one drop in the eye may cause blindness.
The wood is yellowish white, moderately hard and easy to work, and it finishes smoothly. It is not resistant to fungal decay.
Adulterations and substitutes
Indolic alkaloids of the classes found in Tabernaemontana are also found in other Apocynaceae genera, e.g. Alstonia, Cabucala, Catharanthus, Hunteria, Ochrosia, Picralima, Rauvolfia, Tabernanthe and Voacanga.
Shrub or small tree up to 15 m tall, glabrous, dichotomously branched; trunk up to 30 cm in diameter, large trees sometimes with buttresses; bark pale to dark grey-brown or brown, with large lenticels. Leaves opposite, simple and entire; ocrea conspicuous, widened into stipules in axils of petioles; petiole 525 mm long; blade broadly to narrowly elliptical, 1046 cm ื 325 cm, base cuneate or rounded, apex acuminate to acute, obtuse or rounded, leathery, pinnately veined with 717 pairs of lateral veins. Inflorescence a corymb 1030 cm long, 2 together in the forks of the branches, rather lax to congested, many-flowered; peduncle 3.511.5 cm long, rather robust; bracts scale-like to sepal-like, leaving a conspicuous scar. Flowers bisexual, regular, 5-merous, sweet-scented; pedicel 320 mm long; sepals almost free, orbicular to broadly ovate, 2.58 mm long, fleshy, ciliate; corolla tube almost cylindrical, 3.510 cm long, fleshy, pale green, twisted at base, hairy inside from 010 mm below the mouth till the insertion of the stamens, throat pale yellow, lobes obliquely elliptical, 2455 mm ื 620 mm, with rounded or obtuse apex, twisted, undulate near apex, spreading and recurved later, white to pale yellow; stamens inserted 814 mm from the corolla base, included, anthers sessile, narrowly triangular, 913 mm long; ovary superior, almost cylindrical to ovoid, consisting of 2 carpels, connate at the base, styles fused, 28 mm long, pistil head almost cylindrical, 33.5 mm long, widened at the apex into 5 orbicular lobes, overtopped by 2 triangular peaks, widened at the base into a ring. Fruit consisting of 2 separate obliquely globose follicles 512 cm in diameter, pale green or glaucous, 2-valved, several- to many-seeded. Seeds obliquely ellipsoid, 8.514 mm long, with up to 8 longitudinal grooves, minutely warty, dark brown, aril white. Seedling with epigeal germination.
Other botanical information
Tabernaemontana comprises about 110 species and is pantropical. About 18 species occur in mainland Africa and 15 in Madagascar. It is closely related to Voacanga. Along the coast, the corolla tube of Tabernaemontana crassa is shorter, 3545 mm long, whereas in other areas it is 60100 mm long. Tabernaemontana crassa is closely allied to Tabernaemontana africana Hook., which can be distinguished by its stamens inserted at 2545 mm from the corolla base, wider corolla tube and yellow to orange follicles.
Tabernaemontana stenosiphon Stapf is an endemic tree of Sใo Tom้. The latex induces vomiting and is also used as a purgative. The root decoction is a tonic and febrifuge. The tree has been planted in Nigeria for the production of rubber.
The liana Tabernaemontana eglandulosa Stapf occurs in West and Central Africa. In the Central African Republic the leaves or twig bark are chewed and the juice swallowed to combat migraine. In DR Congo the roots are used to treat snakebites. The sap mixed with water used as eye drops to cure headache. The pounded root is a component of arrow poison. The latex was formerly used as an adulterant for Hevea rubber. All plant parts contain voacangine and coronaridine. The stem bark contains conopharyngine and 6-hydroxy-3-oxocoronaridine. The leaves and twigs contain as major components tacamine, tacamonine, 19-hydroxytacamine and 16-epitacamine (tacaman class), and also voaphylline, tubotaiwine, ibogamine and norfluorocurarine.
Growth and development
Tabernaemontana crassa plants develop according to the architectural growth model of Leeuwenberg determined by a monopodial orthotropic trunk, which ends in a terminal inflorescence. After flowering the 2 uppermost axillary buds develop into branches, so that the growth is sympodial; the infructescence seems to be axillary. Tabernaemontana crassa can be found flowering and fruiting throughout the year. Fruits are mature after 1 year.
Tabernaemontana crassa occurs widely in the understorey of open forest, forest clearings or bush, also along the coast, less often in gallery forest, from sea-level up to 2000 m altitude.
Propagation and planting
Tabernaemontana crassa can be propagated by seed and probably also by semi-ripe cuttings.
The bark of Tabernaemontana crassa is stripped from the trunk. Leaves are harvested whenever the need arises.
Tabernaemontana crassa has a fairly large area of distribution and is therefore not likely to be threatened by genetic erosion.
Tabernaemontana crassa contains a large number of indole alkaloids with interesting pharmacological activities. The alkaloid content is similar to that of Tabernaemontana pachysiphon, another medicinally important species. Although several individual alkaloids have been tested for their pharmacological activity, more analyses are needed to evaluate their importance.
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van Beek, T.A., Verpoorte, R. & Baerheim Svendsen, A., 1984. Alkaloids of Tabernaemontana eglandulosa. Tetrahedron 40(4): 737748.
van Beek, T.A., de Smidt, C. & Verpoorte, R., 1985. Phytochemical investigation of Tabernaemontana crassa. Journal of Ethnopharmacology 14(23): 315318.
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Agwu, I.E. & Akah, P.A., 1990. Tabernaemontana crassa as a traditional local anaesthetic agent. Journal of Ethnopharmacology 30(1): 115119.
Betti, J.L., 2004. An ethnobotanical study of medicinal plants among the Baka pygmies in the Dja biosphere reserve, Cameroon. African Study Monographs 25(1): 127.
Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families AD. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 960 pp.
Cooper, G.P. & Record, S.J., 1931. The evergreen forests of Liberia. School of Forestry, Yale University, Bulletin 31, New Haven, United States. 153 pp.
Din Belle, D., Tolvanen, A. & Lounasmaa, M., 1996. Total synthesis of tacamine-type indole alkaloids of Tabernaemontana eglandulosa. Tetrahedron 52(34): 1136111378.
Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
Srivastava, S., Singh, M.M. & Kulshreshtha, D.K., 2001. A new alkaloid and other anti-implantation principles from Tabernaemontana heyneana. Planta Medica 67(6): 577579.
van Beek, T.A., 1984. Pharmacognostical studies of some Tabernaemontana species. PhD thesis, University of Leiden, Leiden, Netherlands. 163 pp.
van Beek, T.A. & van Gessel, M.A.J.T., 1988. Alkaloids of Tabernaemontana species. In: Pelletier, S.W. (Editor). Alkaloids: Chemical and biological perspectives. Vol. 6. Wiley, New York, United States. pp. 75226.
Sources of illustration
Leeuwenberg, A.J.M., 1991. A revision of Tabernaemontana 1. The Old World species. Royal Botanic Gardens, Kew, United Kingdom. 223 pp.
Correct citation of this article:
Mairura, F.S. & Schmelzer, G.H., 2006. Tabernaemontana crassa Benth. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes m้dicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
1, flowering branch; 2, corolla; 3, fruit.
Redrawn and adapted by Achmad Satiri Nurhaman