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Picralima nitida (Stapf) T.Durand & H.Durand

Protologue
Bull. Jard. Bot. Etat 2: 338 (1910).
Family
Apocynaceae
Chromosome number
2n = 22
Vernacular names
Obéro, demouain à gros fruits, ebam (Fr). Lutete-lumene (Po).
Origin and geographic distribution
Picralima nitida occurs from Côte d’Ivoire east to Uganda and south to DR Congo and Cabinda (Angola).
Uses
Throughout its distribution area the seeds, bark and roots of Picralima nitida have a reputation as a febrifuge and remedy for malaria. They are also extensively used for pain relief and to treat chest and stomach problems, pneumonia and intestinal worms. Usually, the seeds or bark are crushed or chewed and eaten for this purpose, or a decoction from the roots, seeds or bark is drunk.
In Côte d’Ivoire, Benin and Nigeria a bark or root decoction is taken against jaundice, and a leaf decoction is taken by mouth or used as a lotion against measles. The intensely bitter seeds are crushed and eaten with lemon juice to treat hernia, vomiting or diarrhoea. The crushed seeds are applied to abscesses. A paste of pulverized seeds and shea butter is rubbed on the abdomen to treat leucorrhoea in women. In Ghana a decoction of the seeds is employed as an enema and analgesic. The seeds are chewed as a tonic and stimulant. Dry leaves are boiled in water and taken to treat guinea worm. In Cameroon a fruit decoction is taken to cure cough or typhoid fever; in DR Congo the bark is used similarly. In Gabon people from the Pahouin tribe chew a little of the fruit and bark to allay hunger while on long marches in the bush. The bitter bark is boiled with sugar and the decoction is drunk against food poisoning or venereal diseases. In Congo a bark decoction is taken as a purgative or to treat hernia, and with other plants to relieve gonorrhoea. In southern Cameroon and Congo, a bark decoction is drunk to cure sterility in men. Leaf sap is dripped into the ear to treat otitis. The crushed seeds, roots or fruit pulp are also ingredients for arrow poison. In Ghana and DR Congo, immature fruits are pounded and thrown in the water as a fish poison.
The wood, called ebam in trade, is used to make a variety of small utensils, e.g. paddles, shuttles for weaving, dolls, combs, walking sticks, pestles and mortars, incense holders, bows and arrows, spade handles or spoons. Spoons or dippers are also made of the hard shell of the fruit.
Production and international trade
The dried powdered seeds of Picralima nitida are encapsulated and marketed in Ghana under the brand name ‘Picap capsules’ for the treatment of diarrhoea and various types of pain. In Cameroon the seeds, bark and fruits are commonly sold in local markets. In 2002, the market price was about 2400 Fcfa (about US$ 5) for 550 g seed and bark.
Properties
The stem bark, fruit and seeds of Picralima nitida contain as major compounds the indole alkaloids akuammine, akuammicine (strychnan class), akuammidine and akuammiline (both corynanthean class), akuammigine and the very similar alstonine, pseudo-akuammigine and picraline. The seeds are particularly rich in alkaloids (3.5–4.8%); akuammine is the principal alkaloid of the mature seeds, while minor alkaloids are pseudo-akuammicine, picranitine, picratidine (N-methylpicraline), eburnamine (desacetylpicraline) and desacetylakuammiline (rhazimol). The root bark contains akuammigine, akuammicine, picracine and desacetylpicraline, and the leaves akuammine, akuammigine, picraphylline and melinonine A. The stem bark also contains picracine.
Akuammine has strong sympathomimetic and local analgesic activities; its effects are comparable to that of cocaine. It causes marked and lasting hypotension in dogs, without affecting respiration. In higher doses it causes a strong inhibitory effect on intestinal peristaltic movements. At such doses it also has hypertensive activity with a weaker, but longer lasting effect than yohimbine.
Akuammigine shows clear sympatholytic activity and antagonizes the effect of adrenaline on the heart, vessels and regulatory centre of the circulation system. Akuammidine has hypotensive, skeletal muscle relaxant and local analgesic activities. Its local analgesic activity is about 3 times as potent as cocaine. It acts selectively as a sympatholytic, unaccompanied by parasympatholytic effects. It inhibits the irritability of the sympathetic nervous system and opposes akuammine. Pseudo-akuammigine acts as an indirect reversible and competitive parasympathomimetic. In low doses it excites and in high doses it inhibits the central nervous system, respiration, contraction of the skeletal muscles and contraction of the smooth muscles. It increases hexobarbital-induced sleeping time and has local analgesic, anti-inflammatory, cholinesterase-inhibiting and hypotensive activities. Pericine and pericalline, only present in cell suspension cultures of Picralima nitida, showed in vitro opium-antagonist activity.
In tests with mice, alstonine has shown antipsychotic effects in the treatment of schizophrenia, without some of the side effects of the commonly used drug clozapine. Alstonine appears to lack the proconvulsant properties of clozapine.
Extracts of the seeds have analgesic activities comparable to those of morphine in rats. It was demonstrated that the alkaloids akuammidine, akuammine, pseudo-akuammigine and akuammicine possess varying degrees of agonist and antagonist activities at opioid receptors in vitro. Akuammigine showed little or no efficacy in the opioid bioassays. As the analgesic actions are mediated via interaction with opioid receptors, the potential for causing addiction and dependence should also be investigated. The seed extracts showed also significant anti-inflammatory activities in several rat models.
The extracts of roots, stem bark and fruit rind showed highly significant inhibitory effects in vitro against Plasmodium falciparum, including chloroquine-resistant strains, even in low concentrations. The dichloromethane extract of the fruit rind was the most active. The antimalarial activity is also present in the seeds and leaves, but at a lower level. Akuammine showed weak antimalarial activity against chloroquine-resistant Plasmodium strains. The basic fraction of the methanol extract of the stem bark exhibited significant antimicrobial activity against a wide range of gram-positive bacteria and fungi, but limited activity against gram-negative bacteria. The basic fraction had a similar minimum inhibitory concentration (MIC) for Staphylococcus aureus as the control drug ampicillin, and lower MIC values against Aspergillus flavus and Aspergillus niger than those of tiaconazole. In clinical trials, a cream formulation of the methanol extract of the stem bark of Picralima nitida exhibited impressive effectiveness against skin conditions of pityriasis versicolor, tinea pedis interdigitalis (athlete’s foot), tinea capitis (ringworm of the head), and tinea corporis (ringworm of the body). A methanol extract of the stem bark was also found to be active against a visceral Leishmania isolate at concentrations of 50 μg/ml or less. A hot water extract of the stem bark had a significant effect against Trypanosoma brucei, which was statistically comparable to that of diminazene aceturate (Berenil), commonly used in the treatment of sleeping sickness. Bark and seed extracts caused hypoglycaemia in both normal and alloxan-induced diabetic rabbits by a mechanism independent of the availability of insulin from pancreatic β-cells. The seed extract exhibited faster hypoglycaemic activity than the standard drug tolbutamide. Acute toxicity tests in rats showed a dose-dependent acute intraperitoneal toxicity.
The wood is pale yellow, hard and elastic, and polishes and finishes well.
Adulterations and substitutes
In Cameroon the stem bark of Alstonia boonei De Wild. is used by several traditional healers for treating typhoid fever, jaundice and malaria, and is most often used as a substitute for Picralima nitida. The leaves and bark of Thomandersia hensii De Wild. & T.Durand, the leaves and roots of Mangifera indica L. and the roots of Carica papaya L. are sometimes used as antimalarial drugs and febrifuge as a substitute for Picralima nitida. Similar indole alkaloids are found in Tabernaemontana species.
Description
Shrub or tree up to 35 m tall, with white latex in all parts, glabrous; bole up to 60 cm in diameter; bark hard, brittle, pale to dark greyish black or brown, smooth to slightly rough or finely striped. Leaves opposite, simple and entire; stipules absent; petiole 1–2 cm long; blade elliptical to oblong, (5–)10–26 cm × 2–13 cm, base cuneate, apex abruptly acuminate, thickly papery to thinly leathery, pinnately veined with 14–23 pairs of lateral veins. Inflorescence a terminal or sometimes axillary, compound, umbel-like cyme 6–10 cm long, 10–35-flowered; peduncle 2–35 mm long, with 3 primary branches; bracts very small. Flowers bisexual, regular, 5-merous, fragrant or not, open during the day; pedicel 2–20 mm long; sepals almost free, imbricate, broadly ovate to almost orbicular, 5–7 mm long; corolla with fleshy cylindrical tube 25–45 mm long, hairy inside and narrowed below the insertion of the stamens, often greenish, lobes ovate, 14–30 mm × 6–10 mm, apex obtuse, spreading or erect, white to yellow; stamens inserted above the middle of the corolla tube, included, anthers ovate, 3–4 mm long; ovary superior, consisting of 2 separate carpels, united at the extreme base by a disk-like thickening, style slender, 5–7 mm long, pistil head with an oblong basal part and a filiform stigmoid apex up to 1.5 mm long. Fruits consisting of 2 free obovoid to ellipsoid follicles 11–20 cm long, smooth, apex rounded, yellow to orange, 2-valved, several- to many-seeded. Seeds obliquely ovate, obovate to oblong, flattened, 2.5–4.5 cm long, smooth, brown to orange, embedded in soft white to orange pulp. Seedling with epigeal germination; cotyledons ovate to obovate or oblong, 10–13 mm long, base slightly cordate to rounded, apex obtuse to rounded.
Other botanical information
Picralima comprises a single species and is restricted to Africa. It is related to Hunteria and Pleiocarpa.
Anatomy
Wood-anatomical description (IAWA hardwood codes):
Growth rings: 2: growth ring boundaries indistinct or absent. Vessels: 5: wood diffuse-porous; 9: vessels exclusively solitary (90% or more); 13: simple perforation plates; 22: intervessel pits alternate; 23?: shape of alternate pits polygonal; 25: intervessel pits small (4–7 μm); 29: vestured pits; 30: vessel-ray pits with distinct borders; similar to intervessel pits in size and shape throughout the ray cell; (40: mean tangential diameter of vessel lumina 50 μm); 41: mean tangential diameter of vessel lumina 50–100 μm; 48: 20–40 vessels per square millimetre. Tracheids and fibres: (61: fibres with simple to minutely bordered pits); 62: fibres with distinctly bordered pits; 66: non-septate fibres present; (69: fibres thin- to thick-walled); 70: fibres very thick-walled. Axial parenchyma: 76: axial parenchyma diffuse; 77: axial parenchyma diffuse-in-aggregates; 78: axial parenchyma scanty paratracheal; 93: eight ( 5–8) cells per parenchyma strand; 94: over eight cells per parenchyma strand. Rays: (97: ray width 1–3 cells); (98: larger rays commonly 4- to 10-seriate); 108: body ray cells procumbent with over 4 rows of upright and/or square marginal cells; 115: 4–12 rays per mm; 116: 12 rays per mm.
(M. Thiam, P. Détienne & E.A. Wheeler)
Growth and development
Trees growing at the same location generally have the same height and are probably of the same age. Young plants have a high competition capacity. Picralima nitida can be found flowering and fruiting throughout the year. The flowers are visited by insects during sunny days. Fruits of Picralima nitida are eaten by elephants, which disperse the seeds.
Ecology
Picralima nitida is an understorey tree in rainforest, also in mature secondary forest and semi-deciduous forest along river banks, up to 900 m altitude.
Propagation and planting
There are about 300–400 Picralima seeds/kg.
Harvesting
Seeds, bark and other plant parts of Picralima nitida intended for trade or for local medicinal use are collected from wild plants.
Handling after harvest
Picralima nitida seeds can be dried and stored for 0.5–2 years without loss of pharmacological activity.
Genetic resources
Picralima nitida is a common species of the African forest zone, and is not threatened by genetic erosion. However, in some areas with a high human population pressure, the species has become scarce because of its use as medicinal plant or timber.
Prospects
The specific indole alkaloids from Picralima nitida have very interesting properties, which have only partly been evaluated in tests, including some clinical trials. Extracts from different parts of Picralima nitida showed a marked activity against malaria; akuammine and alstonine were shown to be the most active alkaloids. These alkaloids may represent an entirely new antimalarial chemotype with possible advantages over existing drugs. More research is needed to confirm these findings. It has also been demonstrated that Picralima nitida has a broad activity for treating parasitic diseases, which lends credibility for its use against diarrhoea, gonorrhoea and intestinal worms. In clinical trials, the methanol extract of the stem bark exhibited impressive effectiveness against different skin diseases. More work, however, is required to develop the extract into a clinically useful antimicrobial and antifungal agent.
Akuammidine, akuammine, pseudo-akuammigine and akuammicine are opioid compounds, having significant analgesic activities. The mechanism of action and the potential for causing addiction and dependence should be investigated, as well as the toxicity.
Major 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.
• Corbett, A.D., Menzies, J.R.W., Macdonald, A., Paterson, S.J. & Duwiejua, M., 1996. The opioid activity of akuammine, akuammicine and akuammidine: alkaloids from Picralima nitida (fam. Apocynaceae). British Journal of Pharmacology 119: P334 Supplement S.
• Ezeamuzie, I.C., Ojinnaka, M.C., Uzogara, E.O. & Oji, S.E., 1994. Anti-inflammatory, antipyretic and anti-malarial activities of a West African medicinal plant - Picralima nitida. African Journal of Medicine and Medical Sciences 23(1): 85–90.
• Fakeye, T.O., Itiola, O.A. & Odelola, H.A., 2000. Evaluation of the antimicrobial property of the stem bark of Picralima nitida (Apocynaceae). Phytotherapy Research 14(5): 368–370.
• François, G., Ake Assi, L., Holenz, J. & Bringmann, G., 1996. Constituents of Picralima nitida display pronounced inhibitory activities against asexual erythrocytic forms of Plasmodium falciparum in vitro. Journal of Ethnopharmacology 54: 113–117.
• Iwu, M.M. & Klayman, D.L., 1992. Evaluation of the in vitro antimalarial activity of Picralima nitida extracts. Journal of Ethnopharmacology 36(2): 133–135.
• Menzies, J.R.W., Paterson, S.J., Duwiejua, M. & Corbett, A.D., 1998. Opioid activity of alkaloids extracted from Picralima nitida (fam. Apocynaceae). European Journal of Pharmacology 350(1): 101–108.
• Neuwinger, H.D., 1996. African ethnobotany: poisons and drugs. Chapman & Hall, London, United Kingdom. 941 pp.
• Omino, E.A., 1996. A contribution to the leaf anatomy and taxonomy of Apocynaceae in Africa. Wageningen Agricultural University Papers 96–1. Wageningen Agricultural University, Wageningen, Netherlands. 178 pp.
• Ramirez, A. & García-Ribio, S., 2003. Current progress in the chemistry and pharmacology of akuammiline alkaloids. Current Medicinal Chemistry 10: 1891–1915.
Other references
• Adjanohoun, E.J., Aboubakar, N., Dramane, K., Ebot, M.E., Ekpere, J.A., Enow-Orock, E.G., Focho, D., Gbilé, Z.O., Kamanyi, A., Kamsu, K.J., Keita, A., Mbenkum, T., Mbi, C.N., Mbiele, A.L., Mbome, I.L., Mubiru, N.K., Nancy, W.L., Nkongmeneck, B., Satabié, B., Sofowora, A., Tamze, V. & Wirmum, C.K., 1996. Contribution to ethnobotanical and floristic studies in Cameroon. CSTR/OUA, Cameroon. 641 pp.
• Aguwa, C.N., Ukwe, C.V., Inya-Agha, S.I. & Okonta, J.M., 2001. Antidiabetic effect of Picralima nitida aqueous seed extract in experimental rabbit model. Journal of Natural Remedies 1(2): 135–139.
• Ansa-Asamoah, R. & Ampofo, A.A., 1986. Analgesic effect of crude extracts of Picralima nitida seeds. African Journal of Pharmacology 1: 35–38.
• Arens, H., Borbe, H.O., Ulbrich, B. & Stoeckigt, J., 1982. Detection of pericine, a new central nervous system active indole alkaloid from Picralima nitida cell suspension culture by opiate receptor binding studies. Planta Medica 46(4): 210–214.
• Betti, J.L., 2002. Medicinal plants sold in Yaoundé markets, Cameroon. African Study Monographs 23(2): 47–64.
• 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): 1–27.
• CE-FAO, 1999. Données statistiques des produits forestiers non-ligneux du Cameroun. Rapport technique. Programme de partenariat CE-FAO (1998–2001), Rome, Italy. 36 pp.
• Duwiejua, M., Obiri, D.D., Zeitlin, I.J. & Waterman, P.G., 1995. Anti-inflammatory activity in extracts from Picralima nitida (Fam. Apocynaceae). British Journal of Pharmacology 116: P360 Supplement S.
• Duwiejua, M., Woode, E. & Obiri, D.D., 2002. Pseudo-akuammigine, an alkaloid from Picralima nitida seeds, has anti-inflammatory and analgesic actions in rats. Journal of Ethnopharmacology 81: 73–79.
• Endress, M.E., Sennblad, B., Nilsson, S., Civeyrel, L., Chase, M.W., Huysmans, S., Grafström, E. & Bremer, B., 1996. A phylogenetic analysis of Apocynaceae s.s. and some related taxa in Gentianales: a multidisciplinary approach. Opera Botanica Belgica 7: 59–102.
• Fakeye, T.O., Awe, S.O., Odelola, H.A., Ola-Davies, O.E., Itiola, O.A. & Obajuluwa, T., 2004. Evaluation of valuation of toxicity profile of an alkaloidal fraction of the stem bark of Picralima nitida (fam. Apocynaceae). Journal of Herbal Pharmacotherapy 4(3): 37–45.
• Fakeye, T.O., Itiola, O.A., George, A.O. & Odelola, H.A., 2004. Antimicrobial property of Picralima nitida stem bark extract in cream formulations. Pharmaceutical Biology 42(4–5): 274–279.
• InsideWood, undated. [Internet] http://insidewood.lib.ncsu.edu/search/. Accessed May 2007.
• Inya-Agha, S.I., 1999. The hypoglycemic properties of Picralima nitida. Nigerian Journal of Natural Products and Medicine 3: 66–67.
• Iwu, M.M., Jackson, J.E., Tally, J.D. & Klayman, D.L., 1992. Evaluation of plant extracts for antileishmanial activity using a mechanism-based radiorespirometricmicrotechnique (RAM). Planta Medica 58(5): 436–441.
• Kapadia, G.J., Angerhofer, C.K. & Ansa-Asamoah, R., 1993. Akuammine: an antimalarial indolemonoterpene alkaloid of Picralima nitida seeds. Planta Medica 59(6): 565–566.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Normand, D. & Paquis, J., 1976. Manuel d’identification des bois commerciaux. Tome 2. Afrique guinéo-congolaise. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 335 pp.
• Obiri, D.D., 1997. Studies on anti-inflammatory activity of extracts of seeds of Picralima nitida. M. Pharm. degree thesis, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. 139 pp.
• Wosu, L.O. & Ibe, C.C., 1989. Use of extracts of Picralima nitida bark in the treatment of experimental trypanosomiasis: a preliminary study. Journal of Ethnopharmacology 25(3): 263–268
Sources of illustration
• Omino, E.A., 1996. A contribution to the leaf anatomy and taxonomy of Apocynaceae in Africa. Wageningen Agricultural University Papers 96–1. Wageningen Agricultural University, Wageningen, Netherlands. 178 pp.
Author(s)
N. Nyunaï
Center for Medical Research, Institute of Medical Research and Medicinal Plants Studies, P.O. Box 3805, Yaoundé, Cameroon
N. Njifutié
Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon


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, Réduit, 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:
Nyunaï, N. & Njifutié, N., 2006. Picralima nitida (Stapf) T.Durand & H.Durand. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
Distribution Map wild


1, flowering branch; 2, leafy branch; 3, flower from above.
Redrawn and adapted by Iskak Syamsudin



trunk


slash and bark


slash and bark


leafy twig and fruit


seedlings


seeds