Pentadiplandra brazzeana Baill. Protologue Bull. Mens. Soc. Linn. Paris 1: 611 (1886). Family Pentadiplandraceae Vernacular names l’Oubli (Fr). Origin and geographic distribution Pentadiplandra brazzeana occurs from Nigeria east to the Central African Republic and south to DR Congo and Angola. Uses The roots taste like horseradish and are used throughout Central Africa against several problems related to giving birth. The root bark is one of more than 20 constituents of the yellow, slimy ‘nkui’ sauce made by the Bamileke people of Cameroon; this sauce is given to mothers who have just given birth, to stimulate milk production. Among the Mezime people of Cameroon a root decoction is given orally or applied as an enema to facilitate the expulsion of the placenta; it also helps in reducing pain caused by hernia. In the Central African Republic a tuber decoction is said to prevent haemorrhages after parturition. The fresh root is pulped, or the dry root pounded and mixed with palm oil, to make an ointment for topical application to prevent infections of the navel in newborn babies. Because the plant is vesicant, the duration of treatment must be limited to avoid blistering. The crushed root or root bark is applied or an infusion drunk to soothe chest pain, toothache, lumbago, rheumatism and haemorrhoids. Powder of dried root bark is applied to scarifications to treat intercostal and abdominal pains. In Nigeria the crushed root is used to treat several skin infections and in south-western Cameroon a leaf decoction is used to wash the skin against scabies. In Cameroon and DR Congo the macerated roots, alone or mixed with other ingredients, are taken orally or applied as an enema against malaria. In Cameroon the Mezime people take a decoction of the root bark as an aphrodisiac. In the Central African Republic Capsicum pepper is added to macerated roots to prepare a drink that soothes cough. In Congo pulped roots are applied externally against itch and as an antiseptic, and to treat wounds, sores, ulcers and furuncles. A decoction of the bark mixed with bark and roots of other plants is taken against stiffness or weakness of the limbs and back. Roots and tubers are also commonly used in the treatment of intestinal problems such as dysentery, colic, urethritis, gonorrhoea and other uro-genital infections. The Monzombo people in Cameroon drink a decoction of the tuber, as well as the juice from macerated roots, mixed with pounded leaves as an anthelmintic. The roots of Pentadiplandra brazzeana also have laxative, purgative and cathartic properties, and are applied to the abdomen to treat oedema. A root decoction is taken to treat pneumonia and serious bronchitis, but administration to pregnant women is avoided owing to risk of miscarriage. It may even be used to induce abortion. Together with leaves of Kalanchoe crenata (Andrews) Haw., a root preparation is used as nose drops to stop epileptic crises. The roots smell of aspirin and are hung over the doorway or are placed inside the roof to keep away snakes. The red pulp of the fruits is eaten as a snack, or sometimes used to sweeten maize porridge. The protein brazzein, originally extracted from the fruit pulp, is being developed into a low-calorie sweetener for the food industry. The powdered root bark is said to be an ingredient of the cheap but dangerous ‘African whiskey in sachets’. The fruit is used as fish poison. The root is reportedly occasionally eaten as a vegetable. Production and international trade Commercial interest in brazzein is strong. The technology to extract the protein from the fruit pulp as well as technologies to produce brazzein by transferring the gene coding for brazzein into other organisms have been patented, without the intention of benefit sharing. The roots of Pentadiplandra brazzeana are sold for medicinal purposes in local markets. In 2006 pieces of root of c. 15 cm long were sold in the main markets of DR Congo for US$ 0.22–0.45. Dried roots are also sold via internet. A company from Cameroon sells a syrup of the root in the Congo Basin. Properties An extremely sweet crude protein, named pentadin, was isolated from the fruits; in the 1990s the purified protein was isolated and called brazzein. Its temporal profile closely resembles that of sucrose, but develops somewhat more slowly and lasts longer. It is very thermo-stable and its sweetness profile does not diminish after incubation at 100°C for 4 hours. It is also stable over a wide pH-range and is the most water-soluble protein sweetener discovered so far. Brazzein is reported to be between 500 and 2000 times sweeter than sucrose depending on the method of measuring. However, in early 2008 brazzein had not yet been granted GRAS (generally recognized as safe) status in the United States nor has been granted permission for use in foods in the European Union. The gene encoding for brazzein has been transferred to the bacteria Escherichia coli and Lactococcus lactis and to maize. Bacterial production systems for brazzein have been developed. Mutants and sections of brazzein have been discovered with sweet-taste properties superior to those of the natural protein. Phytochemical analyses of the root have led to the isolation of urea derivatives including sulphur-containing compounds. The carbamates (thiouretanes) methyl N-benzylthiocarbamate, methyl N-methoxybenzylthiocarbamate and ethyl N-methoxybenzylthiocarbamate have shown antibacterial properties in vitro against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa, and against the yeast Candida albicans. Other compounds isolated include isopropyl N-methoxybenzylthiocarbamate, dibenzylurea, dibenzylthiourea and methylated derivatives. The root is also rich in glucosinolates and is believed to contribute to the revitalizing of collagen and to restore skin tonicity. Crude extracts of tubers have revealed moderately strong antiplasmodial activity in vitro, but were not as effective as chloroquine. An aqueous extract of the root given to rats increased the weight of their testes and prostate and also their testosterone levels. Adulterations and substitutes If brazzein or any of its derivatives are admitted as a sweetener in the food industry, they will compete with other protein and non-protein sweeteners and with sugars. Description Monoecious shrub up to 5 m tall or liana up to 20 m long; root system a branched complex of bulging roots in shrubs to a large, fleshy tuber in lianas, branches glabrous. Leaves alternate, simple and entire; stipules absent; petiole 0.5–1 cm long; blade elliptical to oblanceolate, 5–15 cm × 1.5–5 cm, base cuneate, apex acuminate, glabrous, upper surface dull or shining dark green, lower surface dull dark green, pinnately veined with 5–11 pairs of lateral veins. Inflorescence an axillary or terminal raceme; peduncle up to 16 cm long. Flowers unisexual or bisexual, regular, 5-merous; pedicel 1–2 cm long; sepals free, elliptical to lanceolate, 0.5–1 cm long, green with violet margin; petals free, lanceolate to oblanceolate, 2–2.5 cm long, base widened and with conspicuous scale, apex acute, white to yellowish; androgynophore present, stout; stamens 10–13, free, filaments c. 6 mm long, thin, in female flowers rudimentary; ovary superior, 4–5-celled, style short, with 5-lobed stigma, in male flowers ovary rudimentary. Fruit a globose berry 3.5–5 cm in diameter, red or mottled grey, pulp pink, many-seeded. Seeds kidney-shaped. Other botanical information Pentadiplandra comprises a single species, and is the only genus in the family Pentadiplandraceae. Most recent analyses of floral development and anatomy conclude that Pentadiplandra represents a relict genus in a separate family at the evolutionary base of the Brassicales, with a strong affinity with the American Tovaria (Tovariaceae). It is also quite distinct on the basis of its chemotaxonomy. Growth and development When Pentadiplandra brazzeana grows as a shrub it has an extended and ramified root system; when it grows as a liana, it has a single, fleshy tuber. Flowering starts in January and continues for several months; fruit production is low and spread out until September. Shrubby plants seem to have a shorter but more condensed fruiting season, with a peak in June–July. Unconsumed fruits rot on the plant, without falling. They serve as temporary nesting sites to arboreal ants. Ecology Pentadiplandra brazzeana is common in upland primary forest dominated by Scorodophleus zenkeri Harms, and also commonly occurs on river banks and in secondary forest. In Cameroon, the plant is mainly found in forest edges bordering savanna. It is nowhere gregarious. Propagation and planting Seed dispersal is facilitated by the contrast between the extreme sweetness of the pulp of the fruit and the unpleasant bitter taste of seeds, provoking consumers to spit out the seeds. In natural habitats, squirrels, monkeys and apes contribute to the distribution of the seed; in the vicinity of human habitation, distribution by children into secondary habitats is common. Natural vegetative reproduction from portions of tubers seems unlikely as tubers and roots are buried too deeply, but it is incidentally encouraged by the harvesting of the roots and tubers for medicinal purposes. Harvesting Tubers, roots, leaves and fruits are gathered from the wild. It is likely that the collection of the roots and tubers is often destructive for the plant. Handling after harvest The sweet layer of pulp surrounding seeds is sucked fresh. The roots and tubers are dried before commercialization, but are locally used fresh immediately after collection. Genetic resources Pentadiplandra brazzeana is widespread and common, also in secondary forest. Although harvesting for medicinal purposes is often destructive, there are no indications that the species is under threat of genetic erosion. No collections of germplasm, e.g. to conserve the variation in brazzein content or composition, are known to exist. Prospects Prospects of sweet protein production have completely overshadowed the many medicinal uses of the roots and tubers of Pentadiplandra brazzeana, which indicate that the pharmacological properties should be further explored. Lastly, the patents have problematic implications since they ignore any possible benefit sharing with the West and Central African peoples who have been using the fruits for their sweetness for centuries. Major references • 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. • Hladik, C.-M. & Hladik, A., 1988. Sucres et ‘faux sucres’ de la forêt équatoriale: évolution et perception des produits sucrés par les populations forestières d’Afrique. Journal d’Agriculture Traditionnelle et de Botanique Appliquée 35: 51–66. • Keay, R.W.J., 1958. Pentadiplandraceae. In: Keay, R.W.J. (Editor). Flora of West Tropical Africa. Volume 1, part 2. 2nd Edition. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. pp. 649–651. • Ming, D. & Hellekant, G., 1994. Brazzein, a new high-potency thermostable sweet protein from Pentadiplandra brazzeana. FEBS Letters 355: 106–108. • Ming, D., Hellekant, G. & Zhong, H., 1996. Characterization and chemical modification of brazzein, a high potency thermostable sweet protein from Pentadiplandra brazzeana. Acta Botanica Yunnanica 18: 123–133. • Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp. • Ronse de Craene, L.P., 2002. Floral development and anatomy of Pentadiplandra (Pentadiplandraceae): a key genus in the identification of floral morphological trends in the core Brassicales. Canadian Journal of Botany 80: 443–459. • Tsopmo, A., Ngnokam, D., Ngamga, D., Ayafor, J.F. & Sterner, O., 1999. Urea derivatives from Pentadiplandra brazzeana. Journal of Natural Products 62: 1435–1436. • van der Wel, H., Larson, G., Hladik, A., Hladik, C.-M., Hellekant, G. & Glaser, D., 1988. Isolation and characterization of pentadin, the sweet principle of Pentadiplandra brazzeana Baillon. Chemical Senses 14(1): 75–79. • Villiers, J.-F., 1973. Pentadiplandraceae. Flore du Cameroun. Volume 15. Muséum National d’Histoire Naturelle, Paris, France. pp. 163–167. Other references • Assadi-Porter, F.M., Abildgaard, F., Blad, H., Cornilescu, C.C. & Markley, J.L., 2005. Brazzein, a small, sweet protein: effects of mutations on its structure, dynamics and functional properties. Chemical Senses 30 (supplement 1): i90–i91. • Assadi-Porter, F.M., Aceti, D.J., Cheng, H. & Markley, J.L., 2000. Efficient production of recombinant brazzein, a small, heat-stable, sweet-tasting protein of plant origin. Archives of Biochemistry and Biophysics 376(2): 252–258. • Assadi-Porter, F.M., Aceti, D.J. & Markley, J.L., 2000. Sweetness determinant sites of brazzein, a small, heat-stable, sweet-tasting protein. Archives of Biochemistry and Biophysics 376(2): 259–265. • Caldwell, J.E., Abildgaard, F., Dzakula, Z., Ming, D., Hellekant, G. & Markley, J.L., 1998. Solution structure of the thermostable sweet-tasting protein brazzein. Nature Structural Biology 5: 427–431. • El Migirab, S., Berger, Y. & Jabot, J., 1977. Isothiocyanates, thiourées et thiocarbanates isolés de Pentadiplandra brazzeana. Phytochemistry 16: 1719–1721. • Eyog Matig, O., Ndoye, O., Kengue, J. & Awono, A. (Editors), 2006. Les fruitiers forestiers comestibles du Cameroun. IPGRI Regional Office for West and Central Africa, Cotonou, Benin. 204 pp. • Izawa, H., Ota, M., Kohmura, M. & Ariyoshi, Y., 1996. Synthesis and characterization of the sweet protein brazzein. Biopolymers 39(1): 95–101. • Jin, Z., Danilova, V., Assadi-Porter, F.M., Markley, J.L. & Hellekant, G., 2003. Monkey electrophysiological and human psychophysical responses to mutants of the sweet protein brazzein: delineating brazzein sweetness. Chemical Senses 28: 491–498. • Kamtchouing, P., Mbongue, G.Y., Dimo, T. & Boukeng-Jatsa, H., 2002. Evaluation of androgenic activity of Zingiber officinale and Pentadiplandra brazzeana in male rats. Asian Journal of Andrology 4: 299–301. • Latham, P., 2004. Useful plants of Bas-Congo province, Democratic Republic of the Congo. DFID, London, United Kingdom. 320 pp. • Ngamga, D., 2005. Antimalarial secondary metabolites from some Cameroonian medicinal plants. African Journal of Traditional, Complementary and Alternative Medicines 2(2): 177–205. • Tancredi, T., Pastore, A., Salvadori, S., Esposito, V. & Temussi, P.A., 2004. Interaction of sweet proteins with their receptor. European Journal of Biochemistry 271: 2231–2240. • Temussi, P.A., 2002. Why are sweet proteins sweet? Interaction of brazzein, monellin and thaumatin with the T1R2-T1R3 receptor. FEBS Letters 526: 1–4. • Walters, D.E. & Hellekant, G., 2002. Interactions of the sweet protein brazzein with the sweet taste receptor. Journal of Agricultural and Food Chemistry 54: 10129–10133. Sources of illustration • Villiers, J.-F., 1973. Pentadiplandraceae. Flore du Cameroun. Volume 15. Muséum National d’Histoire Naturelle, Paris, France. pp. 163–167. Author(s) • E. Dounias Centre d’Ecologie Fonctionnelle et Evolutive, Center for Evolutionary and Functional Ecology (CEFE-CNRS), 1919, route de Mende, 34293 Montpellier cedex 5, France 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