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Senna singueana (Delile) Lock

Protologue
Kew Bull. 43(2): 340 (1988).
Family
Caesalpiniaceae (Leguminosae - Caesalpinioideae)
Synonyms
Cassia singueana Delile (1826), Cassia goratensis Fresen. (1839).
Vernacular names
Winter cassia, sticky pod, scrambled egg (En). Pintcheira do mato (Po). Mbaraka, mkundekunde (Sw).
Origin and geographic distribution
Senna singueana occurs throughout mainland tropical Africa and is probably only absent from Gabon, Djibouti and Somalia. In the Indian Ocean islands it is only on record for the Comoros.
Uses
Senna singueana has many medicinal uses throughout Africa. A hot water infusion of the leaves is drunk and the warm leaves are applied as a compress to treat fever. The leaf sap is drunk to cure malaria. The leaves in decoction or infusion or as dried powder are applied to wounds caused by leprosy and syphilis. An infusion of the leaves is applied as eye drops to cure conjunctivitis. Extracts of the stem bark are taken to cure stomach complaints. Like the leaves, the stem bark is used to treat skin disorders and malaria. An infusion of the flowers is used as an eye lotion. The fruit pulp soaked in water and cooked with a staple food is eaten by lactating women as it is considered lactogenic. The roots are used to treat venereal diseases, stomach complaints and as a purgative. The roots are also used to cure impotence caused by diabetes. The ash of burnt roots is eaten mixed with porridge to cure abdominal pain. Leaves, stem and root bark are used as an anthelminthic and to treat bilharzia.
As an ornamental Senna singueana is spectacular, with flowers appearing before the onset of the rains, but it is only used for this purpose in its native range. The leaves are eaten as a cooked vegetable in Malawi and Tanzania, but elsewhere they are considered poisonous. The stem bark is used as a dye for textile in Ethiopia and Zambia and for tanning hides in large parts of East Africa. The fruits are used in Sudan for tanning skins. Bananas are wrapped in the leaves to speed ripening. The foliage is browsed by livestock. The wood is useful as firewood, and also for hut building, small furniture and carvings. The root fibres are used in hairpieces.
Properties
From the roots 4 tetrahydroanthracene derivatives, singueanol-I and -II, torosachrysone and germichrysone, were isolated as well as the pentacyclic triterpene lupeol and steroids (campesterol, β-sitosterol and stigmasterol). The anthracene derivatives showed significant activity against several gram-positive bacteria in vitro and showed antispasmodic activity in isolated guinea pig colon. Extracts of the root bark have also shown significant analgesic, antipyretic, anthelminthic and antiplasmodial activity. The leaves have anthelminthic and antiviral properties, but no significant antibacterial activity. The stem bark contains tannins and is astringent. The leaves contain tannins, but a recent study indicated that digestibility is quite good and not constrained by the presence of tannins. In grazing land with ample Senna singueana shrubs the intake by cattle appeared to be very low, so another anti-feedant factor is likely involved. The leaves contain the flavonoid leucopelargonidin, which has dyeing properties. The wood is pale brown.
Botany
Deciduous shrub or small tree up to 15 m tall. Leaves arranged spirally, paripinnately compound with 5–12 pairs of leaflets; stipules linear-lanceolate, acuminate, soon falling; leaflets elliptical, oblong-elliptical to obovate-elliptical, 2.5–6.5 cm Χ 1.5–3 cm, unequal at base, mostly rounded or notched at apex, glabrous to hairy on both sides. Inflorescence a stalked, terminal raceme up to 15 cm long, 6–many-flowered; bracts 9–27 mm long. Flowers bisexual or female, zygomorphic, 5-merous; sepals oblong-obovate, up to 14 mm long; petals unequal, oblong to obovate, 1.5–3 cm long, yellow; stamens 10, the 3 lower ones largest and fertile, 7 sterile; ovary superior, c. 2 cm long, stipitate, down-curved. Fruit a cylindrical to slightly compressed, straight or slightly twisted, oblong pod 5–25 cm Χ 0.5–1 cm, slightly constricted between the seeds, indehiscent, apex rounded and shortly pointed, 8–25-seeded. Seeds compressed, round, 5–6 mm in diameter, with a small areole on each face.
Senna singueana often flowers when still leafless. It is susceptible to fire, although the thick bark gives some protection. It is often associated with insects like ants and carpenter bees, and the sticky pods are frequently visited by flies. It does not produce root nodules, hence does not fix nitrogen.
Until the early 1980s, Cassia was considered a very large genus of about 550 species, but was then split into 3 genera: Cassia s.s. with about 30 species, Chamaecrista with about 250 species and Senna with about 270 species. Senna is very similar to Cassia, but is distinguished from it by the possession of 3 adaxial stamens which are short and straight, and the pedicels which have no bracteoles.
Ecology
Senna singueana occurs in thickets, woodland, savanna and dry evergreen forest, often on termite mounds, from sea-level up to 2250 m altitude. It is found in areas with an annual rainfall of 500–1000 mm.
Management
Senna singueana is propagated by seedlings, including wildlings, and is quick growing. Dry seed stored in an airtight container remains viable for at least 3 years. Seed germinates in about 9 days with an average germination rate of 78%.
If a tree with a straight stem is required, protection against browsing animals is needed. Trees can be coppiced.
Genetic resources and breeding
Senna singueana is widespread and common in most of its range. In Namibia, where the roots are harvested for medicinal use, it has become rare and needs conservation.
Prospects
Although Senna singueana has numerous medicinal uses, research into its pharmacology has been scarce and restricted to the root bark. Because of their many medicinal uses, research into the properties of the leaves is warranted. The leaves are a more sustainable source of medicine than root or stem bark. The morphological variation in the species in connection to its uses and variation in phytochemistry needs further research.
Major references
• Adzu, B., Abbah, J., Vongtau, H. & Gamaniel, K., 2003. Studies on the use of Cassia singueana in malaria ethnopharmacy. Journal of Ethnopharmacology 88(2–3): 261–267.
• Brenan, J.P.M., 1967. Leguminosae, subfamily Caesalpinioideae. In: Milne-Redhead, E. & Polhill, R.M. (Editors). Flora of Tropical East Africa. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. 230 pp.
• Burkill, H.M., 1995. The useful plants of West Tropical Africa. 2nd Edition. Volume 3, Families J–L. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 857 pp.
• Endo, M. & Naoki, H., 1980. Antimicrobial and antispasmodic tetrahydroanthracenes from Cassia singueana. Tetrahedron 36(17): 2449–2452.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
Other references
• Bein, E., Habte, B., Jaber, A., Birnie, A. & Tengnδs, B., 1996. Useful trees and shrubs in Eritrea: identification, propagation and management for agricultural and pastoral communities. Technical Handbook No 12. Regional Soil Conservation Unit, Nairobi, Kenya. 422 pp.
• Coates Palgrave, K., 1983. Trees of southern Africa. 2nd Edition. Struik Publishers, Cape Town, South Africa. 959 pp.
• World Agroforestry Centre, undated. Agroforestree Database. [Internet] World Agroforestry Centre (ICRAF), Nairobi, Kenya. http://www.worldagroforestry.org/ Sites/TreeDBS/ aft.asp. Accessed October 2006.
• Kehlet, A.B. & Hansen, H.H., 2004. Digestibility of selected Tanzanian browse suspected of containing tannins. Paper presented on the 2004 annual meeting of the Tanzanian Society for Animal Production (TSAP) in Moshi, Tanzania. [Internet] http://www.husdyr.kvl.dk/ htm/hhh/confpubl/ annefinalTSAP.pdf. Accessed October 2006.
• Kokwaro, J.O., 1993. Medicinal plants of East Africa. 2nd Edition. Kenya Literature Bureau, Nairobi, Kenya. 401 pp.
• Kudi, A.C. & Myint, S.H., 1999. Antiviral activity of some Nigerian medicinal plant extracts. Journal of Ethnopharmacology 68: 289–294.
• Moshi, M.J. & Mbwambo, Z.H., 2002. Experience of Tanzanian traditional healers in the management of non-insulin dependent diabetes mellitus. Pharmaceutical Biology 40(7): 552–560.
• Mutasa, S.L., Khan, M.R. & Jewere, K., 1990. 7-Methylphyscion and cassiamin A from the root bark of Cassia singueana. Planta Medica 56: 244–245.
• SEPASAL, 2006. Senna singueana. [Internet] Survey of Economic Plants for Arid and Semi-Arid Lands (SEPASAL) database. Royal Botanic Gardens, Kew, Richmond, United Kingdom. http://www.kew.org/ ceb/sepasal/. Accessed October 2006.
• Williamson, J., 1955. Useful plants of Nyasaland. The Government Printer, Zomba, Nyasaland. 168 pp.
Author(s)
• V. Kawanga
Zambian Branch, Commonwealth Forestry Association, Private Bag RW 359X, Ridgeway, 15102 Lusaka, Zambia
• C.H. Bosch
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, Rιduit, 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:
Kawanga, V. & Bosch, C.H., 2007. Senna singueana (Delile) Lock. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes mιdicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
bark
obtained from
B. Wursten


inflorescence
obtained from
B. Wursten


infructescence
obtained from
B. Wursten