Prota 11(1): Medicinal plants/Plantes mιdicinales 1
Pflanzenw. Ost-Afrikas: 140 (1895).
2n = 14
Origin and geographic distribution
Aloe secundiflora occurs in Rwanda, southern Ethiopia, Kenya and Tanzania.
The leaves of Aloe secundiflora are applied to wounds to assist healing. The leaf sap is drunk as an appetizer and anti-emetic. Diluted leaf sap is drunk as a cure for malaria, typhoid fever, diarrhoea, oedema, swollen diaphragm, nosebleed, headache, pneumonia, chest pain and as a disinfectant. The exudate is applied into the eyes, to cure conjunctivitis. The bitter exudate is applied to nipples to wean children. The basal parts of the leaves are used in the fermentation of local beer by several tribes in East Africa. The leaves are pounded and added to drinking water for preventing or treating coccidiosis and Newcastle disease in poultry. The plant is sometimes added as an ingredient to Acokanthera schimperi (A.DC.) Schweinf. or Adenium obesum (Forssk.) Roem. & Schult. for arrow poison in Kenya.
Two products from Aloe secundiflora can be used commercially in the manufacture of medicinal and cosmetic preparations. One is the gel from the centre of the leaf, and the other is the exudate from longitudinal vessels situated at the outer sides of the vascular bundles of the leaves. In Kenya only the exudate is harvested, as it can be processed easily into a solid material suitable for trading, known as bitters. Most of the material harvested in Kenya is exported. One small factory in Kenya uses Aloe in the manufacture of bathing soap and a crude medicine for abdominal pain. Large-scale Kenyan producers of cosmetic products import gel of Aloe vera (L.) Burm.f. Aloe secundiflora is planted as a garden ornamental in tropics and subtropics. In East Africa farmers sometimes plant Aloe secundiflora as a live fence.
Production and international trade
In 1986 the President of Kenya announced that all Aloe species were to be protected in Kenya, and that commercial exploitation must be from plantations and not from wild plants. Although this was not formalised into law, the CITES Licensing Office in Kenya has refused since then to give export permits for Aloe plants and Aloe products. Therefore, all international trade from Kenya is illegal and no official trade figures are available. The Kenya Aloes Working Group, inaugurated in 2004, has initiated arrangements for registration of plantations developed with propagated material, and legal trading in Aloe products.
Aloe secundiflora is one of the Aloe species in Kenya harvested illegally from the wild. It appears that there is a substantial international trade in dried exudate, but the exported product is probably a mixture of exudate from several species. Informal figures for 2003 suggest that up to 85,000 kg of solid bitters with a market value of about US$ 840,000 are exported from Kenya per year. Main importers are China and Saudi Arabia.
Distinctive constituents in Aloe leaves are phenolic compounds, notably chromone, anthraquinone or anthrone derivatives, but the chemistry varies considerably among species. Some of the compounds are found in many species, whereas others occur in only a few. The major components of the leaf exudate of Aloe secundiflora are the anthrones aloenin, aloenin B, aloin A (barbaloin) and other aloin-derivatives. The exudate also contains chromones and phenylpyrones, and the phenyl-ethylamine alkaloid N-methyltyramine. No information is available on the polysaccharides in the gel. In a field experiment, the leaf extract was found to be significantly active against fowl typhoid caused by Salmonella gallinarum and against Newcastle disease virus (NDV) in chickens.
Adulterations and substitutes
As harvesting from the wild is uncontrolled, exudates are collected indiscriminately from many Aloe spp. now in Kenya. Only the 3 species known to be poisonous are avoided. Dealers buying from the collectors have not developed any method of quality control and rely on visual assessment only.
Succulent, perennial herb, without stem or with stem up to 30 cm long, usually solitary, sometimes suckering to form small groups. Leaves about 20 in a dense rosette; stipules absent; petiole absent; blade ovate-lanceolate, 3075 cm Χ 830 cm, apex long-acuminate, margin with dark brown, sharp teeth, 36 mm long, 12 cm apart, surface smooth, dull green, often with horny margin; exudate yellow. Inflorescence consisting of racemes, 1520 cm long, lax, flowers arranged at one side; peduncle 11.5 m long, with up to 12 branches, the lower branches rebranched; bracts ovate-acute, 37 mm long, pale brown, papery. Flowers bisexual, regular, 3-merous; pedicel 510 mm long; perianth tubular, 2.53.5 cm long, inflated around the ovary, lobes 6, 1217 mm long, rose-pink to dull scarlet, paler at mouth; stamens 6, exserted; ovary superior, 3-celled, style filiform, stigma head-shaped, exserted. Fruit an oblong-ovoid capsule up to 25 mm Χ 14 mm, pale brown, dehiscing loculicidally, many-seeded. Seeds c. 8.5 mm long, blackish brown, with speckled wings.
Other botanical information
Aloe comprises about 450 species in Africa and Arabia, of which c. 315 occur in mainland Africa, c. 100 are endemic to Madagascar or the Indian Ocean islands (including the former Lomatophyllum) and c. 50 occur in Arabia. The taxonomy is complicated by the occurrence of interspecific hybrids both in the wild and in cultivation. Two varieties of Aloe secundiflora are recognized: var. secundiflora and the suckering var. sobolifera S.Carter; the latter is only known from Tanzania. Natural hybrids with several other species have been reported. Apart from Aloe secundiflora, there are several other East African species with similar growth habit and with medicinal use or use as poison. Aloe macrosiphon Baker is used medicinally and has very similar chemical properties to Aloe vera. Aloe ruspoliana Baker is poisonous to sheep and camels and is used in Somalia and Kenya to poison hyenas.
Growth and development
Seedlings take a couple of years before they are large enough for harvesting. Although Aloe secundiflora is drought tolerant it needs water to develop new leaves.
Like all Aloe species, Aloe secundiflora is well adapted to dry semi-arid conditions. It occurs in grassland and open woodland on sandy soil at 6002000 m altitude.
Propagation and planting
With the exception of the relatively rare var. sobolifera, Aloe secundiflora plants have solitary or few (up to 3) rosettes. Therefore they are usually propagated from seed. There are plans to use tissue culture techniques to produce large numbers of plants for establishing plantations.
To protect wild populations and increase production, plantations of Aloe secundiflora are being established. As establishment is just starting, there are no data yet on management techniques.
Diseases and pests
Aloe species grown in gardens in Kenya for decorative purposes are susceptible to fungal attack, scale insects and mealy bug infestation. Newly established plantations will need to be closely monitored for signs of diseases and pests.
In some areas, wild plants of Aloe secundiflora are harvested on a sustainable basis and the same plants can be used for many years. In areas where there is no established tradition of harvesting, wild plants are frequently destroyed while collecting the exudate. To harvest the exudate from Aloe secundiflora, a hole is dug in the ground and lined with a container. Cut leaves are arranged around the edge of the hole at an angle allowing the exudate to drain into the container. The exudate is transferred to bottles or jerry cans for sale to a dealer.
Harvesting of exudate takes place throughout the year, though it has been observed that the yield is higher during rainy seasons. On average one mature plant can produce 80100 ml of exudate. In some areas of Kenya the dealers obtain up to 1700 l/day from collectors.
Handling after harvest
Dealers only visually inspect the quality of the exudate. The usual reason for rejection of the exudates is that the liquid is too thin, or watery, as seen from the ease with which a small sample will soak into the ground. To concentrate the exudate it is placed in a large drum and boiled so that it becomes reddish black and very viscous. It is then transferred from the drum to sacks, in which it is left to cool and harden. After a day of cooling the material is solid and black, called bitters, and is ready for sale to a middleman, who will sell on to an exporter. Because of the illegality in Kenya the whole marketing chain is shrouded in secrecy.
Aloe secundiflora is collected indiscriminately from the wild, with no selection factors involved. The few plantations now being established are stocked with plants (probably from various species) collected in the wild. All Aloe species, except Aloe vera, are protected by CITES and all international trade of plants and products should be regulated.
So far, there has been no attempt to improve the stock of Aloe secundiflora by breeding.
Once legislation is in place and plantations are established, Aloe secundiflora will be a valuable crop for marginal areas where low rainfall makes it difficult to obtain good yields from conventional crops. The Kenya Aloes Working Group intends to look for ways of improving the processing and quality control of the product.
Carter, S., 1994. Aloaceae. In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 60 pp.
Kihara, F.I., Mathuva, J.M., Kamau, M.G. & Mathenge, G., 2003. Aloe trade in Kenya: Market Study Report. Laikipia Wildlife Forum, Nanyuki, Kenya. 64 pp. + Appendices.
Mascolo, N., Izzo, A.A., Borrelli, F., Capasso, R., Di Carlo, G., Sautebin, L. & Capasso, F., 2004. Healing powers of aloes. In: Reynolds, T. (Editor). Aloes: the genus Aloe. CRC Press, Boca Raton, Florida, United States. pp. 209238.
Newton, L.E., 2001. Aloe In: Eggli, U. (Editor). Illustrated handbook of succulent plants: Monocotyledons. Springer-Verlag, Berlin, Germany. pp. 103186.
Newton, L.E., 2004. Aloes in habitat. In: Reynolds, T. (Editor). Aloes: the genus Aloe. CRC Press, Boca Raton, Florida, United States. pp. 314.
Atiti, A.B., 2004. Encounters with Kenyan succulents. Roots; Botanic Garden Conservation International Education Review 1(1): 2324.
CITES, 2003. Review of significant trade: East African Aloes. [Internet] http://www.cites.org/ eng/com/ PC/14/E-PC14-09-02-02-A4.pdf. Accessed May 2004.
Dagne, E., Abiy Yenesew, Senait Asmellash, Sebsebe Demissew & Stephen Mavi, 1994. Anthraquinones, pre-anthraquinones and isoeleutherol in the roots of Aloe species. Phytochemistry 35(2): 401406.
Demissew Sebsebe & Gilbert, M.G., 1997. Aloaceae. In: Edwards, S., Mesfin Tadesse, Demissew Sebsebe & Hedberg, I. (Editors). Flora of Ethiopia and Eritrea. Volume 6. Hydrocharitaceae to Arecaceae. The National Herbarium, Addis Ababa University, Addis Ababa, Ethiopia and Department of Systematic Botany, Uppsala University, Uppsala, Sweden. pp. 117135.
Gachathi, F.N., 1989. Kikuyu botanical dictionary of plant names and uses. AMREF, Nairobi, Kenya. 242 pp.
Kokwaro, J.O., 1993. Medicinal plants of East Africa. 2nd Edition. Kenya Literature Bureau, Nairobi, Kenya. 401 pp.
Baerts, M. & Lehmann, J., 2005. Aloe secundiflora. [Internet]. Prelude Medicinal Plants Database. Metafro-Infosys, Royal Museum for Central Africa, Tervuren, Belgium http://www.metafro.be/prelude. Accessed September 2005.
Musila, W., Kisangau, D. & Muema, J., 2004. Conservation status and use of medicinal plants by traditional medical practitioners in Machakos District, Kenya. [Internet] http://www.ed.psu.edu/ icik/ 2004Proceedings/section3-musila-kisangau-muema-withpics.pdf Accessed August 2005.
Neuwinger, H.D., 1996. African ethnobotany: poisons and drugs. Chapman & Hall, London, United Kingdom. 941 pp.
Newton, L.E., 1994. Exploitation and conservation of aloes in Kenya. In: Seyani, J.H. & Chikuni, A.C. (Editors). Proceedings of the 13th plenary meeting of AETFAT, Zomba, Malawi. Volume 1. National Herbarium and Botanic Gardens of Malawi, Zomba, Malawi. pp. 219222.
Newton, L.E., 1995. Natural hybrids in the genus Aloe (Aloaceae) in East Africa. Journal of East African Natural History 84: 141145.
Oketch-Rabah, H.A.T., 1996. Leaf compounds in potential plantation species of Aloe in Kenya. Journal of Herbs, Spices & Medicinal Plants 4(3): 2533.
Oketch-Rabah, H., Dossaji, S.F. & Mberu, E.K., 1999. Antimalarial activity of some Kenyan medicinal plants. Pharmaceutical Biology 37(5): 329334.
Waihenya, R.K., Mtambo, M.M. & Nkwengulila, G., 2002. Evaluation of the efficacy of the crude extract of Aloe secundiflora in chickens experimentally infected with Newcastle disease virus. Journal of Ethnopharmacology 79(3): 299304.
Waihenya, R.K., Mtambo, M.M., Nkwengulila, G. & Minga, U.M., 2002. Efficacy of crude extract of Aloe secundiflora against Salmonella gallinarum in experimentally infected free-range chickens in Tanzania. Journal of Ethnopharmacology 79(3): 317323.
Waihenya, R., Kayser, O., Hagels, H., Zessin, K.H., Mtambo, M. & Nkwengulila, G., 2003. The phytochemical profile and identification of main phenolic compounds from the leaf exudate of Aloe secundiflora by high-performance liquid chromatography-mass spectroscopy. Phytochemical Analysis 14(2): 8386.
Sources of illustration
Agnew, A.D.Q. & Agnew, S., 1994. Upland Kenya wild flowers: a flora of the ferns and herbaceous flowering plants of upland Kenya. 2nd Edition. East Africa Natural History Society, Nairobi, Kenya. 374 pp.
Carter, S., 1994. Aloaceae. In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 60 pp.
Correct citation of this article:
Newton, L.E., 2006. Aloe secundiflora Engl. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes mιdicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
1, plant habit; 2, part of inflorescence; 3, leaf margin.
Redrawn and adapted by Achmad Satiri Nurhaman