ALOE ARBORESCENS GENERAL DESCRIPTION Scientific name with author Aloe arborescens Mill. Plant photo – live plant Synonyms A. arborescens Mill. var. frutescens (Salm Dyck) Link Family Asphodelaceae Vernacular/ traditional/ regional names Kransaalwyn (Afrikaans); krantz aloe (English); ikalene (Xhosa); inhlaba encane, inkalane encane, unhlabana (Zulu) Botanical description Aloe arborescens is a succulent leaved, perennial shrub of up to 2m high. Branched stems bear rosettes of narrow down-curved leaves that have soft marginal teeth. Flowers are bright red to orange and occur in conical, unbranched clusters. Reference Reynolds, G.W. (1950). The Aloes of South Africa. The Trustees of the Aloes of South Africa Book Fund, Johannesburg. Geographical distribution A. arborescens is distributed mainly over the eastern, summer rainfall areas of the country, occurring from the Cape Peninsula along the eastern coast, through KwaZulu-Natal, Mpumalanga and Limpopo province and further north into Mozambique, Zimbabwe and Malawi. References Reynolds, G.W. (1950). The Aloes of South Africa. The Trustees of the Aloes of South Africa Book Fund, Johannesburg. South African National Biodiversity Institute. (2004). Aloe arborescens Mill. http://www.plantzafrica.com/plantab/aloearbor.htm Distribution map ETHNOBOTANICAL INFORMATION Medicinal uses Leaf sap is mainly used to treat burns, wounds and a variety of skin ailments such as eczema, bruises and abrasions. The Zulu people use the leaves of this plant, dried and pounded into a powder, as a protection against storms. Decoctions of the leaves are also used in childbirth and in treating sick calves. In the Transkei cold water leaf infusions are used for stomach ache and given to chickens to prevent them from getting sick. Leaves have purgative properties. References Grace, O.M., Simmonds, M.S.J., Smith, G.F. and van Wyk, A.E. (2008). Therapeutic uses of Aloe L. (Asphodelaceae) in southern Africa. Journal of Ethnopharmacology, 119(3): 604-614. South African National Biodiversity Institute. (2004). Aloe arborescens Mill. http://www.plantzafrica.com/plantab/aloearbor.htm Van Wyk, B.-E. and Gericke, N. (2007). People’s plants: a guide to useful plants of southern Africa. Briza, Pretoria. Watt, J.M. and Breyer-Brandwijk, M.G. (1962). The medicinal and poisonous plants of southern and eastern Africa. 2nd ed. Livingstone, London. QUALITY STANDARDS Macroscopial A multiheaded shrub up to 2m high with striking grey green leaves arranged in attractive rosettes. The leaf margins are armed with conspicuous pale teeth. The large colourful flower spikes are borne in profusion during the cold winter months (May-July). Deep orange is the most common colour. The inflorescence is usually unbranched, with two to several arising from a single rosette. Reference South African National Biodiversity Institute. (2004). Aloe arborescens Mill. http://www.plantzafrica.com/plantab/aloearbor.htm Microscopial CHEMICAL CONSTITUENTS Chemical constituents – compounds diagrams Chemical constituents – compounds description A.arborescens gel contains glycoproteins and lectins, such as aloctin A and aloctin B. Compounds isolated from the leaves contain aloenin, aloein, Mg lactate and aloe emodin. Also present are β-polysaccharides, the well known anthraquinone and chromones such as aloesin, aloesone and aloe resins A and C. Aloin content increases with age and is highest in summer, lowest in winter. Anthraquinone content is highest before blooming and lowest at full bloom. Reference Reynolds, T. and Dweck, A.C. (1999). Aloe vera leaf gel: a review update. Journal of Ethnopharmacology, 68 (1-3): 3-37. Chemical constituents – organoleptic properties Chemical constituents – TLC / HPLC / GC Chemical constituents – NIR Spectroscopy image Large, colourful, bright red or deep orange flower spikes are borne in profusion during the winter months. Striking grey green leaves are arranged in attractive rosettes. The leaf margins are armed with conspicuous soft, pale teeth. Chemical constituents – NIR Purity tests / Requirements TLC, HPLC and GC are used. A national standard for South African aloe raw materials provides methods to determine the quality of aloe gel. Assay Not yet available. Plant part used Fresh leaves and fresh leaf juice are used. Processed leaf juice and gel are also used. Plant part used photograph Dosage forms Traditionally decoctions of the leaves and cold water leaf infusions are used. Pharmacology/ bioactivity Leaf extracts have shown significant wound healing, anti-bacterial, anti-ulcer, anti-inflammatory, anticarcinogenic, hypoglycaemic and also alopoeic activity. Wound healing effects are mainly ascribed to the anti-inflammatory activity of glycoproteins and Aloesin in fresh or processed leaf gel. Aloesin also inhibits melanin formation in the skin, resulting in skin-lightening effects. Immunomodulatory properties have been ascribed to leaf gel polysaccharides, especially the acetylated mannans. The purgative properties of Aloesin are well known. References Jia, Y., Zhao, G. and Jia, J. (2008). Preliminary evaluation: The effects of Aloe ferox Miller and Aloe arborescens Miller on wound healing. Journal of Ethnopharmacology, 120(2): 181-189. Viljoen, A.M. (2000). A chemotaxonomic study of phenolic leaf compounds in the genus Aloe. Ph.D. thesis, University of Johannesburg, South Africa. Contraindications Adverse reactions Arabinose is a potential toxin. Snuff made from Aloes has been associated with a high rate of cancer of the nasal sinuses. Laxative preparations containing Aloe species may cause nephritis, diarrhoea and gastritis and should be avoided by pregnant women. Cases of abortion have been reported following medicinal usage. Reference Watt, J.M. and Breyer-Brandwijk, M.G. (1962). The medicinal and poisonous plants of southern and eastern Africa. 2nd ed. Livingstone, London. Precautions Laxative preparations containing Aloe species should be avoided by pregnant women. Dosage and preparation Leaf decoctions are used in childbirth. Cold water leaf infusions are used for stomach ailments. Fresh leaf juice or gel is applied topically or used as tonic drinks. Leaf juice or gel powder is obtained by freezedrying or spray-drying the leaves. Pounded leaf infusions are used as sprinkling charms against storms. Reference Watt, J.M. and Breyer-Brandwijk, M.G. (1962). The medicinal and poisonous plants of southern and eastern Africa. 2nd ed. Livingstone, London. Source References Hutchings, A., Scott, A.H., Lewis, G. and Cunningham, A.B. (1996). Zulu Medicinal Plants: an inventory. Natal University Press, Pietermaritzburg. Van Wyk, B.-E., van Oudtshoorn, B. and Gericke, N. (2009). Medicinal plants of South Africa. 2nd ed. Briza, Pretoria.
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