Tanzanian Aloe

Aloe macrosiphon

Physical Characteristics

Aloe macrosiphon is an evergreen Perennial growing to 0.5 m (1ft 8in) by 0.5 m (1ft 8in) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 10. Suitable for: light (sandy) and medium (loamy) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers dry soil and can tolerate drought.

Distribution

East tropical Africa - Uganda, Kenya, Rwanda, Burundi, Tanzania.

Habitats

Edible Uses

None Known

Medicinal Uses

Antiasthmatic Antihaemorrhoidal Antirheumatic Antispasmodic Bitter Digestive Dysentery Kidney Kidney Laxative Purgative Refrigerant Skin Vermifuge The distinctive constituents in Aloe leaves are phenolic compounds, including chromone, anthraquinone or anthrone derivatives. Some of the compounds are found in many species, whereas others occur in only a few[ 299 ]. This species has very similar properties to Aloe vera[ 299 ]. The uses of Aloe vera are as follows:- The clear gel contained within the leaf makes an excellent treatment for wounds, burns and a host of other skin disorders, placing a protective coat over the affected area, speeding up the rate of healing and reducing the risk of infection. The gel is also applied externally to cure haemorrhoids[ 254 , 299 , K ]. These actions are in part due to the presence of aloectin B, which stimulates the immune system[ 254 ]. To obtain this gel, the leaves can be cut in half along their length and the inner pulp rubbed over the affected area of skin[ K ]. This has an immediate soothing effect on all sorts of burns and other skin problems[ K ]. The use of the gel has been approved in the United States for the treatment of leukaemia in cats, of fibrosarcoma in dogs, for wound healing in humans and to prevent dry socket in humans[ 299 ]. The peeled leaves are eaten to relieve sore throat and coughs and as a mild laxative. As a food supplement, the leaf gel is said to facilitate digestion, and to improve blood and lymphatic circulation, as well as kidney, liver and gall bladder functions[ 299 ]. There are claims of beneficial activity of Aloe vera products in cases of AIDS, arthritis, or other chronic and debilitating conditions. However, these claims have not been substantiated by scientific studies. There is also no evidence that topical Aloe vera gel is effective in preventing or minimizing radiation-induced skin reactions in cancer patients. In large amounts, the gel has anti-irritant properties[ 299 ]. A bitter substance is obtained from the yellow sap at the base of the leaf. Known as 'bitter aloes', it contains anthraquinones which are a useful digestive stimulant and a strong laxative[ 254 ]. It also has vermicidal properties[ 299 ]. It is taken internally in the treatment of chronic constipation, poor appetite, digestive problems etc[ 238 ]. Mixed with other ingredients to mask its bitter taste, it is taken against asthma and to treat coughs. Similar mixtures are taken to cure dysentery, kidney problems or against dyspepsia[ 299 ]. It should be administered preferably in combination with an antispasmodic to moderate its griping action[ 299 ]. It is applied externally as a refrigerant to treat acne or cuts[ 299 ]. 'Cura'ao aloe' should contain at least 28% hydroxy-anthraquinone derivatives; it is almost entirely soluble in 60% alcohol and for more than 70% in water. It should not contain more than 12% moisture and 3% ash[ 299 ]. The plant is strongly purgative so great care should be taken over the dosage[ 238 ]. Anthraquinone-based laxatives, such as bitter aloes, should not be used longer than 8 - 10 days, nor by children younger than 12 years. Contra-indications include pregnancy, breastfeeding, intestinal inflammations and haemorrhoids[ 238 , 243 , 299 ]. When plants are grown in pots the anthraquinone content is greatly reduced[ 254 ].

Known Hazards

The sap of Aloe species contains anthraquinones. These compounds have several beneficial medicinal actions, particularly as a laxative, and many species of Aloe are thus employed in traditional medicine. Whilst safe in small doses and for short periods of time, anthraquinones do have potential problems if used in excess. These include congestion and irritation of the pelvic organs[ 299 ]. Long term use of anthraquinone laxatives may also play a role in development of colorectal cancer as they have genotoxic potential, and tumorigenic potential[ 299 ].