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Aloe vera (syn. A. barbadensis Mill., A. vulgaris Lam.) is a species of Aloe, native to northern Africa. It is a stemless or very short-stemmed succulent plant growing to 80-100 cm tall, spreading by offsets and root sprouts. The leaves are lanceolate, thick and fleshy, green to grey-green, with a serrated margin. The flowers are produced on a spike up to 90 cm tall, each flower pendulous, with a yellow tubular corolla 2-3 cm long.
Cultivation
Aloe vera is relatively easy to care for in cultivation in frost-free climates. The species requires well-drained sandy potting soil in moderate light. If planted in pot or other containers ensure sufficient drainage with drainage holes.The use of a good quality commercial potting mix to which extra perlite, granite grit, or coarse sand are added is recommended. Alternatively, pre-packaged 'cacti and succulent mixes' may also be used. Potted plants should be allowed to completely dry prior to re-watering. During winter, A. vera may become dormant, during which little moisture is required. In areas that receive frost or snow the species is best kept indoors or in heated glasshouses.
A. vera has a long history of cultivation throughout the drier tropical and subtropical regions of the world, both as an ornamental plant and for herbal medicine. For its herbal and medicinal uses, many of which are shared with related species, see Aloe.
Food preservative
Researchers at the University of Miguel Hernández in Alicante, Spain, have developed a gel based on A. vera that prolongs the conservation of fresh produce, such as fresh fruit and legumes. This gel is tasteless, colorless and odorless. This natural product is a safe and environmentally friendly alternative to synthetic preservatives such as sulfur dioxide. The study showed that grapes at 1°C coated with this gel could be preserved for 35 days against 7 days for untreated grapes. According to the researchers, this gel operates through a combination of mechanics (Serrano et al., 2006), forming a protective layer against the oxygen and moisture of the air and inhibiting, through its various antibiotic and antifungal compounds, the action of micro-organisms that cause foodborne illnesses.
Medicinal uses
A. vera has been used externally to treat various skin conditions such as cuts, burns and eczema. It is alleged that sap from Aloe vera eases pain and reduces inflammation. Evidence on the effects of A. vera sap on wound healing, however, is contradictory (Vogler and Ernst, 1999). A study performed in the 1990s showed that the healing time of a moderate to severe burn was reduced when the wound was treated on a regular basis with Aloe vera gel, compared to the healing of the wound covered in a gauze bandage (Farrar, 2005). In contrast, another study suggested wounds to which Aloe vera gel was applied were significantly slower to heal (Schmidt and Greenspoon, 1991).
A. vera's beneficial properties may be attributed to mucopolysaccharides present in the inner gel of the leaf, especially acemannan (acetylated mannans). An injectable form of acemannan manufactured and marketed by Carrington Laboratories as Acemannan Immunostimulant™ has been approved in the USA for treatment of fibrosarcoma (a type of cancer) in dogs and cats after clinical trials. It has not been approved for use by humans, and although it is not a drug its sale is controlled and it can only be obtained through a veterinary doctor.
Cosmetic companies add sap or other derivatives from A. vera to products such as makeup, moisturisers, soaps, sunscreens, shampoos and lotions, though the effectiveness of Aloe vera in these products remain unknown. A. vera gel is also alleged to be useful for dry skin conditions, especially eczema around the eyes and sensitive facial skin.
An article published in the British Journal of General Practice suggests that A. vera is effective at treating athlete's foot Template:Fact. The topical application of A. vera is not an effective preventative for radiation-induced injuries.
Whether or not it promotes wound healing is unknown, and even though there are some promising results, clinical effectiveness of oral or topical A. vera remains unclear at present.
Aloe vera juice may help some people with ulcerative colitis, an inflammatory bowel disease.
Greenleaf Aloe Vera Gel, manufactured by Brihans in India, cites their product as useful in the treatment of acne and undereye circles.
Parts that can be used
The lower leaf of the plant is used for medicinal purpose. If the lower leaf is sliced open, the gel obtained can be applied on the affected area. Leaves and seeds are the two edible parts of Aloe Vera.
Use in foods
In Japan Aloe Vera is commonly used as an ingredient in commercially available yogurt. There are also several Korean companies which produce Aloe Vera beverages.
In Pakistan, the plant has been used for centuries as a carminative and digestive aid. The dried gel is mixed with seeds of various herbs and consumed after a meal.
Tribes in the Hazara region of the North West Frontier Province have been using Aloe Vera for centuries to improve physical endurance, probably due to the high nutrient content of the gel.
People in Rajastahn state of India prepare vegetable out of Aloe Vera along with fenugreek seeds.
People in Tamil nadu, another state of India prepare a curry using Aloe Vera which is taken along with Indian bread or Rice.
In Mexico some people make smoothies out of Aloe Vera.
References
- The effect of Acemannan Immunostimulant in combination with surgery and radiation therapy on spontaneous canine and feline fibrosarcomas
- Decreased mortality of Norman murine sarcoma in mice treated with the immunomodulator, Acemannan.
- Induction of Apoptosis in a Macrophage Cell Line RAW 264.7 By Acemannan, a -(1,4)-Acetylated Mannan
- Serrano M, Valverde JM, Guillen F, Castillo S, Martinez-Romero D, Valero D. (2006). Use of Aloe vera gel coating preserves the functional properties of table grapes. J Agric Food Chem 54 (11): 3882-3886. see also.
- Plants for a Future: Aloe vera
- Flora Europaea: Aloe vera (lists only as an introduced plant, contrary to statements of European origin in some other sources)
- Flora of China: Aloe vera