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 Aloe succotrina
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Aloe (also written Aloë) is any member of the flowering plant genus Aloe, comprising about 400 species of succulent, perennial plants, most of which have a rosette of serrated leaves at the base but no or little stem. The genus is native to Africa and is common in South Africa's Cape Province and the mountains of tropical Africa, and neighboring areas such as Madagascar, the Arabian peninsula, and the islands off Africa. Today, it is widely grown in warmer climates globally and indoors.
used as ornamenals.. Some used medicinally, including Aloe vera and Aloe chinensis
Aloe vera (true aloe) most popular in terms of medicinal and cosmetic use. . examples
Description
Most aloes have a rosette of large, thick, fleshy leaves. The leaves are often lance-shaped with a sharp apex and a spiny margin. Aloe flowers are tubular, frequently yellow, orange, or red and are borne on densely clustered, simple or branched leafless stems.
Many species of aloe are seemingly stemless, with the rosette growing directly at ground level. Other varieties may have a branched or unbranched stem from which the fleshy leaves spring. They vary in color from grey to bright green and are sometimes striped or mottled.
Taxonomy
The APG II system (2003) placed the genus Aloe in the family Asphodelaceae. In the past, it has also been assigned to the lily family (Liliaceae), or the family Aloaceae.
Members of the closely allied genera Gasteria, Haworthia, and Kniphofia, which have a similar mode of growth, are also popularly known as aloes.
There are around 400 species in the genus Aloe. Among these species are:
- Aloe arborescens - Aloe Arborescens Miller, used in healthcare
- Aloe aristata - Torch Plant, Lace Aloe
- Aloe dichotoma - quiver tree or kokerboom
- Aloe ngobitensis
- Aloe variegata - Partridge-breasted Aloe, Tiger Aloe
- Aloe vera Barbados Aloe, Common Aloe, Yellow Aloe, Medicinal Aloe. This is the variety used medicinally.
- Aloe wildii
Note that the plant sometimes called "American aloe" (Agave americana), belongs to Agavaceae, a different family. Some consider the aloes and agaves to justifiably be placed in the same family.
Chemical properties of Aloin
Aloins are soluble and easily extracted by water. Aloes is the expressed juice of the leaves of the plant. When the leaves are cut, the juice that flows out is collected and evaporated. After the juice has been removed, the leaves are sometimes boiled, to yield an inferior kind of aloes. According to W. A. Shenstone, two classes of Aloins are to be recognized: (1) nataloins, which yield picric and oxalic acids with nitric acid, and do not give a red coloration with nitric acid; and (2) barbaloins, which yield aloetic acid (C7H2N3O5), chrysammic acid (C7H2N2O6), picric and oxalic acids with nitric acid, being reddened by the acid. This second group may be divided into a-barbaloins, obtained from Barbadoes aloes, and reddened in the cold, and b-barbaloins, obtained from Socotrine and Zanzibar aloes, reddened by ordinary nitric acid only when warmed or by fuming acid in the cold. Nataloin (2C17H13O7·H2O) forms bright yellow scales. Barbaloin (C17H18O7) forms yellow prismatic crystals. Aloes also contain a trace of volatile oil, to which its odour is due.[citation needed]
Aloe vera
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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.
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.
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.
Uses
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, colourless and odourless. 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.
Uses
Aloe species are frequently cultivated as ornamental plants both in gardens and in pots. Many Aloe species are highly decorative and are valued by collectors of succulents. Some species, in particular Aloe vera are purported to have medicinal properties.
Other use of Aloes include their role in alternative medicines (see Herbalism) and in home first aid. Both the translucent inner pulp as well as the resinous yellow exudate from wounding the Aloe plant is used externally to relieve skin discomforts and internally as a laxative. To date, some research has shown that Aloe vera produces positive medicinal benefits for healing damaged skin. Conversely, other research suggests Aloe vera can negatively effect healing (Vogler and Ernst, 1999).
Some Aloe species have also been used for human consumption. For example, drinks made from or containing chunks of aloe pulp are popular in Asia as commercial beverages and as a tea additive; this is notably true in Korea.
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 produces remains 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 [citation needed]. 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.[1]
Internal uses
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Aloe contains a number of medicinal substances used as a purgative. The medicinal substance is produced from various species of aloe, such as A. vera, A. vulgaris, A. socotrina, A. chinensis, and A. perryi. Several kinds of aloes are commercially available: Barbadoes, Socotrine, Hepatic, Indian, and Cape aloes. Barbadoes and Socotrine are the varieties most commonly used for curative purposes [citation needed].
Aloes is the expressed juice of the leaves of the plant. When the leaves are cut, the juice that flows out is collected and evaporated. After the juice has been removed, the leaves are sometimes boiled to yield an inferior kind of aloes. The juice of the leaves of certain species, e.g. Aloe venenosa, is poisonous.
There have been very few properly conducted studies about possible benefits of aloe gel taken internally. One study found improved wound healing in mice. Another found a positive effect of lowering risk factors in patients with heart disease. Some research has shown decreasing fasting blood sugar in diabetic animals given aloe [2]. None of these studies can be considered to be definitive, and there are many false advertising claims for aloe.
Aloe has been marketed as a remedy for coughs, wounds, ulcers, gastritis, diabetes, cancer, headaches, arthritis, immune-system deficiencies, and many other conditions when taken internally. However, these uses are unsubstantiated; the only substantiated internal use is as a laxative. Furthermore, there is evidence of potential adverse side effects (for example, acute hepatitis[1]). Although some studies suggest that certain components of aloe such as aloe-emodin have genotoxic activity, human clinical trials and rodent carcinogenicity studies do not substantiate a genotoxic risk to humans when aloe products are consumed as directedBrusick D, Mengs U (1997). Assessment of the genotoxic risk from laxative senna products. Environ Mol Mutagen 29 (1): 1-9. PMID 9020301..
On 9 May 2002, the U.S. Food and Drug Administration issued a final rule banning the use of aloe and cascara sagrada as laxative ingredients in over-the-counter drug products[3].
In homeopathic medicine aloe is used for hemorrhoids[2].
ReferencesISBN links support NWE through referral fees
- ↑ Acute hepatitis induced by an Aloe vera preparation: a case report
- ↑ Morrsion, MD, Roger (1993). Desktop guide to keynotes and comfirmatory symptoms. Grass Valley, CA: Hahnemann Clinic Publishing.
- Schmidt JM, Greenspoon JS (1991) Aloe vera dermal wound gel is associated with a delay in wound healing. Obstet Gynecol 1: 115-117.
- Vogler BK, Ernst E (1999) Aloe vera: a systematic review of its clinical effectiveness British Journal of General Practice 49: 823-828.
- International Aloe Science Council: http://www.iasc.org/aloe.html
- University of Maryland Medical Center: http://www.umm.edu/altmed/ConsHerbs/Aloech.html
- Craig, Winston. The All-purpose Gel. Vibrant Life July 2001.
- Farrar, Maureen Meyers. Skin Deep. Better Nutrition July 2005.
- British Journal of General Practice, October 1999
Longe, Jacqueline L. 2005. The Gale encyclopedia of alternative medicine. Farmington Hills, Mich: Thomson/Gale. http://galenet.galegroup.com/servlet/eBooks?ste=22&docNum=CX3435199999&q=gvltec%5Fmain. ISBN: 0787693960
- Carrington Laboratories Veterinary Research with Acemannan Immunostimulant™
- 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
Links
List of Southern African indigenous trees
External links
Images
Aloe arborescens
Aloe aristata
Aloe dichotoma
Aloe hereroensis
Aloe lateritia
Aloe parvula
Aloe saponaria
Aloe saponaria flower
Aloe striatula
Aloe - unidentified
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