Science Fair Project Encyclopedia
They are succulent plants. Members of the closely allied genera Gasteria and Haworthia , with a similar mode of growth, are also cultivated and popularly known as aloes.
They are cultivated as ornamental plants, especially in public buildings and gardens, for their stiff, rugged habit.
The plants are apparently stemless, bearing a rosette of large, thick, fleshy leaves, or have a shorter or longer (sometimes branched) stem, along which, or towards the end of which and its branches, the generally fleshy leaves are borne.
The leaves are generally lance-shaped with a sharp apex and a spiny margin, but vary in colour from grey to bright green and are sometimes striped or mottled.
The rather small tubular yellow or red flowers are borne on simple or branched leafless stems and are generally densely clustered.
The juice of the leaves of certain species yields aloes (see below). In some cases, as in Aloe venenosa, the juice is poisonous. The plant called American aloe, Agave americana, belongs to a different family, Agavaceae.
Aloes is a medicinal substance used as a purgative and produced from various species of aloe, such as A. vera, vulgaris, socotrina, chinensis, and perryi. Several kinds of aloes are distinguished in commerce--Barbadoes, Socotrine, hepatic, Indian, and Cape aloes. The first two are those commonly used for medicinal purposes. Aloes is the expressed juice of the leaves of the plant. When the leaves are cut the juice flows out and is collected and evaporated. After the juice has been obtained, the leaves are sometimes boiled, to yield an inferior kind of aloes.
From these plants active principles termed aloins are extracted by water. According to W. A. Shenstone , two classes 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 this reagent. 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, 2C17H13O7ˇH2O, forms bright yellow scales, melting at 212-222 ° barbaloin, C17H18O7, forms yellow prismatic crystals. Aloes also contain a trace of volatile oil, to which its odour is due.
The dose is 2 to 5 grains, that of aloin being 1/2 to 2 grains. Aloes can be absorbed from a broken surface and will then cause purging. When given internally it increases the actual amount as well as the rate of flow of the bile. It hardly affects the small intestine, but markedly stimulates the muscular coat of the large intestine, causing purging in about fifteen hours. There is hardly any increase in the intestinal secretion, the drug being emphatically not a hydragogue cathartic. There is no doubt that its habitual use may be a factor in the formation of haemorrhoids; as in the case of all drugs that act powerfully on the lower part of the intestine, without simultaneously lowering the venous pressure by causing increase of secretion from the bowel. Aloes also tends to increase the menstrual flow and therefore belongs to the group of emmenagogues. Aloin is preferable to aloes for therapeutic purposes, as it causes less, if any, pain. It is a valuable drug in many forms of constipation, as its continual use does not, as a rule, lead to the necessity of enlarging the dose. Its combined action on the bowel and the uterus is of especial value in chlorosis, of which amenorrhoea is an almost constant symptom. The drug is obviously contraindicated in pregnancy and when haemorrhoids are already present. Many well-known patent medicines consist essentially of aloes.
Drinks made from aloe pulp are popular in Asia, especially in Korea, as commercial beverages, and as a tea additive.
The lign-aloes is quite different from the medicinal aloes. The word is used in the Bible (Numbers 24:6), but as the trees usually supposed to be meant by this word are not native in Syria, it has been suggested that the Septuagint reading in which the word does not occur is to be preferred. Lign-aloe is a corruption of the Latin lignum-aloe, a wood, not a resin. Dioscorides refers to it as agallochon, a wood brought from Arabia or India, which was odoriferous but with an astringent and bitter taste. This may be Aquilaria agallochum, a native of East India and China, which supplies the so-called eagle-wood or aloes-wood, which contains much resin and oil.
The thick mucilaginous gel is an ideal home first aid cure for burns, wounds, and sunburn. It is also useful for any dry skin condition, especially eczema around the eyes and sensitive facial skin, and can be used for treating fungal infections such as ringworm. In Ayurvedic medicine, the gel is usually applied fresh and can even be converted into an ointment for long-term use.
Extracts of the leaves were once used on children's fingers to stop nail-biting.
Unproven Medical Benefits
Aloe vera has been widely marketed as having a number of benefits when taken internally. For example, Aloe has been marketed as a remedy for coughs, wounds, ulcers, diabetes, cancer, headaches, arthritis, immune-system deficiencies, and many other conditions. However, these uses are unproven. The only substantiated internal use is as a laxative. Furthermore, there is evidence of significant adverse side effects. Consult your doctor when contemplating taking Aloe internally.
Sources of Aloe Vera
- Aruba Aloe
- Aloe FLP Forever Living Products, become Distributor and get 30% off, best opportunity
- Aloe vera Forever Living Products are the world's largest grower of Aloe Vera
Eclectic herbal information
- Aloe vera King's American Dispensatory @ Henriette's Herbal
- Alonium (Aloin) King's American Dispensatory @ Henriette's Herbal
- Aloe Mrs. Grieve's "A Modern Herbal" @ Botanical.com
- Aloe vera HerbMed
- Aloe vera (pdf) Longwood Herbal Task Force
- Aloe vera Memorial Sloan-Kettering Cancer Centre
- Notes on Aloe Vera "Some Notes on Aloe Vera" by Beth Lulinski, R.D. and Cathy Kapica, Ph.D., R.D.
- Aloe (aloe) "Kent's Lectures on Homeopathic Materia Medica" by Dr Robert Séror
- Aloe "A Primer of Materia Medica for practitioners of Homœopathy" by Timothy Allen
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