Aloe vera, a member of the lily family, is a spiky, succulent, perennial plant. It is indigenous to eastern and southern Africa, but has been spread throughout many of the warmer regions of the world, and is also popularly grown indoors. There are about 300 identified species, but Aloe vera ("true aloe") is the most popular for medical applications. It has also been known as Aloe vulgaris ("common aloe") and Aloe barbadensis. The plant has yellow flowers and triangular, fleshy leaves with serrated edges that arise from a central base and may grow to nearly 2 ft (0.6 m) long. Each leaf is composed of three layers. A clear gel, that is the part of the plant used for topical application is contained within the cells of the generous inner portion. Anthraquinones, which exert a marked laxative effect, are contained in the bitter yellow sap of the middle leaf layer. The fibrous outer part of the leaf serves a protective function.
Aloe vera has been in use for thousands of years, and is mentioned in records as long ago as 1750 b.c. Use of the plant is thought to have originated in Egypt or the Middle East. It was reputedly used in Egyptian embalming procedures, as drawings of Aloe vera have been found on cave walls in the region. Legend has it that Aloe vera was one of Cleopatra's secrets for keeping her skin soft. Pliny and Dioscorides of ancient Greece wrote of the healing effects of this plant. Additionally, Alexander the Great is said to have acquired Madagascar so that he could utilize the Aloe vera growing there to treat soldiers' wounds . It is also a remedy which has long been used in the Indian practice of Ayurvedic medicine .
In the United States, Aloe vera was in use by the early 1800s, but primarily as a laxative. A turning point occurred in the mid-1930s, when a woman with chronic and severe dermatitis resulting from x-ray treatments was healed by an application of Aloe vera leaf gel. Success with this patient encouraged trials with others suffering from radiation burns . Evidence of the effectiveness remained anecdotal until 1953, when Lushbaugh and Hale produced a convincing study, using Aloe vera to treat beta radiation lesions in rats. Other experimental protocols have been carried out using animals since that time, but there is little human research data to describe the degree of effectiveness of Aloe vera treatment. Some evidence suggests that it is especially helpful in the elderly and other people with impaired health or failing immune systems.
Aloe vera contains a wealth of substances that are biologically active. The laxative, and in large doses, purgative, effects of Aloe vera latex are attributable to a group of chemicals known as the anthraquinones. Aloin,
barbaloin, and aloe-emodin, and aloectic acid, are a few of the anthraquinones contained in the latex layer. The latest, and perhaps most exciting component discovered in Aloe vera is a biologically active polysaccharide known as acetylated mannose, or acemannan. This substance has been shown to be a highly effective immune stimulant, with activity against the viruses causing the flu, measles , and early stages of AIDS . It has been used effectively against some veterinary cancers, most notably sarcoma, and is being investigated as an agent to be used to treat cancer in humans. Acemannan is one of many saccharides contained in Aloe vera. Some of the others are arabinose, cellulose, galactose, mannose, and xylose. Prostaglandins are a third important set of compounds, and are thought to play a major role in wound healing. Aloe vera also contains fatty acids, enzymes, amino acids , vitamins, minerals, and other substances. The interaction of all these components produces a favorable environment for wound healing.
Few botanicals are as well known or as highly thought of as the Aloe vera plant. Throughout recorded history, it has been used to keep skin beautiful and restore it to health. A frequent moisturizing ingredient in cosmetics and hair care products, it also promotes the healing of burns and superficial wounds, but should not be used on deep or surgical wounds of punctures. Topical application has been successful in treatment of sunburn , frostbite, radiation injuries , some types of dermatitis, psoriasis , cuts, insect stings, poison ivy, ulcerations, abrasions, and other dermatologic problems. Healing is promoted by the anti-inflammatory components, including several glycoproteins and salicylates, and substances that stimulate growth of skin and connective tissue. Aloe vera contains a number of vitamins and minerals that are necessary to healing, including vitamin C, vitamin E , and zinc . It also exerts antifungal and antibacterial effects, and thus helps to prevent wound infections . One study showed it to have a little more activity than the antiseptic silver sulfadiazine against a number of common bacteria that can infect the skin. It has moisturizing and pain relieving properties for the skin lesions, in addition to healing effects.
Aloe vera gel products may also be used internally. They should not contain the laxative chemicals found in the latex layer. There is some evidence that Aloe vera juice has a beneficial effect on peptic ulcers, perhaps inhibiting the causative bacteria, Helicobacter pylori. It appears to have a soothing effect on the ulcer, and interferes with the release of hydrochloric acid by the stomach. Colitis and other conditions of the intestinal tract may also respond favorably to the internal use of gel products. Aloe vera has been shown to exert a stabilizing effect on blood sugar in studies done on mice, indicating a possible place for it in the treatment of diabetes. One study suggested that giving Aloe vera extract orally to patients with asthma who are not dependent on steroids could improve symptoms. A health care provider should be consulted about these uses. Other suggested, but insufficiently proven, indications for oral Aloe vera gel include prevention of kidney stones and relief of arthritis pain.
Aloe vera products derived from the latex layer are taken orally for the laxative effect. They can cause painful contractions of the bowel if taken in high doses. Milder measures are recommended first.
The concentration of the immune stimulant acemannan is variable in the natural plant, as well as gel and juice products, but it is also available in a purified, standardized, pharmaceutical grade form. An injectable type is used in veterinary medicine to treat fibrosarcoma and feline leukemia , a condition caused by a virus in the same family as AIDS.
Choosing effective Aloe vera products can be challenging. Once a leaf is cut, enzymes start to break down some of the long chain sugars which make Aloe vera gel an effective healing product, so it is important for the plant to have been properly handled and stabilized. Ask for help in selecting a reputable company to buy from. When shopping for a product to use for topical healing, look for Aloe vera to be one of the first products listed to ensure that it is not too dilute to be efficacious. Commercial, stabilized gel products may not work as well as the fresh gel, but cold processing is thought to best retain the beneficial properties. The FDA does not regulate labeling of Aloe vera products.
Aloe vera juice is most often the form of the gel that is used internally. At least half of the juice should be Aloe vera gel. If laxative properties are not desired, be sure that the juice does not contain latex. A product that is made from the whole leaf does not necessarily contain anthraquinones from the latex layer, as those are water-soluble and can be separated out during processing. Capsules and tinctures of the gel are also available. Oral forms of the latex extract are generally capsules, as it is extremely bitter.
Growing aloe at home
For common topical use, keeping an Aloe vera plant at home is one of the easiest ways to get the freshest and most concentrated gel. It is easy to cultivate, requiring only good drainage, mild temperatures, and occasional watering. Bring the plant inside if outside temperatures are less than 40°F (4.4°C). It will tolerate either full or partial sunlight, but will require more frequent watering in full sun. Water it only when the soil has become dry. To use the gel, break off a leaf and cut it lengthwise to expose the inner layer. Scoop the gel out and apply generously to the area needing treatment. Discard whatever gel is not used immediately, as it will degenerate quickly. The inner portion of the leaf may also be applied directly to a skin injury, and bound to it.
Aloe vera gel is generally safe for topical use, but it is best to apply it to a small area first to test for possible allergic reaction. Stinging and generalized dermatitis may result in individuals who are sensitive to it. The vast majority of the warnings apply only to products containing anthraquinones, such as aloin and barbaloin (as well as the numerous others), which are found in the latex layer of the plant. Aloe vera latex should not be used internally by women who are pregnant or lactating, or by children. This product can cause abortion or stimulate menstruation . It may pass into the milk of breastfeeding mothers. People who have abnormal kidney function, heart disease , or gastrointestinal diseases are best advised to avoid any product containing Aloe vera latex or anthraquinones. Prolonged, internal use in high doses may produce tolerance so that more is required to obtain the laxative effect. Be aware of the possibility that any Aloe vera product for internal use that is supposed to contain only the gel portion can become contaminated by the anthraquinones of the latex layer. For this reason, people who have a contraindication for using Aloe vera latex should use caution when taking an Aloe vera gel product internally.
Internal use of Aloe vera latex may turn the urine red, and may also cause abdominal pain or cramps when products containing anthraquinones are consumed.
Chronic internal use of products containing Aloe vera latex may increase the likelihood of potassium loss when used concomitantly with diuretics or corticosteroids. It may possibly compound the risk of toxicity when used with cardiac glycosides (both prescription and herbal types) and antiarrhythmic drugs. Absorption of other oral medications can be decreased. Aloe vera latex should not be used with other laxative herbs, which may also lead to excessive potassium loss.
Internal use of Aloe vera gel can cause changes in blood sugar, so diabetics should monitor blood glucose levels during use, particularly if insulin or other pharmaceuticals are being used to control hyperglycemia.
Topical Aloe vera may enhance the effect of topical corticosteroids and allow a reduction in the amount of the steroid being used.
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Aloe is a medicinal plant with a history of use dating back to ancient Egypt. It may be most well known for its effects on easing sun burn. Aloe is a succulent plant from South Africa and is often used as a ornamental plant in the garden.
There are over 200 different species of aloe plants. The type used most often for medicinal purposes is Aloe barbadensis, also known as Aloe vera. Both Aloe barbadensis and Aloe arborescens are grown commercially. As a desert plant it cannot survive frost and is grown in the southern United States.
There are two separate medicinal products obtained from the aloe plant. The most common is the gel obtained from the inner tissue of the thick, fleshy leaves of aloe. The gel has gained acceptance as a base for nutritional drinks, a moisturizer for the skin and a healing agent in cosmetics. It can be found in numerous toiletry products and over-the-counter drugs. This gel can be manually squeezed out of a leaf of aloe and used directly on the skin. The gel is nutrient rich and, thus, has health benefits.
The leaves also produce a liquid juice or resin that is sometimes referred to as aloes, Aloin or aloe latex. This latex is yellowish in color and bitter tasting. It contains anthraquinone glycosides, which are potent laxatives . The aloe latex has a long history of use taken internally as a laxative.
The list of medicinal claims for aloe is extensive. In recent years several companies have made their mark in the aloe market through possibly questionable ethics and multilevel marketing techniques that exaggerated claims. The most well established uses for aloe are topically forminor skin conditions and as amoisturizer. For this reason, aloe is often found in cosmetics products.
Some of the claims and suggested uses for aloe include:
- oral use of Aloe vera to control blood sugar levels in people with type II diabetes
- oral use of aloe in cancer prevention has been investigated
- use as a laxative
- using aloe gel to treat minor wounds and inflammatory disorders of the skin as well as burns
- topical use to treat genital herpes
- topical use in a cream, for treatment of psoriasis
- topical use in a lotion for treating dandruff
- topical use as a treatment for radiation induced skin damage
- use as an immune stimulant
- uses for its antibacterial and antifungal activity
- oral use to relieve symptoms of stomach ulcer
- use in treating ulcers of the mouth or canker sores
Scientific data is weak on most of these claims. Research does support the use of aloe vera on first to second degree burns as well as for bed sores. There is a limited amount of data indicating that aloe may be useful to relieve inflammation due to inflammatory bowel disease when taken orally. Aloe latex is effective as a laxative but there may be safer laxatives to take when necessary.
No recommended dosage has been established for aloe or products containing aloe. Since the U.S. Food and Drug Administration (FDA) does not regulate herbs and supplements, the effective doses are often recommended by the manufacturer. In cosmetics, aloe gel is often used at 0.5%. It is generally accepted that aloe gel can be used liberally on the skin. The gel can be taken orally from 50-200 mg daily. For use as a laxative, the dried juice can be taken in capsule form from 40-200 mg daily. Establishing a recommended dose is difficult because the concentration of active ingredients varies from product to product. Product labels should be read for recommended dosages. Injection of aloe products is not recommended.
Some species of aloe are toxic and should not be used. People who grow their own aloe should be sure the species is safe for medicinal use. The most common aloe that is used medicinally is Aloe barbadensis. The FDA does not strictly regulate herbs and supplements so strength, purity and product safety may vary. It is important to know if purchased aloe is in the gel or latex form. The only use aloe latex is as a laxative. There is the potential that the latex fraction of aloe can cause uterine contractions so this drug should not be used during pregnancy. The gel form is safe in most instances. There have been reports of injected aloe causing death.
Aloe may cause allergic reactions or sensitivities in some people. Anyone with a known allergy to members of the Liliaceae family such as garlic , onions
QUESTIONS TO ASK YOUR PHARMACIST
- Is the aloe product I selected from the gel or the latex? (The latex is used as a laxative, while the gel is used for nutritional value and skin care.)
- How can I determine the proper dosage for my condition?
- Are there side effects I should be aware of?
or tulips should avoid aloe. If irritation occurs when using a product containing aloe its use should be stopped immediately. Oral consumption of aloe latex can cause abdominal pains, gastro-intestinal irritation and, in large amounts, can lead to kidney problems, bloody diarrhea and bleeding in the intestines. Aloe should not be used as a laxative for more than 1–2 weeks without medical supervision. When used on surgical wounds aloe gel has been found to slow the healing of the lesion.
There are no known drug interactions with aloe.
Caregivers should be aware of a patients use of aloe for medicinal purposes. They should review the recommended uses and dosages on the package label and monitor how and when the patient uses aloe for treatment. It is important that the caregiver recognize any allergic reactions or harmful side effects the patient experiences, especially from use as a laxative.
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Maenthaisong, R., N. Chaiyakunapruk, S. Niruntraporn, and C. Kongkaew. “The Efficacy of Aloe vera Used for Burn Wound Healing: A Systematic Review.” Burns 33, no. 6 (September 2007): 713–8.
Moore, Z. E., and S. Cowman. “Wound Cleansing for Pressure Ulcers.” Cochrane Database Systematic Reviews 4 (October 19, 2005): CD004983.
“Definition, Testing and Application of Aloe Vera and Aloe Vera Gel.” Nature4Science. http://www.nature4science.com/AloeVera/1_DescriptionofAloeVera.pdf.
Natural Standard Research Collaboration. “Aloe (Aloe vera).” MayoClinic.com. May 1, 2006 [cited April 9, 2008]. http://www.mayoclinic.com/health/aloevera/NS_patient-Aloe.
Cindy L.A. Jones Ph.D.
al·oe / ˈalō/ • n. 1. a succulent plant (genus Aloe) of the lily family, typically having a rosette of toothed fleshy leaves and bell-shaped or tubular flowers on long stems. ∎ (aloes or bitter aloes) a strong laxative obtained from the bitter juice of various kinds of aloe. ∎ (also American aloe) another term for century plant. 2. (aloes) (also aloeswood) the fragrant heartwood of a tropical Asian tree (genus Aquilaria, family Thymelaeaceae).