Aloe Herb - Uses, Benefits and Dosage for Aloe

Taxonomic Class

Asphodelaceae or Liliaceae

Common Trade Names

Multi-ingredient preparations: All Natural Aloe Vera Gel, AloeCeuticals Snow and Sun Sunburn Spray (Lip Balm, Gel), Aloe Flex Orthopedic Cream, Aloe Grande, Aloe Life, Aloe Shield (Soft Gel Capsules), Aloe Vera Gel, Aloe Vera Inner Leaf Capsules, Aloe Vera Jelly, Aloe Vera Juice, Aloe Vera Ointment, Aloe Vesta Perineal, Benzoin Compound Tincture, Carrasyn Gel Wound Dressing, Dermaide Aloe, Whole Leaf Aloe Vera Juice

Common Forms

Capsules: 75 mg, ] 00 mg, 200 mg aloe vera extract or aloe vera powder

Gel: 98%, 99.5%, 99.6% aloe vera gel

Juice: 99.6%, 99.7% aloe vera juice

Also available as cream, hair conditioner, jelly, juice, liniment, lotion, ointment, shampoo, skin cream, soap, and sunscreen as well as in facial tissues.

Source

Aloe gel is obtained from the center parenchymatous tissues of the large bladelike leaves of Aloe vera (also referred to as Aloe barbadensis, Aloe vulgaris hybrids, Aloe africana, Aloe ferox, Aloe perryi, and Aloe spicata). Orally ingested preparations are composed of either the colorless juice from secretory cells located just below the leaf epidermis or a solid yellow latex obtained by evaporating the juice.

Commercial products are available as topical and oral preparations. Topical preparations contain a colorless mucilaginous gel called aloe gel or aloe vera gel. Sometimes this gel is erroneously called aloe juice. Aloe gel is prepared by various methods, with variable consistencies and stability, although fresh gel from the plant may be preferred.

Chemical components

The chemical composition of aloe varies, depending on the species and the environmental growing conditions. The juice and latex contain hydroanthraquinone derivatives (1 O-C- D-glucosyl diastereoisomers of aloe-emodin anthrone), including anthraquinone glycosides aloin A and B (formerly known as barbaloin and isobarbaloin, respectively). A reddish black glistening residue known as aloin (a mixture of aloin A and aloin B) is produced when the latex is filtered and dried.

Aloe gel, in contrast, is mostly water. Other gel compounds include bradykininase, a serine carboxypeptidase, magnesium lactate, organic acids, steroids, sugars, vitamins, and the polysaccharides acemannan and glucomannan. Because mechanical separation of gel from latex is not always complete, aloe gel may accidentally contain anthraquinone glycosides from the latex.

Actions

When taken internally, aloin is cleaved by intestinal bacteria and produces a metabolite that irritates the large intestines and stimulates colonic motility, propulsion, and transit time. In addition, aloin causes active secretion of fluids and electrolytes in the lumen and inhibits reabsorption of fluids from the colon. These actions produce a feeling of distention and increase peristalsis. The cathartic effect occurs 8 to 12 hours after ingestion.

When used externally, besides acting as a moisturizer on burns and other wounds, aloe reduces inflammation, possibly by blocking production 9f thromboxane A2' inactivating bradykinin, inhibiting prostaglandin A2, and inhibiting oxidation of arachidonic acid.

Aloe's antipruritic effect may result from blockage of the conversion of histidine to histamine as a result of the inhibition of histidine decarboxylase. Wound healing is believed to result from increased blood flow to the wounded area.

Some in vitro studies have demonstrated that aloe juice and aloe gel preparations inhibit the growth of bacteria and fungi commonly isolated from wounds and burns. Other studies have found inconsistent activity in this regard. Conflicting results may be due to variable content of the aloe preparations and deterioration of some of the active compounds. Because the identification and stability of the active components are unknown, the clinical relevance of claims of antibacterial and antifungal effects remains unknown.

In vitro and murine studies suggest that aloe-emodin may hold some promise as a useful entity for treating neuroectodermal tumors because of its unique cytotoxicity profile.

Reported Uses

Therapeutic claims center on aloe's use externally as a topical gel for cuts, frostbite, minor burns, skin irritation, sunburn, and other dermal wounds and abrasions. Numerous studies have validated these claims by demonstrating that topical application of aloe gel decreases acute inflammation, promotes wound healing, reduces pain, and exerts an antipruritic effect .

Internally, the dried latex has been claimed to be useful as a stimulant laxative. Other claims for use of aloe include amenorrhea, asthma, bleeding, colds, seizures, and ulcers. No medical evidence supports the clinical application of aloe for these conditions.

Aloe preparations have also been considered for use in the treatment of acne, AIDS, arthritis, asthma, blindness, bursitis, cancer, colitis, depression, diabetes, glaucoma, hemorrhoids, multiple sclerosis, peptic ulcers, and varicose veins. Few, if any, well-controlled clinical trials substantiate the use of aloe for any of these disorders.

One controlled trial comparing a gel formulation of aloe, allantoin, and silicon dioxide failed to show a significant clinical benefit for the therapy of recurrent oral aphthous ulcers . Another trial failed to find benefit of an acemannan hydrogel dressing derived from aloe vera over that of moist saline gauze for the treatment of pressure ulcers .

Although several significant criticisms of the study can be made, one preliminary trial suggests a potential benefit for the combination of aloe tincture (1 ml P.O. b.i.d.) and melatonin (20 mg/day) in the therapy of patients with advanced solid tumors .

Dosage

For burns, pruritus, skin irritation, and other wounds (external forms), aloe may be applied liberally as needed. Although internal use is not recommended, some sources suggest 100 to 200 mg of aloe or 50 to 100 mg of aloe extract P.O., taken in the evening. Information about dosages for aloe juice is lacking.

Adverse Reactions

• GI: damage to intestinal mucosa (may be irreversible), harmless brown discoloration of intestinal mucosa (with frequent use), painful intestinal spasms, severe hemorrhagic diarrhea.

• GU: kidney damage, red discoloration of urine (with frequent use).

• Hematologic: accumulation of blood in pelvic region (with large doses).

• Metabolic: fluid and electrolyte loss from frequent use, hypokalemia.

• Skin: contact dermatitis, delayed wound healing because of reduced oxygen permeability (topical forms).

Other: spontaneous abortion or premature birth (during the third trimester of pregnancy).

Interactions

Antiarrhythmics, cardiac glycosides, loop diuretics, other potassium wasting drugs, corticosteroids, thiazides: Increased effects of these drugs when aloe is used internally. Avoid internal use of aloe.

contraindications And Precautions

External aloe preparations are contraindicated in patients known to be hypersensitive to aloe or in those with a history of allergic reactions to plants in the Liliaceae family (garlic, onions, and tulips). Internal use is contraindicated in pregnant or breast-feeding patients, during menstruation, in children, and in patients with renal or cardiac disease (because of the potential for hypokalemia and, possibly, disturbance of cardiac rhythm).

Special Considerations

• Alert Inform the patient that oral use can cause severe abdominal discomfort and serious hypokalemia and other electrolyte imbalance.

• Alert Unapproved use of aloe vera injections for cancer has been associated with the death of four patients . Use of injectable aloe vera preparations or chemical constituents of aloe vera is not recommended.

• Alert Reflex stimulation of uterine musculature may cause spontaneous abortion or premature birth during the third trimester of pregnancy.

• Alert Overdose may result in severe hemorrhagic diarrhea, kidney damage and, possibly, death.

Caution the patient against the internal use of aloe vera gel and aloe vera juice.

Commentary

Aloe has a long history of popular use, and topical application is generally considered safe. The FDA does not recommend aloe for any specific condition. Fresh aloe may be useful for the treatment of burns and minor tissue injury, but studies are not well documented. Because aloe laxatives that contain anthraquinone produce dramatic cathartic effects, less toxic laxatives should be used. Few studies support the use of aloe juice for internal consumption. Although a recent in vitro study found that aloe-emodin exerts genotoxic activity further research is needed regarding its use as an anticancer agent.