encyclopedia

Aloe

  

Scientific Names:

Aloe ferox MILLER and Aloe barbadensis MILLER [Fam. Aloaceae]    
     
Forms:    

Dried leaf latex; dry extract of aloe latex; leaf acemannan hydrogel; aloe gel.    
     
Traditional Usage:     
     
– Anal fissures (latex)
– Antibacterial (gel)
– Anti-diarrheal (latex)
– Antifungal  (gel)
– Antinflammatory (gel and latex)
– Antimicrobial (gel and latex)
– Antiretroviral  (gel)
– Antiviral  (gel)
– Burns (gel)
– Cankers (acemannan hydrogel)
– Cellular Regeneration (gel and latex)
– Cleansing (gel and latex)
– Constipation (latex)
– Detoxifying (gel and latex)
– Hemorrhoids (latex)
– HIV (acemannan hydrogel)
– Hyperglycemia (gel)
– Laxative (latex)
– Pre and Post Operative Cleansing  (latex)
– Psoriasis (gel)
– Skin Wounds and Sores (gel)
– Ulcers (gel)
    
 
Overview:    

The leaf gel of aloe, Aloe ferox MILLER and Aloe barbadensis MILLER (otherwise known as Aloe vera) [Fam. Aloaceae], has been used to soothe burns and heal wounds since ancient times, dating back at least 4000 years. In the New Testament (John 19:39) reference is made to an ointment made of myrrh and aloe to embalm the body of Jesus. Aloe was a secret beauty aid of Egyptian queens including Cleopatra and Nefertiti and was considered a “plant of immortality” in ancient Egypt. Soothing Aloe vera gel comes from the central part of the leaves while bitter laxative latex comes from cells closer to the leaf rind. In addition, a polysaccharide called acemannan from aloe leaf rind has been found to impair the ability of viruses, including retroviruses like HIV, to infect healthy T-cells. Traditional uses of aloe include for treating hives, insect stings and bites, rashes, sunburn, swelling and skin wrinkles. In a clinical trial to test the effect of Aloe vera gel and mild soap versus mild soap alone in preventing skin reactions in patients undergoing radiation therapy, a protective effect of adding aloe to the soap regimen was observed. Aloe vera was first valued as a trade commodity around the world for its laxative properties. The bitter latex is rich in anthraquinones including aloe-emodin and chrysophanol and is an effective laxative for acute constipation, although it is not recommended for chronic constipation due to its potentially lethal effects in high dosages. The German pharmacopoeia recommends aloe for treating acute constipation, for emptying the bowels before X-rays, before and after abdominal operations and for all disorders in which defecation with a soft stool is desired, e.g. anal fissures, hemorrhoids and after rectal operations. Human clinical trials also prove aloe effective for treating psoriasis, cankers and lowering blood sugar.    
             
     
Active Ingredients:    

Aloe dried latex contains: Approximately 13-27% aloins A and B (barbaloin, aloin, and glucosyl diastereoisomers of aloe-emodin anthrone). Aside from aloinosides A and B, other hydroxyanthracene derivatives are also present. 5-hydroxyaloin is characteristic of Cape aloes while 7- hydroxyaloin is found in Barbados aloe; small amounts of anthraquinones including aloe-emodin and chrysophanol. Chromone derivatives including 25-40% aloeresins A and B and smaller amounts C. Aloenin B (aloenin A and p-coumaroyl-glucose); p-coumaric acid methyl ester also occurs. Aloe gel contains: water; polysaccharides including acemannan; fatty acids including gamma linolenic acid; prostaglandins; salicylic acid; saponins; sterols; vitamins E and C; minerals including zinc; 20 amino acids (out of 22 required by the human body); and lectins.    
             
     
Suggested Amount:    

Aloe gel: For external use on superficial skin wounds and other skin conditions, apply as needed several times per day. Aloe gel juice: For internal use, take 1 to 2 teaspoons up to three times daily. Aloe latex: For acute constipation: Unless otherwise prescribed, aloe is used with the average daily dosage of 0.05-0.2 g; powdered aloe (0.1-0.2g daily) or aloe dry extract (0.05-0.1g daily). The average daily dosage as a laxative contains 20-60mg hydroxyanthracene derivatives. CAUTION: Pure aloe latex is classified as a drug and is not recommended for use without the supervision of a qualified physician.    
             
     
Drug Interactions:    

Aloe gel: None known. Aloe latex: In large dosages, the anthraquinones-type laxative compounds may increase the action of other laxatives and should not be taken at the same time. With chronic use/abuse, a potassium deficiency may develop that may potentiate the effects of cardiotonic glycosides. Use of aloe gel juice taken internally may lower blood glucose levels and interfere with existing hypo- or hyperglycemia therapy (hypoglycemics include: insulin, Glucophage(R) metformin, DiaBeta(R) Glynase(R) glyburide, Glucotrol(R) glipizide).    
             
     
Contraindications:    

Aloe gel: None known. Aloe latex: Laxatives are contraindicated in the case of impacted bowel (serious bowel obstruction) or ileus of any origin (danger of intestinal rupture). Stimulant laxatives are also not recommended for the treatment of chronic constipation. Aloe laxatives should also not be taken during pregnancy due to abortifacient action or during lactation because a proportion of the active aglycones reach the mother's milk. Aloe is also contraindicated in cases of kidney complaints and for menstruating women.    
             
     
Side Effects:    

Aloe gel: Used externally, aloe gel has been reported to delay wound healing in deep wounds and surgical incisions including after laparotomy or caeasarean delivery. There have also been rare reports of allergic reaction to aloe gel applied externally. Taken internally, large dosages of aloe gel juice may have a laxative effect. Aloe latex: Overdose can lead to painful stomach cramps and diarrhea. Toxic doses of aloes cause severe hemorrhagic diarrhea and kidney damage, and sometimes death. The lethal dose is stated to be 1g/day taken for a period of several days. Like all other anthracene-glycoside laxatives, aloe should not be used continuously over a prolonged period as this disturbs the water and electrolyte balance of the body. An increased loss of water and salts, especially potassium salts, may occur and ultimately a dangerous electrolyte imbalance can develop that can be fatal if it persists. Large doses of aloe may also cause gastric disturbance, nausea and diarrhea due to anthraquinones-type laxative compounds. Chronic use of sennoside laxatives often causes pseudomelanosis coli and therefore should be avoided for this reason as well. A recent study suggested that pseudomelanosis coli is associated with an increased colorectal cancer risk.    
             
     
References:     

     
Choi SW, Son BW, Son YS, Park YI, Lee SK, Chung MH. 2001. The wound-healing effect of a glycoprotein fraction isolated from aloe vera. Br J Dermatol. 2001 Oct; 145(4): 535-45.
 
Ishii Y, Takino Y, Toyo'oka T, Tanizawa H. 1998. Studies of aloe. VI. Cathartic effect of isobarbaloin. Biol Pharm Bull. 1998 Nov; 21(11): 1226-7.
 
McCaleb, RS, Leigh, E, Morien, K. 2000. Aloe in The Encyclopedia of Popular Herbs. Publ. by Prima Publishing, 3000 Lava Ridge Court, Roseville, CA 95661. Pp. 41-52.
 
Olsen DL, Raub W Jr, Bradley C, Johnson M, Macias JL, Love V, Markoe A. 2001. The effect of aloe vera gel/mild soap versus mild soap alone in preventing skin reactions in patients undergoing radiation therapy. Oncol Nurs Forum. 2001 Apr; 28(3): 543-7.
 
Wichtl M (ed). 1994. Aloe barbadensis/capensis – Barbados/Cape Aloe (English translation by Norman Grainger Bisset). In Herbal Drugs and Phytopharmaceuticals. CRC Press, Stuttgart, pp. 59-62.