ALOE VERA
ALOE VERA by Rena Davis, MSc. Copyright © 2007
Scientific Names: Aloe vera L., A. perryi Baker (Zanzibar or Socotrine aloe), A. barbadensis Miller (also called A. vera Tournefort ex Linne or A. Vulgaris Lamark Curacao or Barbados aloe), or A. ferox Miller (Cape aloe). A. vera Miller and A vera L. may not be the same species.
Common names: Cape, Zanzibar, Socotrine, Curacao, or Barbados aloe, aloe vera
The name aloe is derived from the Arabic “alloch” which means a “bitter and shiny substance”. Drawings of aloe have been found in wall carvings of Egyptian temples erected in the fourth Millennium B.C. The Egyptian Book of Remedies (ca. 1500 B.C.) annotates the use of aloe in curing infections, treating the skin, and preparing drugs that were primarily used as laxatives. The Bible references aloe in John 19: 39-40, saying that Nicodemus brought a mixture of aloe and myrrh for the preparation of Christ’s body. Old lore states that Alexander conquered the island of Socotra to obtain control of aloe. The application of aloe for treatment of wounds, genital ulcers, hemorrhoids, and to stop hair loss was recorded by the Greek physician Dioscorides in 74 A.D. In the modern clinical era, the use of aloe began in the 1930’s as a treatment for roentgen dermatitis.
Aloe yields two commercially important products. “Aloe resin” is a solid residue obtained by evaporation of the latex obtained from cells (pericyclic) just beneath the skin. This bitter yellow latex contains anthraquinone barbaloin (a glucoside of aloe-emodin) and iso-barbaloin in addition to a Series of o-glucosides of barbaloin, called aloinosides, chrysophanic acid, and up to 63% resin. A valuable crystalline form of aloin is produced from the resin which contains a mixture of water soluble glycosides. Aloe-emodin exerts dose-dependent growth inhibition of H. pylori through inhibition of N-acetyltransferase (NAT) activity (Wang, 1998). Antibacterial effects have been demonstrated on four strains of methicillin-resistant Staphylococcus aureus (Hatano, 1999). Aloe-emodin is directly viracidal to herpes simplex virus type 1 and type 2, varicella-zoster virus, pseudorabies virus, and influenza virus (Sydiskis, 1991). Aloe gel, a clear gelatinous material obtained by crushing the cells found in the inner tissue of the Inner leaf, is the second commercially important product. The gel is used most frequently in the cosmetic and health food industries. The gel is a rich source of the polysaccharide glucomannan, the component believed to contribute significantly to the emollient quality of the gel.
Aloe vera contains Vitamins C, E, and zinc, which are all important for wound healing. Glycoproteins in aloe gel inhibit and break down bradykinin, a mediator of pain and inflammation. Aloe gel also inhibits Thromboxane which causes inflammation. Aloe gel stimulates fibroblast and connective tissue formation, a healing action rarely found in other anti-inflammatories. The polysaccharides in aloe seem to stimulate skin growth and repair. Aloe increases blood flow to burned tissue, therefore augmenting the healing rate. Aloe gel has been particularly beneficial in healing diabetic leg ulcers because, along with other wound healing capabilities, it lowers blood sugar.
Aloe gel’s antibacterial and antifungal ability compares favorably with the drug silver sulfadiazine, an antiseptic commonly used in the treatment of extensive burns. Aloe vera extract has been shown to kill Pseudomonas aeruginosa, Klebsiella pneumoniae, Serratia marcescens, Citrobacter species, Enterobacter cloacae, Streptococcus pyogenes, Streptococcus agalactiae, Escherichia coli, Streptococcus faecalis, and Candida albicans.
Acemannan, an antiviral component of aloe juice, is a powerful immune system stimulant. It works through enhancement of macrophage activity, the function of T cells and interferon production.
Acemannan has been effective for the treatment of HIV, influenza, and measles. It has demonstrated a direct antiviral effect on HIV by inhibiting glycosylation of glycoproteins. Acemannan, combined with suboptimal non-cytotoxic concentrations of AZT, acts synergistically in inhibition of replication of HIV and herpes simplex virus type 1.
References
Blitz JJ, et al. Aloe vera gel in peptic ulcer therapy; preliminary report. J Am Osteopath Assoc. 1963;62:731-735.
Danhof I. Potential benefits of orally-injested (sic: ingested) internal aloe vera gel. International Aloe Science Council Tenth Annual Aloe Scientific Semina; 1991; Irving, Texas.
Grindlay D, Reynolds T. The aloe vera phenomenon: a review of the properties and modern uses of the leaf parenchyma gel. JEthnopharmacol. 1986;16:117-151.
Hatano T, Uebayashi H, Ito H et al, Phenolic constituents of cassia seeds and the anti bacterial effects of some naphthalenes and anthraquinones on methicillin resistant Staphylococcus aureus.
Sydiskis RJ, Owen D G, Lohr JL et al., Inactivation of enveloped viruses by anthraquinones extracted from plants. Antimicrob Chemother 1991 Dec; 35(12):2463-6.
Saoo K et al. Antiviral activity of aloe extracts against cytomegalovirus. Phytother Res. 1996;10:348-350.
Vazquez B, et al. Anti-inflammatory activity of extracts from aloe vera gel. J Ethnopharmacol. 1996;55:69-75.
Wang HH, Chung JG, Ho CC, Wu LT, Chang SH. Aloe-emodin effects on arylamine N-acetyltransferase activity in the bacterium Helicobacter pylori. Planta Med 1998 Mar;64(2):176-178.
Zhang L, Tizard IR, Activation of mouse macrophage cell line by acemannan: the major carbohydrate fraction from aloe vera gel. Immunopharmacology 1996 Nov; 35(2): 119-128.
