Use of Aloe to Heal Burn Wounds
Reviewed: Maenthaisong R, Chaiyakunapruk N, Niruntraporn S, Kongkaew C. The efficacy of aloe vera used for burn wound healing: a systematic review. Burns. 2007. In press.
The gel of the leaves of the aloe (Aloe vera, Aloeaceae) plant has long been used for many purposes, particularly for burn wound healing. The authors note that in their country of Thailand, aloe vera gel is included in the Thai Herbal Fundamental Public Health Drug List as burn wound therapy. They conducted a systematic review to determine the efficacy of topical aloe vera for the treatment of burn wounds.
An electronic search of 16 medical databases was conducted for relevant studies. The authors also reviewed the reference lists of retrieved articles and consulted experts in burn therapy. They included both published and unpublished controlled clinical trials of aloe for burn wound healing in any language. Two reviewers independently extracted data on study characteristics, patient characteristics, intervention, and outcome measures.
Of the 1069 articles identified, 4 studies (with a total of 371 patients) were included in this review: two were conducted in Thailand, one in India, and one in China. One Thai study( n1) (Thamlikitkul et al) compared fresh aloe mucilage with silver sulfadiazine cream, while the other Thai study( n2) (Visuthikosol et al) compared petroleum jelly gauze alone with gauze saturated with 85% aloe gel. The Indian study( n3) (Akhtar et al) compared aloe cream with framycetin cream. The Chinese study( n4) (Sun et al) compared petroleum jelly gauze alone with 1% aloe powder wrapped with petroleum jelly gauze. None of the studies reported the amount of key active ingredients of aloe gel in the products.(*)
All but 4 of the 371 patients in the 4 studies suffered thermal burns (the 4 had electrical burns). The severity of the burns and the percentage of the body surface area affected by the burns varied across the studies.
In two of the studies,( n2, n3) wound-healing time was used as the outcome measure. The authors report that a meta-analysis of those 2 studies showed that the healing time of the aloe group was 8.79 days shorter than that of the control group (P=0.006).
In the other 2 studies,( n1, n4) the outcome measures were the percentage of the success rate of wound healing and the rate of epithelialization, measured by the healing size, respectively. (Note: Epithelialization is the growth of tissue on a denuded surface.) In the Thamlikitkul study, the aloe group reported a 95% success rate of wound healing, while the silver sulfadiazine group reported an 83% success rate. The Chinese study reported that the epithelialization rate of burns for those in the group that used aloe with petroleum jelly gauze was higher than the group that used petroleum jelly only on day 5 and day 8 after skin grafting.
According to the authors, a major limitation of this study is possible measurement bias. All patients in two of the studies were evaluated by clinicians who were not blinded.
Referring to the existing evidence, the authors suggest that aloe gel used in various dosage forms might help accelerate the wound-healing process and increase the rate of success of healing, as well as the rate of epithelialization, in first- and second-degree burns when compared with conventional treatments. However, they also write that the differences in products used and outcome measures used make it difficult to draw a specific conclusion on the effect of aloe gel on burn wound healing. Further well-designed trials with sufficient details of the contents of aloe products are needed.
(*) A reviewer of this article provided the following comment regarding the contents of various aloe gel preparations: Almost no publications provide information as to the "quality" of the aloe product referred to in the respective research. The International Aloe Science Council uses (a) total solids, (b) calcium, (c) magnesium, and ( 4) malic acid concentrations in its aloe quality certification program. These factors were used as criteria because they are the least affected by soil conditions, season of harvesting, rainfall amounts, etc. (i.e., the numerous variables that affect the chemical constituents in any cultivated or wild-harvested plant used for economic, particularly medicinal, purposes). In the reviewer's laboratory, researchers add Size-Exclusion Chromatography to indicate the molecular sizing and quantities of all constituents, proton-nuclear magnetic resonance profiles, and, for wound-healing materials, the level of Insulinlike Growth Factor-11, and mannose-6-phosphate, the putative factors responsible for the healing of wounds.
PHOTO (COLOR): Aloe Aloe vera Photo © 2007 Steven Foster
(n1.) Thamlikitkul V, Bunyapraphatsara N, Riewpaiboon W, et al. Clinical trial of aloe vera Linn. for treatment of minor burns. Siriraj Hosp Gaz. 1991;43(5):313-316.
(n2.) Visuthikosol V, Sukwanarat Y, Chowchuen B, Sriurairatana S, Boonpucknavig V. Effect of aloe vera gel to healing of burn wound a clinical and histologic study. J Med Assoc Thai. 1995;78(8):403-408.
(n3.) Akhtar MA, Hatwar SK. Efficacy of aloe vera extract cream in management of burn wound. J Clin Epidemiol. 1996;49(Suppl 1):24.
(n4.) Sun JH, Chen XG, Jin RT, Li TN, Bian YX. People's Liberation Army medicine information. Med J Chin Army. 1994;8(4):191-192.
By Shari Henson