Aloe vera

Common name: Aloe vera
Other names: Aloe, cape, Zanzibar, curacao, burn plant, barbaos aloes, curalao, socotrine
Latin name: Aloe vera
Affinity: Digestive system, immune system
Actions: Cathartic (latex only), vulnerary, emmenagogue, vermifuge, external demulcent, immunomodulator, anti-inflammatory
Diseases: (Topical) Psoriasis(1), seborrheic dermatitis(1), heat and radiation induced burns(3), wound healing(2), posthemorrhoidectomy pain(1), oral lichen planus(1), acne vulgaris(1), chronic skin legions(2)/ (Internal) IBD(2), diarrhoea dominant IBS(2)
Parts used: Leaves

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Characteristics: Aloe vera is a stemless, perennial, drought-resistant, succulent plant of the lily family (Syed et al., 1996). The word ‘aloe’ comes from the Arabic, ‘alloeh’ meaning, ‘bitter and shiny’ which relates to the inner gel of the aloe vera leaf. Aloe vera yields gel, latex, and juice with different medicinal properties (Kuhn and Winston, 2000), this article is about the inner gel, as it is much better studied.

History: Aloe vera is indigenous to hot countries, it has been used as a medicine for over 5000 years by Egyptian, Indian, Chinese and European cultures (Langmead et al., 2004). Drawings of aloe vera have been found in Egyptian temples dating back to 3000BC Egyptian medical texts from 1500BC recommend aloe vera for infections, skin problems, and as a laxative. The Greek physician, Dioscorides, recommended aloe vera for wounds, haemorrhoids, ulcers, and hair loss. The Roman physician, Pliny, used it internally as a laxative. Later, Arab traders carried aloe from Spain to Asia in the 6th century. The traders introduced aloe vera to India’s Ayurvedic physicians, who used it to treat skin problems, intestinal worms, and menstrual discomforts. Traditional Chinese physicians used aloe vera in similar ways.

Current applications: Winston and Kuhn list topical aloe vera gel as useful for healing burns and reducing burn pain (Kuhn and Winston, 2000). This includes both heat related 1st and 2nd degree burns, but also radiation induced burns. They also point out, while there have been several negative studies, these studies often used a processed aloe vera gel containing various preservatives and stabilisers they believe may have negatively affected the medicinal properties of the extract. They also list it as useful in gastric ulcers, IBD, and where a cathartic (purgative) is required. The purgative properties are specifically from the latex not the gel, which is rarely used. Aloe vera gel may have a role in treating skin disorders where there is inflammation present such as psoriasis, acne, and oral lichen planus.

Science: Aloe vera gel extracts have been shown ex vivo and in vivo to display anti-inflammatory properties (Langmead et al., 2004; Vázquez et al., 1996). Aloe vera gel has been observed to decrease levels of prostaglandins ex vivo (Langmead et al., 2004), and also may repress the arachidonic acid pathway via cyclooxygenase in vivo (Vázquez et al., 1996). Studies using experimental models imply the gel may be useful in treating inflammatory disorders.

There is a high number of randomised double blind placebo controlled human clinical trials for aloe vera showing positive results against a range of disorders, mainly related to the skin and bowel. These trials are low powered, but the overall trends are convincing and in favour of genuine medicinal effects of aloe vera extracts. It is mainly the gel that has been studied which is extracted from the leaf, it has been shown to improve symptoms in patients with psoriasis (Syed et al., 1996), IBD (Langmead et al., 2004), oral lichen planus (Choonhakarn et al., 2008), and acne (Hajheydari et al., 2014). There is also reference to usage of a ‘cream’, overlapping terminology with ‘gel’, which has shown to be effective against seborrheic dermatitis (Vardy et al., 1999), posthemorrhoidectomy pain (Eshghi et al., 2010), and chronic skin legions (Panahi et al., 2012). These studies imply that aloe vera gel has a range of medicinal properties in humans and further larger studies are warranted.

Safety: Aloe vera stimulates uterine contractions so should be avoided during pregnancy, it also should be avoided during breast feeding. Otherwise it is safe if used appropriately.

Dosage: The gel may be applied 2 or 3 times daily to skin. For internal use, 100ml of gel has been applied twice daily for IBD, however, please see directions on the packaging or from your health care provider.

Brands: Aloe pura is one suitable supplier for a gel.

Scientific Summary

Research on models

Anti-inflammatory activity: An ex vivo study using human colorectal mucosa cells found an anti-inflammatory effect was induced by aloe vera gel (Langmead et al., 2004). Levels of prostaglandin were seen to decrease with application of aloe vera.

Anti-inflammatory activity(II): An in vivo study using experimental models found a reduction of inflammation with aloe vera treatment. Aqueous and chloroform extracts were superior to ethanolic. The authors concluded, extracts of Aloe vera gel have anti-inflammatory activity and this may occur through inhibitory action on the arachidonic acid pathway via cyclooxygenase.

Research on humans

Psoriasis: A study (n=60, double blind placebo controlled) found that treatment of patients with psoriasis who applied aloe vera extract 0.5% in a hydrophilic cream 3 times daily for up to 4 weeks experienced significant improvements compared with the placebo group (Syed et al., 1996).

Inflammatory bowel disease: One study (n=44, double blind placebo controlled) found that patients with IBD who took 100ml of an aloe vera gel twice daily for 4 weeks, in a 2:1 ratio, experienced greater relief than the placebo group, but the effects were either not quite significant or not very significant (Langmead et al., 2004). The authors concluded that treatment appeared safe and further studies were warranted to confirm the positive medicinal action of aloe vera on IBD they observed.

Seborrheic dermatitis: A study (n=44, double blind placebo controlled) discovered a cream of aloe vera applied onto the skin (twice daily over 4-6 weeks) resulted in a significant reduction in the symptoms of seborrheic dermatitis compared with the placebo only group (Vardy et al., 1999).

Irritable bowel syndrome: One study (n=49, double blind placebo controlled) found an aloe vera formulation taken at a dose of 50ml four times daily did not significantly improve IBS symptoms, however, they noted near significant trends particularly in diarrhoea dominant IBS towards improvement (Davis et al., 2006). It is not clear from the paper what exactly this aloe vera formulation was, except, it was prepared by a company called Natural Living Products.

Posthemorrhoidectomy pain: A study (n=49, double blind placebo controlled) found that aloe vera cream when applied to the post-operative site after hemorrhoidetomy significantly reduced pain and increased wound healing compared with the placebo only group (Eshghi et al., 2010). The cream was applied to the surgical site 3 times per day for 4 weeks after hemorrhoidectomy. The cream was made from aloe vera powder in a special protocol.

Oral lichen planus: A study (n=54, double blind placebo controlled) reported that aloe vera gel when applied twice daily in patients with oral lichen planus significantly reduced the symptoms of this disease when applied over 8 weeks (Choonhakarn et al., 2008).

Acne vulgaris: One study (n=60, double blind alternative medication controlled) found that treatment with tretinoin and aloe vera gel was superior to tretinoin alone in the treatment of acne vulgaris (Hajheydari et al., 2014). Tretinoin was applied in the evening, while aloe vera gel was applied morning and evening.

Chronic skin legions: A study (n=63, double blind alternate medication controlled) reported that aloe vera and olive oil cream was as effective as the drug betamethasone in treating chronic skin legions in war veterans that had been exposed to sulfur mustard (Panahi et al., 2012). The study was conducted over 6 weeks and the cream was applied 2 times daily. They also found fissure and excoriation improved better in the aloe vera group, but both treatment groups can comparable endpoints. A slight weakness in this study is there was no placebo group to compare the drug and aloe vera cream with.

References:

Choonhakarn, C., et al. “The efficacy of aloe vera gel in the treatment of oral lichen planus: a randomized controlled trial.” British journal of dermatology 158.3 (2008): 573-577.

Davis, K., et al. “Randomised double‐blind placebo‐controlled trial of aloe vera for irritable bowel syndrome.” International journal of clinical practice 60.9 (2006): 1080-1086.

Eshghi, Fariborz, et al. “Effects of Aloe vera cream on posthemorrhoidectomy pain and wound healing: results of a randomized, blind, placebo-control study.” The Journal of Alternative and Complementary Medicine 16.6 (2010): 647-650.

Hajheydari, Zohreh, et al. “Effect of Aloe vera topical gel combined with tretinoin in treatment of mild and moderate acne vulgaris: a randomized, double-blind, prospective trial.” Journal of Dermatological Treatment 25.2 (2014): 123-129.

Kuhn, Merrily A., and David Winston. Herbal therapy and supplements: a scientific and traditional approach. Lippincott Williams & Wilkins, 2000.

Langmead, L., et al. “Randomized, double‐blind, placebo‐controlled trial of oral aloe vera gel for active ulcerative colitis.” Alimentary pharmacology & therapeutics 19.7 (2004): 739-747.

Langmead, L., R. J. Makins, and D. S. Rampton. “Anti‐inflammatory effects of aloe vera gel in human colorectal mucosa in vitro.” Alimentary pharmacology & therapeutics 19.5 (2004): 521-527.

Panahi, Yunes, et al. “Efficacy of Aloe vera/olive oil cream versus betamethasone cream for chronic skin lesions following sulfur mustard exposure: a randomized double-blind clinical trial.” Cutaneous and ocular toxicology 31.2 (2012): 95-103.

Syed, Tanweer A., et al. “Management of psoriasis with Aloe vera extract in a hydrophilic cream: a placebo‐controlled, double‐blind study.” Tropical Medicine & International Health 1.4 (1996): 505-509.

Vardy, D. A., et al. “A double-blind, placebo-controlled trial of an Aloe vera (A. barbadensis) emulsion in the treatment of seborrheic dermatitis.” Journal of dermatological treatment 10.1 (1999): 7-11.

Vázquez, Beatriz, et al. “Antiinflammatory activity of extracts from Aloe vera gel.” Journal of ethnopharmacology 55.1 (1996): 69-75.