Aloe vera efficacy opens new applications

Used for millennia in cosmetics and personal-care products, this cactuslike plant is becoming vogue again with the focus on one of its actives, acemannan, being an effective immuno-stimulant. Mark J Tallon, PhD, investigates

As a desertlike plant, aloe vera (Aloe barbadensis) belongs to the Liliaceal family, of which about 360 species exist. Its active constituents include lignin, saponins, salicylic acids, minerals, vitamins and amino acids.1 Much of the referenced research relates to its application as a transdermal gel/ointment for cosmetics and/or healing of wounds. However, the evidence for its effectiveness over a wide variety of medicinal applications — including antidiabetic, renal stones, irritable bowel syndrome and gastric ulcers — is relatively untapped at the commercial level. The following overview will help bring you up to pace on the next drivers in the aloe market.

No more rolling stones According to the US National Institutes of Health in 2000, patients made 2.7 million visits to health-care providers, and more than 600,000 patients went to emergency rooms for kidney-stone problems.2 The bad news is these painful stones that lodge in the urinary tract have been on the rise for the past three decades. In a bid to enhance prevention and protection from these stones, researchers from Khon Kaen Universities Faculty of

Medicine in Thailand have been investigating the therapeutic effects of aloe.3

The investigators set out to explore three areas related to aloe vera, including the value of consuming aloe vera gel for preventing renal-stone formation. Thirteen healthy boys ages 9-13 were enrolled in the trial and ingested 100g of freshly prepared aloe gel twice a day for seven consecutive days. Urine was collected for 24 hours one day prior to taking the gel (day 0), days two and five of consumption, and day eight (one day after completion). The authors also measured those compounds that can lead to kidney-stone formation, including calcium, oxalate and calcium phosphate. Following urinary analysis, the calcium, oxalate and calcium phosphate were significantly increased. As such, the authors concluded the changes in chemical composition of urine after aloe gel consumption demonstrates its potential for preventing kidney-stone formation among children.

Antidiabetic compounds
Diabetes is becoming more common in the United States, with the number of diabetic Americans more than doubled (from 5.8 million in 1980 to 14.7 million in 2004).4 Although at present people aged 65 years or older account for almost 40 per cent of the population with diabetes, the huge upsurge in obesity-related insulin insensitivity (type 2 diabetes) may swing toward a younger demographic in the near future. The economic implications of obesity and diabetic health complications are astounding, and as such any potential natural therapeutic would be embraced.

In a recent study from Japan, the anti-hyperglycaemic effect of aloe vera gel and a number of isolated compounds from the gel were assessed.5 On the basis of spectroscopic data, these compounds were identified as lophenol, 24-methyl-lophenol, 24-ethyl-lophenol, cycloartanol and 24-methylene-cycloartanol. These five phytosterols were evaluated for their antihyperglycaemic effects in type 2 diabetic mice.

In the blood stream, red blood cells contain the oxygen-carrying compound haemoglobin. Glucose can attach to the haemoglobin to make a glycosylated haemoglobin called haemoglobin A1C or HbA1C. The more glucose in the blood, the more haemoglobin A1C or HbA1C will be present in the blood, and this was one of the main markers assessed in this study. Following treatment with these five phytosterols, significant decreases of 15-18 per cent in HbA1c levels were observed in mice. There was no difference between these phytosterols in their ability to reduce blood glucose when assessed individually.

Administration of beta-sitosterol did not reduce the blood-glucose levels in type 2 mice.5 After administration of the five phytosterols for 28 days, fasting blood-glucose levels decreased to approximately 64, 28, 47, 51 and 55 per cent of control levels, respectively. These findings suggest that Aloe vera gel and phytosterols derived from loe vera gel have a long-term blood-glucose level control effect and would be useful for treating type 2 diabetes mellitus.

IBS: a complex issue
Irritable bowel syndrome, or IBS, is a problem that affects mainly the bowel, also called the large intestine. The bowel is the part of the digestive system that makes and stores stool. IBS is a syndrome that embodies several symptoms including cramping, bloating, gas, diarrhoea and constipation. It has been reported IBS causes reduced quality of life to the same degree of impairment as congestive heart failure.6 Additionally, people with IBS are more likely to be unable to work and to have visited their doctor than the general population.7 The conditions generate a substantial workload in both primary and secondary care, leading to excessive social, financial and personal pressures and as such an effective therapy for IBS is vital.

In a study carried out at St Georges Hospital Medical School, London, UK, researchers assessed the proposed beneficial effects of aloe vera treatment for IBS.8 Patients with IBS were randomised to receive aloe vera or matching placebo for one month. Symptoms were assessed at baseline, one and three months. Of the 58 original patients enrolled, 49 completed the protocol to one month and 41 to three months.

Eleven of 31 (35 per cent) aloe vera patients and six of 27 (22 per cent) placebo patients responded at one month. Diarrhoea-predominant patients showed a trend toward a response to treatment at one month. Although there was no statistical evidence that aloe vera benefits patients with IBS, the possibility that improvement occurred in patients with diarrhoea or alternating IBS while taking aloe vera, based on the trend analysis, warrants further investigation in patients with diarrhoea-predominant IBS using a variety of dosing protocols.

The next anti-inflammatory
Continuing with the gut-health theme, the Faculty of Medicine at Chulalongkorn University, Thailand, compared the effects of aloe vera and the pharmaceutical sucralfate (which binds to hydrochloric acid in the stomach and acts like an acid buffer protecting cells) on gastric microcirculatory changes, cytokine levels and gastric-ulcer healing.9 Male rats were divided into four groups defined as group one (control), group two (gastric ulcer group without treatment), and groups three and four as gastric ulcer treatment groups with sucralfate or aloe vera.

On day one after induction of a gastric ulcer, the inflammatory markers (leukocytes adherence and TNF-alpha) were significantly reduced in the ulcer groups treated with sucralfate and aloe vera. On day eight, the leukocyte adherence and TNF-alpha levels were significantly lower in the sucralfate and aloe vera ulcer groups, as were ulcer size following histopathology examination. Following these exciting results, the study's lead investigators commented that aloe vera treatment can reduce leukocyte adherence (inflammation trigger) and TNF-alpha levels, thereby promoting gastric-ulcer healing. These findings provide a significant basis for the use of aloe vera as a treatment for gastric ulcers, from which human trials are needed.

For the functional-foods industry this may be the next ingredient bearing fruit
Can aloe grow?
Aloe vera in Sanskrit means goddess, and for the functional-foods industry this may be the next ingredient bearing fruit. New areas of aloe research and discovery not discussed above include enhancement of bioavailability, 10 growth-factor stimulation for skin healing and health, 11 and immunomodulation. 12 These studies are spearheading the current aloe vera science drive, which will potentially aid some exciting new product development in the coming years.

Further development in determining the most effective doses for medicinal and supportive nutrition is needed if these applications are to ever evolve as truly efficacious. However, the amalgamation of the papers above provides a strong base from which aloe vera manufacturers can not only market, but those IP chasers can utilise to springboard into applicable human clinical trials.

1. Atherton P. Aloe vera revisited. Br J Phytother 1998;4:176-83.
2. No author. Kidney and urologic diseases report. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). NIH Publication No 05—2495. 2004.
3. Kirdpon S, et al. Changes in urinary compositions among children after consuming prepared oral doses of aloe (Aloe vera Linn). J Med Assoc Thai 2006;89(8):1199-205.
4. No author. National diabetes surveillance system: data and trends. National Diabetes Surveillance System. 2005.
5. Tanaka M, et al. Identification of five phytosterols from Aloe vera gel as anti-diabetic compounds. Biol Pharm Bull 2006;29(7):1418-22.
6. Whitehead WE, et al. Impact of irritable bowel syndrome on quality of life. Dig Dis Sci 1996;41:2248—53.
7. Drossman DA, et al. US householder survey of functional gastrointestinal disorders. Prevalence, sociodemography, and health impact. Dig Dis Sci 1993;38:1569—80.
8. Davis K, et al. Randomised double-blind placebo-controlled trial of aloe vera for irritable bowel syndrome. Int J Clin Pract 2006;60(9):1080-6.
9. Eamlamnam K, et al. Effects of Aloe vera and sucralfate on gastric microcirculatory changes, cytokine levels and gastric ulcer healing in rats. World J Gastroenterol 2006;12(13):2034-9.
10. Vinson JA, et al. Effect of Aloe vera preparations on the human bioavailability of vitamins C and E. Phytomedicine 2005;12(10):760-5.
11. Chen XD, et al. Effect of Aloe coarse polysaccharide on cytokine secretion of keratinocytes in vitro. Zhongguo Zhong Yao Za Zhi 2005;30(24):1944-6.
12. Talmadge J, et al. Fractionation of Aloe vera L. inner gel, purification and molecular profiling of activity. Int Immunopharmacol 2004; 4(14):1757-73.

Mark J Tallon, PhD, is chief science officer of OxygeniX, a London-based consultancy firm specialising in claims substantiation, product development and technical writing.
Dr Tallon is also co-founder of Cr-Technologies, a raw-ingredients supplier.
Respond: [email protected]

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