Aloe vera has been tested against a variety of infections, viral, bacterial and fungal. The exudate of Aloe (aloin) has been confirmed again and again as having direct anti-microbial effects, killing invading pathological organisms. However the principal benefits of Aloe with regard to infective agents comes from aloin-free or de-aloinized extracts, which work by strengthening the body’s own defences. This newsletter closely examines these functions of Aloe.
The point has already been made in Newsletter No1 that Aloe, by supporting and stimulating the immune system, greatly augments the ability of the body to resist bacterial and viral infections. This point was made in relation to such Aloe products as Gel and Whole Leaf Extract which contain the glucomannan of Aloe and in which the exudate fraction of Aloe (“Aloin”, or “Phenolic” fraction) is only present in very low concentrations or has been removed in processing. It must be emphasized that when Aloe is used in this way, the effect being exerted upon the invading organisms is indirect. The glucomannan is, in itself, by no means capable of killing micro-organisms and can only produce an indirect effect by stimulating the immune system to destroy them. Indeed, glucomannan is almost certainly vulnerable to bacterial degradation itself and will not survive a bacterial fermentation of the Aloe extract containing it.
On the other hand, the components of the “Aloin”, or “Phenolic” fraction have been shown, through quite a number of studies, to have a direct destructive action upon bacteria. We therefore have two ways in which these differing components of Aloe may act against bacteria and as it is important for the reader to draw this distinction clearly in the mind, this is represented diagrammatically below.
direct killing action
Aloe Exudate —————–> Bacteria
stimulation immune attack
Aloe Glucomannan —————–> Immune System —————–> Bacteria
One can only distinguish between these two effect in studies in which the Exudate compounds and the glucomannan components of Aloe have been effectively separated. In any studies with Aloe arborescens the Whole Leaf Extract is usually used, and similarly, if Aloe vera Whole Leaf Extract is used without carbon filtration, both the Exudate materials and the glucomannan are present together and their actions cannot be distinguished. This seems to be most often the case with Japanese work on the anti-bacterial effects of Aloe are investigated, where species other than vera are usually employed, especially Whole Leaf Extracts of Aloe arborescens.
Some work reported in the literature omits to make it perfectly clear whether the Aloe preparations being studied contain Exudate or glucomannan or both. This is true of the work of Heggers et al (1979), in which clear anti-microbial effects are reported.
To help the reader conceptualize the microorganisms involved in infections, suitable illustrations of bacteria and viruses are provided amongst the text.
The Bacteriostatic / Bacteriocidal effects of Aloe Exudate
Lorenzetti et al, in 1964, tested leaves of Aloe vera for activity against several bacterial types. The material used was the Exudate fraction, that is to say, they cut the leaves and allowed the juice to drain out. This material was effective against Staphylococcus aureus – an organism present in purulent discharges – but only when it was quite fresh, or when steps were taken to preserve it by heating (presumably to inactivate enzymes that were destroying the activity) followed by freeze-drying. Some species of the bacterial genera Salmonella, Streptococcus, Staphylococcus and Corynebacterium were inhibited by these freeze-dried extracts, though some other species of the same genera were not inhibited.
Bruce, in 1967, also did tests for anti-bacterial activity on the Exudate of Aloe vera. The results showed considerable activity against gram-positive bacteria and against human tubercle bacillus – the organism of tuberculosis. The results with Aloe vera showed more anti-bacteria! activity than with other species of Aloe and was detectable even when the juice was diluted 1,600 fold. This work appeared to show, not surprisingly that the anthraquinone compounds in the juice had the greatest antibacterial, activity.
Haraguchi et al (1992), in a paper entitled “Actionmode of Anti-microbial Aitersolanol A on Pseudomonas aeruginosa”, demonstrated that an anthraquinone-type antibiotic interferes with the respiratory chain of the bacterium causing its death by the disruption of its energy sources.
This seems to have been the first clear indication of just how the Aloe Exudate materials may work on the bacteria.
Anti-fungal effects of Aloe vera Exudate
Work such as that of Soeda, in two papers, both dated 1966, clearly indicates that the Exudate fraction of Aloe, or Leaf Extracts containing the Exudate materials, also have anti-fungal action.
Increased Resistance to Bacterial Infections after treatment with Aloe Gel or Whole Leaf
Most of the work on this subject has been done using Aloe vera Gel, since that has been most widely available in the recent past until Whole Leaf became available. Some of the work did not draw a clear distinction between direct bacteriocidal effect on the one hand and the immune-mediated effect on the other. This was possibly true with the work of Cheney in 1970 and of Robson et al in 1980.
This was concerned with putting Aloe Gel onto burns and studying whether the organism which most often infects burn tissues, Pseudomonas aeruginosa, was inhibited. Cheney’s results were negative and those of Robson were positive, but in this particular situation there is no way to distinguish between a direct bacteriocidal action and an immune mediated response. Cera et al (1980) also found that there was inhibition of Pseudomonas aeruginosa in the burn tissues of the skin of dogs.
Based upon other studies with Aloe vera Gel, and the fact that the Gel is readily fermented and spoiled by bacterial growth if not Pasteurized and treated with preservatives, its direct bacteriocidal properties do not appear at all strong. Most of the other work with Gel or Whole Leaf Extract makes it clear that an immune mediated is usually involved.
Northway, in 1975, used a commercial extract of Aloe vera Gel in his veterinary practice to treat a number of external conditions in a total of 67 animals. Part of his conclusion was that there was excellent response in the case of fungal infections and also “in the treatment of mixed bacterial infections”.
Solar et al. (1979), of I’Institut Pasteur de Madagascar, wrote a paper entitled “Mise en evidence étude propriétés immunostimulantes d’un extrait isole et partiellement purifie a partir d’Aloe vahombe”. The extract, obtained from a species of Aloe other than Aloe vera, markedly increased the resistance of mice to Klebsiella pneumoniae, apparently through the effects on host physiology (by inference, the immune system), rather than an antibiotic or anti-septic effect.
Increased Resistance to Viral Infections after treatment with Aloe Gel or Whole Leaf Extract
There is no doubt that some of the most interesting work in this whole area relates to the way in which use of Aloe augments the body’s resistance to viral infections. Only a small amount of such work has been reported and, as is so often the case, it leaves one wishing that a great deal more work of this type could be done. The available reports relate to work on cats with the Feline Leukemia Virus (FeLV) and to human infection with AIDS. In some of this work the material used is referred to as “acemannan”. The reader is asked to accept this as a synonym for “glucomannan”. Really it is a trade name for isolated and dried glucomannan from Aloe.
The AIDS Virus
The work of Pulse & Uhlig, 1990, entitled “A Significant Improvement in A Clinical Pilot Utilizing Nutritional Supplements, Essential Fatty Acids And Stabilized Aloe vera Juice In 29 HIV Seropositive, ARC And AIDS Patients.” has shown that Aloe, together with the nutrients cited in the study, can be effective in improving the general health and immune status of AIDS patients. The trial lasted for 180 days and the 29 patients were assessed by medical examination and laboratory studies at 30, 60, 90 and 180 days after the start of the programme. They were also assessed by a Modified Walter Reed Clinical Evaluation. This showed that, according to that evaluation, all 29 patients improved by 90 days and 27 of them made further improvement by 180 days. The mean value decreased by two units from a starting value of 5.39, a considerable improvement. They were also assessed by the Karnofsky Quality of Life Assessment, in which the scores rose in 90 days from a mean of 78.97% at the start to 92.41% at the end (these results show improvement as they rise). It is noteworthy that by 180 days, not only had the mean values improved but 100% of the patients individually, had shown improvements. Clearly, it is not possible to separate out the effects due to the Aloe from the effects of the essential fatty acids and other nutrients employed in the study. However, Practitioners will be quick to note that the use of Aloe along with nutritional supplementation is exactly what should be recommended, since Aloe itself is not primarily taken for its nutrient content and its use, logically, should never exclude or diminish the simultaneous use of nutritional supplements.
This very positive result is not unexpected in view of Aloe’s proven powers of general enhancement of the immune system. The use of natural immuno-stimulants for this purpose, rather than synthetic drugs, has long seemed obvious to wholistic practitioners. Clearly, much more work needs to be done. In this connection it is good to note from an Editorial in “Inside Aloe” that a moderate-sized organised trial of Aloe vera against AIDS is planned at The South West College of Naturopathic Medicine and Health Sciences in Arizona, U.S.A. A paper was presented on this at the July 1996 Meeting of the International Aloe Science Council by Dr. A. Schauss and Dr. I. Bier and it does appear that there is a real opportunity here to obtain better and fuller information about the effects of Aloe upon AIDS. There is certainly a fair amount of testimonial evidence in favour of the use of Aloe vera in AIDS, especially that offered by Ritter, 1991, Ritter, 1993.
These findings are backed up by some in vitro work (i.e. work on surviving tissues cells outside of the body in tissue culture) by Kahlon et al, 1991, entitled “Inhibition Of Aids Virus Replication By Acemannan In Vitro”. White blood cells (mononuclear cells and T4 lymphocytes) were used in the experiment as “targets” for the virus attack. Exposure to the glucomannan of Aloe showed that it offered a degree of protection to the blood cells from attack. The replication of the virus was slowed down and there was a decrease in the infectivity of the viral progeny. The same thing was observed with Newcastle disease virus and the Herpes simplex virus.