14/05/2009 10:43

Moringa Disease Treatment and Prevention

 Disease Treatment and Prevention

The benefits for the treatment or prevention of disease or infection that may accrue from either dietary or topical administration of Moringa preparations (e.g. extracts, decoctions, poultices, creams, oils, emollients, salves, powders, porridges) are not quite so well known (116).

Diabetes - An extract from the Moringa leaf has been shown to be effective in lowering blood sugar levels within 3 hours of ingestion, though less effectively than the standard hypoglycemic drug, glibenclamide. The effects increased with larger doses.

Skin Treatment - Moringa has great healing benefits for the skin, curing cuts, scrapes, sores, and rashes as well as cracking and other signs of aging.


Although the oral history here is also voluminous, it has been subject to much less intense scientific scrutiny, and it is useful to review the claims that have been made and to assess the quality of evidence available for the more well-documented claims. The readers of this review are encouraged to examine two recent papers that do an excellent job of contrasting the dilemma of balancing evidence from complementary and alternative medicine (e.g. traditional medicine, tribal lore, oral histories and anecdotes) with the burden of proof required in order to make sound scientific judgments on the efficacy of these traditional cures (138,154). Clearly much more research is justified, but just as clearly this will be a very fruitful field of endeavor for both basic and applied researchers over the next decade.

Widespread claims of the medicinal effectiveness of various Moringa tree preparations have encouraged Prof Louis De Bruin and others like another author and his colleagues at The Johns Hopkins University to further investigate some of these possibilities. A plethora of traditional medicine references attest to its curative power, and scientific validation of these popular uses is developing to support at least some of the claims. Moringa preparations have been cited in the scientific literature as having antibiotic, antitrypanosomal, hypotensive, antispasmodic, antiulcer, anti-inflammatory, hypocholesterolemic, and hypoglycemic activities, as well as having considerable efficacy in water purification by flocculation, sedimentation, antibiosis and even reduction of Schistosome cercariae titer (see Table 1).

Unfortunately, many of these reports of efficacy in human beings are not supported by placebo controlled, randomized clinical trials, nor have they been published in high visibility journals. For example, on the surface a report published almost 25 years ago (141) appears to establish Moringa as a powerful cure for urinary tract infection, but it provides the reader with no source of comparison (no control subjects). Thus, to the extent to which this is antithetical to Western medicine, Moringa has not yet been and will not be embraced by Western-trained medical practitioners for either its medicinal or nutritional properties.

In many cases, published in-vitro (cultured cells) and in-vivo (animal) trials do provide a degree of mechanistic support for some of the claims that have sprung from the traditional medicine lore. For example, numerous studies now point to the elevation of a variety of detoxication and antioxidant enzymes and biomarkers as a result of treatment with Moringa or with phytochemicals isolated from Moringa (39,40,76,131). I shall briefly introduce antibiosis and cancer prevention as just two examples of areas of Moringa research for which the existing scientific evidence appears to be particularly strong.

6.Cancer Prevention. Since Moringa species have long been recognized by folk medicine practitioners as having value in tumor therapy (61), we examined compounds [1] and [2] for their cancer preventive potential (39). Recently, [1] and the related compound [3] were shown to be potent inhibitors of phorbol ester (TPA)-induced Epstein-Barr virus early antigen activation in lymphoblastoid (Burkitt’s lymphoma) cells (57,104). In one of these studies, [3] also inhibited tumor promotion in a mouse two-stage DMBA-TPA tumor model (104). In an even more recent study, Bharali and colleagues have examined skin tumor prevention following ingestion of drumstick (Moringa seedpod) extracts (12). In this mouse model, which included appropriate positive and negative controls, a dramatic reduction in skin papillomas was demonstrated.

Thus, traditional practice has long suggested that cancer prevention and therapy may be achievable with native plants. Modern practitioners have used crude extracts and isolated bioactive compounds. The proof required by modern medicine has not been realized because neither the prevention of cancer nor the modification of relevant biomarkers of the protected state has been adequately demonstrated in human subjects. Does this mean that it doesn’t work? No. It may well work, but more rigorous study is required in order to achieve a level of proof required for full biomedical endorsement of Moringa as, in this case, a cancer preventative plant.


 

7.Antibiotic Activity. This is clearly the area in which the preponderance of evidence—both classical scientific and extensive anecdotal evidence—is overwhelming. The scientific evidence has now been available for over 50 years, although much of it is completely unknown to western scientists. In the late 1940’s and early 1950’s a team from the University of Bombay (BR Das), Travancore University (PA Kurup), and the Department of Biochemistry at the Indian Institute of Science in Bangalore (PLN Rao), identified a compound they called pterygospermin [4] a compound which they reported readily dissociated into two molecules of benzyl isothiocyanate [5] (23,24,25,26,77,78,79,80,81,108). Benzyl isothiocyanate was already understood at that time to have antimicrobial properties. This group not only identified pterygospermin, but performed extensive and elegant characterization of its mode of antimicrobial action in the mid 1950’s. (They identified the tree from which they isolated this substance as “Moringa pterygosperma,” now regarded as an archaic designation for “M. oleifera.”) Although others were to show that pterygospermin and extracts of the Moringa plants from which it was isolated were antibacterial against a variety of microbes, the identity of pterygospermin has since been challenged (34) as an artifact of isolation or structural determination.

Subsequent elegant and very thorough work, published in 1964 as a PhD thesis by Bennie Badgett (a student of the well known chemist Martin Ettlinger), identified a number of glyosylated derivatives of benzyl isothiocyanate [5] (e.g. compounds containing the 6-carbon simple sugar, rhamnose) (8). The identity of these compounds was not available in the refereed scientific literature until “re-discovered” 15 years later by Kjaer and co-workers (73). Seminal reports on the antibiotic activity of the primary rhamnosylated compound then followed, from U Eilert and colleagues in Braunschweig, Germany (33,34). They re-isolated and confirmed the identity of 4-(a-L-rhamnopyranosyloxy)benzyl glucosinolate [6] and its cognate isothiocyanate [2] and verified the activity of the latter compound against a wide range of bacteria and fungi.

Extensive field reports and ecological studies (see Table 1) forming part of a rich traditional medicine history, claim efficacy of leaf, seed, root, bark, and flowers against a variety of dermal and internal infections. Unfortunately, many of the reports of antibiotic efficacy in humans are not supported by placebo controlled, randomized clinical trials. Again, in keeping with Western medical prejudices, practitioners may not be expected to embrace Moringa for its antibiotic properties. In this case, however, the in-vitro (bacterial cultures) and observational studies provide a very plausible mechanistic underpinning for the plethora of efficacy claims that have accumulated over the years (see Table 1).

Aware of the reported antibiotic activity of [2], [5], and other isothiocyanates and plants containing them, we undertook to determine whether some of them were also active as antibiotics against Helicobacter pylori. This bacterium was not discovered until the mid-1980’s, a discovery for which the 2005 Nobel Prize in Medicine was just awarded. H. pylori is an omnipresent pathogen of human beings in medically underserved areas of the world, and amongst the poorest of poor populations worldwide. It is a major cause of gastritis, and of gastric and duodenal ulcers, and it is a major risk factor for gastric cancer (having been classified as a carcinogen by the W.H.O. in 1993). Cultures of H. pylori, it turned out, were extraordinarily susceptible to [2], and to a number of other isothiocyanates (37,60). These compounds had antibiotic activity against H. pylori at concentrations up to 1000-fold lower than those which had been used in earlier studies against a wide range of bacteria and fungi. The extension of this finding to human H. pylori infection is now being pursued in the clinic, and the prototypical isothiocyanate has already demonstrated some efficacy in pilot studies (49,168).

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