Scientists employ mango, mushroom to beat cancer

CAN meals rich in mangoes and edible mushroom help to prevent or/and stop the spread of cancers? Mangoes and mushrooms have been discovered to contain ingredients that could be used for the production of new drugs for the treatment of cancers.

Scientists have discovered how a promising cancer drug, first discovered in a wild mushroom, works. The University of Nottingham, United Kingdom, team believe their work could help make the drug more effective, and useful for treating a wider range of cancers.

Cordycepin, commonly used in Chinese medicine, was originally extracted from a rare kind of parasitic mushroom that grows on caterpillars. The study appeared in the Journal of Biological Chemistry.

Also, mango has been found to prevent or stop certain colon and breast cancer cells in the laboratory. A new study by Texas AgriLife Research food scientists, United States, who examined the five varieties most common in the U.S.- Kent, Francine, Ataulfo, Tommy/Atkins and Haden- found some impact on lung, leukemia and prostate cancers but was most effective on the most common breast and colon cancers.

Mango is botanically called Mangifera indica and belongs to the plant family Anacardiaceae. Mango is mangoro (the fruit), mangorohi (the tree) in Fula-Fulfulde; umangohi in Idoma; mangolo in Igala; mangulo in Igbo; and mangoro or oro oyinbo in Yoruba.

Nigerian researchers have also determined the protein content of three wild mushroom species growing in Owo Local Government areas of Ondo State: Termitomyces robustus (known as Ewe in Yoruba), Lentinus squarrosulus Mont (known as Tifa in Yoruba) and Lentimula edodes (known as Sheshe-Ope in Yoruba).

According to the result of the study published in Ethnobotanical Leaflets and Plant Foods for Human Nutrition (formerly Qualitas Plantarum), the highest amount of protein was found in Lentinus squarrosulus Mont (37.80mg/ml), followed by Termitomyces robustus (33.00mg/ml) and least found in Lentimula edodes (17.00mg/ml).

The researchers include: R. A. Jose of the Department of Science Technology, Rufus Giwa Polytechnic, Owo, Ondo State; and J. Kayode of the Department of Plant Science, University of Ado-Ekiti, Ado-Ekiti, Ekiti State.

Over the last decade, mushrooms have been studied as a novel functional food in Japan, Korea, China and Taiwan. Mushrooms, which have been used as food from time immemorial for their taste and flavour, have in recent times been found to be highly nutritious and medicinal. They are rich in high quality protein, minerals and vitamins such as folic acid but low in fat content.

In Nigeria, wild edible mushrooms are one of the important minor forest products, which are locally traded in local market of the country. Due to their high content of protein, vitamins and minerals, mushrooms are considered as "poor man's protein".

Previous studies had asserted that the maximum protein content and the best amino acid balance are found in mushrooms just before the caps expand. It has also been established that the major food value of mushroom lies in their protein components.

The results of the Ondo State study revealed that these mushrooms are nutritiously good for consumption. In fact, previous studies had revealed that edible mushrooms contained all the essential amino acids as well as most commonly occurring non-essential amino acids and amides.

The study found that mushrooms are low in calories, have no cholesterol and are virtually free of fat and sodium. Mushrooms also contain other essential minerals like selenium, which works with vitamin E to produce antioxidants that neutralise "free radicals" which can cause cell damage.

Studies have suggested that selenium may reduce the risk of cancer, cardiovascular disease, it may slow the progress of Human Immuno-deficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS) disease and may aid in symptoms of rheumatoid arthritis, pancreatitis and asthma. Studies show men who eat selenium rich foods may lower their risk of prostate cancer.

Potassium, which is widely reputed for being good for the heart, is also found in mushrooms. It has been suggested that a diet with potassium may help to reduce the risk of high blood pressure and stroke.

Copper is another essential mineral found in mushrooms. Copper aids iron, which is also known for making red blood cells and delivers oxygen to the body.

Mushrooms also contain three B-Complex vitamins; riboflavin for healthy skin and vision, niacin that aids the digestive and nervous systems, and pantothetic acid which helps the nervous system and hormone productions.

Previous studies have suggested that mango possess anti-inflammatory, analgesic and hypoglycemic (lowers blood sugar) effects in man and mammalian experimental animals.

Researchers had confirmed the anti-inflammatory, analgesic and anti-diabetic properties of the stem-bark aqueous extract of mango in rats and mice.

An aqueous decoction of mango stem bark (MSB) has been developed in Cuba on an industrial scale to be used as a nutritional supplement, cosmetic, and phytomedicine, with antioxidant, anti-inflammatory, analgesic, and immunomodulatory properties.

In another study, flavonoids from mango effectively reduce lipid levels in serum and tissues of rats induced hyperlipidemia (high blood lipids/fats).

Researchers have also shown the protective effect of mango polyphenols on human T lymphocytes (white blood cells) against activation-induced cell death. The aqueous stem bark extract of mango (Vimang) has been reported to have antioxidant properties and prevents cell death in HIV/AIDS.

Researchers suggest that the different chemical constituents of the plant, especially the polyphenolics, flavonoids, triterpenoids, mangiferin, and other chemical compounds present in the plant may be involved in the observed anti-inflammatory, analgesic, and hypoglycemic effects of the plant's extract.

Also known as "Chinese caterpillar mushroom", "Semitake" and "JinShuBao", the cordyceps mushroom (usually the cordyceps sinensis variety) has been used in Chinese medicine for many centuries to make lung and kidney tonics.

The cordyceps mushroom gained fame when Chinese Olympic athletes in 1992 credited their successes to taking the mushroom as a supplement.

However, although the mushroom-based drug showed great promise, it was quickly degraded in the body. It can be given with another drug to combat this - but the second drug can produce side effects that limit its potential use.

As a result, researchers turned their interest to other potential candidate drugs, and exactly how cordycepin worked on the body's cells remained unclear.

Researcher Dr Cornelia de Moor said: "Our discovery will open up the possibility of investigating the range of different cancers that could be treated with cordycepin. It will be possible to predict what types of cancers might be sensitive and what other cancer drugs it may effectively combine with. It could also lay the groundwork for the design of new cancer drugs that work on the same principle."

The researchers have also developed a method to test how effective the drug is in new preparations, and combinations with other drugs, which might solve the problem of degradation more satisfactorily.

De Moor said: "This is a great advantage as it will allow us to rule out any non-runners before anyone considers testing them in animals."

The Nottingham team observed two effects on the cells - at a low dose cordycepin inhibits the uncontrolled growth and division of the cells, and at high doses it stops cells from sticking together, which also inhibits growth.

Both of these effects probably have the same underlying mechanism - that cordycepin interferes with how cells make proteins.

At low doses cordycepin interferes with the production of mRNA, the molecule that gives instructions on how to assemble a protein. And at higher doses it has a direct impact on the making of proteins.

In Chinese medicine, cordyceps has been used primarily to treat lung problems, specifically given when patients cough up blood or show other signs of lung inflammation.

A study by Taiwanese researchers showed cordyceps could be used to reduce lung inflammation in mice with symptoms of asthma. While cordyceps did not prove as effective as two other agents (including prednisolone, which is the active ingredient in several anti-asthma medications but whose side-effects can be as serious as inducing diabetes), the scientists did show cordyceps could indeed be used for lung problems.

Korean researchers showed that cordyceps is a great help in blocking the expression of rheumatoid arthritis. It potently blocked various chemicals that trigger rheumatoid arthritis.

More promising than its use in fighting inflammatory problems is its potential as a cancer-fighting agent. Like other medicinal mushrooms, the cordyceps mushroom contains a high concentration of polysaccharides.

Polysaccharides are molecules that have cancer-fighting properties; numerous studies have shown that polysaccharide-rich compounds inhibit the growth of cancerous tumours in lab animals.

Certain types of cordyceps have polysaccharides containing selenium, a chemical element that is toxic in large amounts, but trace amounts of selenium are necessary for cellular health. Selenium also forms the active centers of certain enzymes which act as anti-oxidants. Anti-oxidants prevent cell damage caused by unstable molecules, or "free radicals", and cells damaged by free radicals are one of the causes of cancer.

Chinese researchers exploring the selenium-rich polysaccharides from certain types of cordyceps in tumor-bearing lab mice found that cordyceps showed "significant anti-tumor action with the inhibitory rate of 46.92 per cent.

Meanwhile, Korean researchers discovered that an aqueous extract of the same species of cordyceps (cordyceps militaris) could also be used to kill human breast cancer cells. The cordyceps mushroom has been studied by medical researchers for some time - the first scientific publication on cordycepin was in 1950.

Cordyceps is not as well researched as Reishi but Cancer Research United Kingdom suggests that, 'Cordyceps may be useful for cancer patients due to its enhancement of cell-mediated immunity, oxygen free radical scavenging and support for cellular bioenergy systems'.

Medicinal mushrooms have latent cancer preventative properties. Studies in Japan and Brazil strongly suggest that regular consumption over prolonged periods significantly reduce the levels of cancer incidence.

Cancer Research UK also found increasing experimental evidence that medicinal mushrooms can have a cancer preventative effect, demonstrating both high anti-tumor activity and restriction of tumor metastasis. A 14-year survey in Japan revealed cancer rates of workers at medicinal mushroom farms were one in 1000 compared to one in 600 for the general population.

Professor Janet Allen is director of research at the Biotechnology and Biological Sciences Research Council, which funded the mango study.

She said: "This project shows that we can always return to asking questions about the fundamental biology of something in order to refine the solution or resolve unanswered questions. The knowledge generated by this research demonstrates the mechanisms of drug action and could have an impact on one of the most important challenges to health."

Though the mango is an ancient fruit heavily consumed in many parts of the world, little has been known about its health aspects. The National Mango Board commissioned a variety of studies with several U.S. researchers to help determine its nutritional value.

Dr. Susanne Talcott, who with her husband, Dr. Steve Talcott, conducted the study on cancer cells said: "If you look at what people currently perceive as a superfood, people think of high antioxidant capacity, and mango is not quite there. In comparison with antioxidants in blueberry, acai and pomegranate, it's not even close."

Talcott noted: "But the team checked mango against cancer cells anyway, and found it prevented or stopped cancer growth in certain breast and colon cell lines.

"It has about four to five times less antioxidant capacity than an average wine grape, and it still holds up fairly well in anticancer activity. If you look at it from the physiological and nutritional standpoint, taking everything together, it would be a high-ranking super food. It would be good to include mangoes as part of the regular diet."

The Talcotts tested mango polyphenol extracts in vitro on colon, breast, lung, leukemia and prostate cancers. Polyphenols are natural substances in plants and are associated with a variety of compounds known to promote good health.

Talcotts said: "Mango showed some impact on lung, leukemia and prostate cancers but was most effective on the most common breast and colon cancers. What we found is that not all cell lines are sensitive to the same extent to an anticancer agent.

"But the breast and colon cancer lines underwent apotosis, or programmed cell death. Additionally, we found that when we tested normal colon cells side by side with the colon cancer cells, that the mango polyphenolics did not harm the normal cells."

The duo did further tests on the colon cancer lines because a mango contains both small molecules that are readily absorbed and larger molecules that would not be absorbed and thus remain present in a colon.

She said: "We found the normal cells weren't killed, so mango is not expected to be damaging in the body. That is a general observation for any natural agent, that they target cancer cells and leave the healthy cells alone, in reasonable concentrations at least."

The Talcotts evaluated polyphenolics, and more specifically gallotannins as being the class of bioactive compounds (responsible for preventing or stopping cancer cells). Tannins are polyphenols that are often bitter or drying and found in such common foods as grape seed, wine and tea.

The study found that the cell cycle, which is the division cells go through, was interrupted. This is crucial information, Suzanne Talcott said, because it indicates a possible mechanism for how the cancer cells are prevented or stopped.

Talcotts said: "For cells that may be on the verge of mutating or being damaged, mango polyphenolics prevent this kind of damage. From there, if there is any proven efficacy, then we would do a larger trial to see if there is any clinical relevance."

The Talcotts hope to do a small clinical trial with individuals who have increased inflammation in their intestines with a higher risk for cancer.

According to The Useful Plants of Tropical West Africa by H. M. Burkill, the bark has astringent properties. A macerate is widely taken for diarrhoea and dysentery in Senegal, Ivory Coast, Nigeria and Congo. In Ivory Coast, a decoction is used as a wash for the head in migraine, and is widely used as a mouth-wash for the relief of toothache, sore gums, sore-throat, etc. in Nigeria, and in Congo. This is taken in Ivory Coast as a diuretic against urethra discharge.

A.S. Daba and O.U. Ezeronye of the Division of Medical Biochemistry, Molecular Biology Laboratory, Faculty of Health Sciences, University of Cape Town, Observatory Cape Town, South Africa, have evaluated the anti-tumor activity of mushroom fruit bodies and mycelial extracts using different cancer cell lines.

The study is titled: "Anti-cancer effect of polysaccharides isolated from

higher basidiomycetes mushrooms."

According to the study published in Minireview, these polysaccharide extracts showed potent antitumor activity against sarcoma 180, mammary adenocarcinoma 755, leukemia L-1210 and a host of other tumors. The antitumor activity was mainly due to indirect host mediated immunotherapeutic effect. These studies are still in progress in many laboratories and the role of the polysaccharides as immunopoten

tiators is especially under intense debate.

Indeed, recent investigations has been channeled on the development of

immunotherapy to target and remove cancer cells as well as on substances such as immunopotentiators, immunoinitiators and biological response modulators

(BRM) that act to prevent carcinogenesis and induce carcinostasis. Mushrooms belong to this group of immunoceuticals by their mode of action.

The researchers wrote: "Mushroom polysaccharides offer a lot of hope for cancer patients and sufferers of many devastating diseases. A fundamental principle in oriental medicine is to regulate homeostasis of the whole body and to bring the disease person to his or her normal state.

"A variety of polysaccharides from a number of mushroom varieties have been demonstrated to enhance the immune system. All of these have shown significant

antitumour activity as a result of their ability to activate the host immune system rather than direct cytotoxicity. The mushroom polysaccharides appear to be well tolerated and compatible with chemotherapy and radiation therapy.

"However, studies that identifies the molecular mechanisms that occur in specific immune modulation by mushroom polysaccharides such as receptors and what downstream events are triggered by the binding of these polymers to their target cells are urgently needed."

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