How mango, pineapple extract reduces risk of diseases

[XXPANTHAXX]

June 19, 2008. Guardian. Lagos, Nigeria

Besides their popular use in treating malaria and digestive disorders, extracts of mango and pineapple have been found useful in diabetes, arthritis, HIV/AIDS, cancer, ulcer, among other diseases. CHUKWUMA MUANYA reports.

RESEARCHERS have shown that extracts of mango and pineapple can reduce the risk of developing degenerative diseases such as diabetes, bring relief in arthritis and cancer, and prevent cell death in Human Immuno-deficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS).

Mango is botanically called Mangifera indica and belongs to the plant family Anacardiaceae, while pineapple is Ananas comosus of the family Bromeliaceae.

In Nigeria, pineapple in Edo is (oil-palm tree of the white man) in Efik, onima (Westermann) in Fula-Fulfulde, brba from Akan in Hausa, nkwuaba (European palm-fruit) or akwu in Kanuri from Hausa, kp�cigb� (cough medicine) in Nupe, mbuer akporo in Tiv, (whiteman's plantain) or ope (whiteman's palm) in Yoruba.

Mango is called … in Edo; to the Efik it is; Fula-Fulfulde, mangoro (the fruit), mangorohi (the tree); Hausa, m…; Ibibio, m…; Idoma, umangohi; Igala, mangolo; Igbo, mangulo or Tiv, c..gh; and Yoruba mangoro or oro Oyinbo.

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

However, a recent study has confirmed the anti-inflammatory, analgesic and anti-diabetic properties of the stem-bark aqueous extract of mango in rats and mice.

Until now, the leaves of mango are used as an antidiabetic agent in Nigerian folk medicine. To determine whether or not there is a scientific basis for this use, researchers have assessed the effect of the aqueous extract of the leaves on blood glucose level in normoglycaemic (normal blood glucose level), glucose-induced hyperglycaemic (high blood glucose level) and streptozotocin (STZ)-induced diabetic rats.

The study is titled "Antihyperglycaemic effect of Mangifera indica in rat". The authors include A. O. Aderibigbe, T. S. Emudianughe, and A. S. Lawal of the Department of Pharmacology and Therapeutics, University of Ilorin and Department of Pharmacology, University of Calabar.

The leaves of Mangifera indica were assessed for antidiabetic properties using normoglycaemic, glucose-induced hyperglycaemia and streptozotocin (STZ) induced diabetic mice. The aqueous extract produced a reduction of blood glucose level in normoglycaemic and glucose-induced hyperglycaemia, but did not have any effect on streptozotocin-induced diabetic mice. The hypoglycaemic (lowers blood glucose) effect of the aqueous extract was compared with that of an oral dose of chlorpropamide (conventional blood glucose lowering drug) under the same conditions.

The aqueous extract given orally (1 g/kg) did not alter the blood glucose levels in either normoglycaemic or STZ-induced diabetic rats. In glucose-induced hyperglycaemia, however, antidiabetic activity was seen when the extract and glucose were administered simultaneously and also when the extract was given to the rats 60 minutes before the glucose.

The hypoglycaemic effect of the aqueous extract was compared with that of an oral dose of chlorpropamide (200 mg/kg) under the same conditions. The results of this study indicate that the aqueous extract of the leaves of mango possess hypoglycaemic activity.

When the ethanolic extracts of Lawsonia inermis leaves, Holarrhena antidysenterica bark, Swertia chirata whole plant and Mangifera indica bark were tested (in-vitro) for alpha-glucosidase inhibitory activity. M. indica extract was found to be the most potent.

An aqueous decoction of mango (Mangifera indica) 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 Emblica officinalis and Mangifera indica effectively reduce lipid levels in serum and tissues of rats induced hyperlipidemia.

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

The stem-bark powder of M. indica was Soxhlet extracted with distilled water and used. The analgesic effect of the plant's extract was evaluated by the hot-plate and acetic acid test models of pain in mice, while the anti-inflammatory and anti-diabetic effects of the stem-bark extract were investigated in rats, using fresh egg albumin-induced paw edema, and streptozotocin (STZ)-induced diabetes mellitus, respectively. STZ is used to induce experimental diabetes in animal models.

In the anti-inflammatory, anti-diabetic and analgesic study, morphine (MPN), diclofenac (DIC), and chlorpropamide were used respectively as reference analgesic, anti-inflammatory, and hypoglycemic agents for comparison.

M. indica stem-bark aqueous extract (MIE, 50-800 mg/kg i.p.) produced dose-dependent and significant analgesic effects against thermally and chemically induced nociceptive pain stimuli in mice. MIE (50-800 mg/kg i.p.) also significantly inhibited fresh egg albumin-induced paw edema, and caused significant hypoglycemic effects in rats.

The 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.

The results of this experimental animal study lend pharmacological credence to the suggested folkloric uses of the plant in the management and control of painful, arthritic and other inflammatory conditions, as well as in the management of adult-onset type 2 diabetes mellitus, in some rural African communities.

Mango has also been applied as a major component of a polyherbal composition for the treatment of viral infections. The composition includes an effective amount of plant extracts of Withania somnifera and Mangifera indica; and an extract of purified Shilaj, obtained from rock exudates. The polyherbal preparation has received a United States Patent WO 2006078424 20060727.

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.

Young callus bark is taken from the trunk to make an enema for piles in Ghana and is also given rectally as a stimulant in wasting disease. Sap from the bark is used in West Africa and in Gabon as an anti-syphilitic. An irritant oil extracted from this sap has been used in the treatment of syphilis. The sap in Gabon and in Senegal is considered saponific.

The bark also yields an oleo-resin, which in India is sometimes sold as gum arabic. It too is considered anti-syphilitic and good for dermal infections. Examination of a bark extract for activity against avian malaria showed no action. A yellow dye can be obtained from the bark. The leaves are astringent like the bark, and are widely used for dysentery and diarrhoea, and as a mouth-wash-gargle for toothache, sore-throat, among others.

A leaf-decoction is used in Gabon for asthma and bronchitis. In Ivory Coast, a decoction is considered febrifugal, and also in Nigeria. The leaf is used in Nigeria to treat skin-diseases, and laboratory tests confirm an action of Sarcina lutea and Staphylococcus aureus, but with no action on Gram negative organisms, nor on fungi. A resin is said to be the active substance. The bark, stem and fruits also exhibit bacteristatic action.

A decoction of leaves along with those of other plants is taken in Ivory Coast by draught for giddiness. Young tender leaves are eaten as a vegetable in Indonesia and the Philippines. They are a good source of ascorbic acid. In time of dearth the mature leaves have been fed to cattle in India. These leaves contain the glycoside mangiferine, which with prolonged feeding causes death. The leaves are however very palatable and young trees growing where there are cattle need to be protected. At one time, now forbidden by law, the production of peori dye (Indian yellow) was a commercial enterprise in India by its separation from the urine of cattle fed on mature leaves.

Recent studies suggest that a proteolytic enzymes derived from pineapple stem, Bromelian, used for years as a meat tenderizer, among other things, in the food industry, may offer a wide array of health benefits for humans, including use as a digestive aid, an anti-inflammatory and wound-healing agent, and to support cardiovascular and circulatory health.

Indeed, bromelain contains active substances that aid digestion and help reduce inflammation. Bromelain is useful in the treatment of a wide range of conditions, but it is particularly effective in relieving inflammation associated with infection and physical injuries.

Although studies show mixed results, bromelain supplements may reduce swelling, bruising, healing time, and pain following surgery and physical injuries. In fact an authoritative body in Germany called the Commission E (similar to the United States Food and Drug Administration) approved the use of bromelain for these purposes.

Some studies of animals indicate that bromelain (applied to the surface of the skin) may be useful in removing dead tissue from third-degree burns (particularly burns that go through all layers of the skin). This application has not yet been tested on people, but traditional and current day practices in Japan, Hawaii and Taiwan include use of topical bromelain to clean wounds and burns. Similarly, some clinicians may recommend this topical agent to reduce swelling from insect bites or stings.

Although not all experts agree, bromelain supplements may help suppress cough, reduce nasal mucus associated with sinusitis, and relieve the swelling and inflammation caused by hay fever. Bromelain is approved by the German Commission E for the treatment of sinus and nasal swelling following ear, nose, and throat surgery or trauma.

The protein-digesting enzymes found in bromelain help promote and maintain proper digestion and may relieve symptoms of stomach upset or heartburn, particularly when used in conjunction with other enzymes such as amylase (which digests starch) and lipase (which digests fat). Similarly, an animal study suggests that the antibacterial effects of bromelain may help to control diarrhoea caused by bacteria. Studies in people are needed.

Bromelain supplements may be as effective as some commonly used nonsteroidal anti-inflammatory (NSAID) medications (such as ibuprofen and diclofenac) for reducing pain associated with osteoarthritis. Similarly, preliminary studies suggest that bromelain may also help reduce the pain associated with rheumatoid arthritis. Plus, long-standing use of bromelain suggests that this enzyme may be helpful as part of the treatment for other connective tissue disorders including scleroderma (build up of tough scar-like tissue in the skin and, at times, internal organs), bursitis, and tendinitis.

Some scientific evidence from test tubes and animals suggests that bromelain can fight against infectious agents such as viruses and bacteria. Therefore, bromelain may prove a useful addition to conventional treatment of bronchitis, pneumonia, and urinary tract infections. More research is needed.

A decrease in the volume and purulence of sputum was reported with the use of bromelain in a clinical study of 124 patients hospitalised with chronic bronchitis, pneumonia, bronchopneumonia, bronchiectasis, or pulmonary abscesses.

Researchers have investigated hypolipidemic (lowers blood lipid/cholesterol levels) mechanisms of the ethanolic extract of pineapple leaves in mice and then determined its activities in related enzymes.

The results showed that pineapple leaves extract significantly inhibited the increase in serum triglycerides (part of the lipid profile, used to assess risk of heart disease and diabetes) by 40 percent in fructose-fed mice. In mice induced by alloxan (used to induce experimental diabetes in animals) and high-fat diets, serum total cholesterol remained at a high level (180 - 220 mg/dl) within seven days of removing high-fat diets but reached normal level (120 - 140 mg/dl) after pineapple leaves extract (0.40 g/kg per day) treatment.

Also, pineapple leaves extract significantly inhibited serum lipids from the increase in Triton WR-1339-induced hyperlipidemic (elevated cholesterol and triglyceride) mice. Triton WR1339, an inhibitor of Lipoprotein Lipase (LPL), decreases Vitamin E concentration in some tissues of rats by inhibiting its transport to liver.

Pineapple leaves extract selectively activated lipoprotein lipase (LPL) activity by 200 per cent - 400 per cent and significantly inhibited 3-hydroxyl-methyl glutaryl coenzyme A (HMGCoA) reductase activity by 20 per cent - 49 per cent in vitro. HMGCoA is the target of the widely available cholesterol lowering drugs: statins.

Furthermore, two months of fenofibrate (used to treat high cholesterol and high triglyceride levels) administration particularly increased mice liver weights while pineapple leaves extract had no effect.

Taken together, these results suggest that pineapple leaves extract will be a new potential natural product for the treatment of hyperlipidemia that exerts its actions through mechanisms of inhibiting HMGCoA reductase and activating LPL activities. Its action mechanisms differentiate from those with fibrates (are effective medications in lowering blood triglyceride levels to prevent heart disease) but may be partly similar to those with statins (reduce the blood cholesterol level. This helps to prevent heart disease, stroke, and related diseases in people at increased risk). It is hoped that pineapple leaves extract may serve as the adjuvant for fibrates.

Another study has investigated the effect of Mangifera indica flowers decoction, on the acute and subacute models of induced ulcer in mice and rats. A single oral administration of the aqueous decoction (AD) from M. indica up to a dose of 5 g/kg, p.o. did not produce any signs or symptom of toxicity in the treated animals. The oral pre-treatment with AD (250, 500 and 1000 mg/kg) in rats with gastric lesions induced by ethanol, decreased the gastric lesions from 89.0+/-6.71 (control group) to 9.25+/-2.75, 4.50+/-3.30 and 0, respectively.

Researchers have shown that ethanolic extracts of pineapple leaves (AC) enriched with phenols have hypoglycemic activity in diabetic rats. They investigated the effect of AC on insulin sensitivity in rats and HepG2. In high-fat diet-fed and low-dose streptozotozin-treated diabetic Wistar rats subjected to challenge with exogenous human insulin, AC treatment at an oral dose of 0.40 g/kg could significantly improve sensitivity to exogenous insulin. After a sub-acute treatment, AC also could inhibit the development of insulin resistance in high-fat diet-fed and low-dose streptozotozin-treated diabetic rats following the test of loss of tolbutamide-induced blood glucose lowering action.

For intravenous insulin/glucose infusion test, high-fat diet-fed and low-dose alloxan-treated Wistar rats were associated with insulin resistance, which was improved after AC or fenofibrate treatment. AC application inhibited the development of insulin resistance in HepG2 cells. The above animal models were well developed to simulate type 2 diabetes.

The researchers concluded: "Taken together, our results suggest that AC may improve insulin sensitivity in type 2 diabetes and could be developed into a new potential natural product for handling of insulin resistance in diabetic patients."

According to The Useful Plants of Tropical West Africa by H. M. Burkill, pineapple is a semi-woody, sprawling to erect stems to about 80 cm high, with a dense rosette of long narrow leaves, often saw-edged, the stem topped by a fleshy-syncarpellaceous fruit with a further crown of smaller leaves.

The plant is the source of the well-known pineapple fruit. It is thought to be originally from the Parana-Paraguay rivers, in an area of Brazil where several other related Ananas species occur.

The unripe fruit is purgative, diuretic, anthelmintic (drugs that expel parasitic worms from the body, by either stunning or killing them), expectorant (cough medicine) and aborifacient (induces abortion). It is taken in Nigeria as an emmenagogue (promotes or increases the menstrual flow), while the flowers are taken for the same effect in Gabon and in Guinea. It is also used in Guinea as a vermifuge (expels and kills internal parasites) especially against ascaris (round worm).

The unripe fruit is regarded in Guinea as good for bladder-troubles, and the root for dropsy, perhaps by causing a diuretic effect. Leaf-sap is administered, with powdered pimento added, as an enema in Ivory Coast for urethral discharge, while in Ghana immature fruits are taken for venereal disease. Juice from young fruit is taken in Congo for vertigo, and with Costus afer Ker-Gawl and salt it is used to wash small-pox sores.

Leaf-sap is considered in Gabon to be good for burns and wounds. In Sierra Leone, a warm infusion of the leaves has been reported good for fomenting a spider-bite, alternating the treatment with application of pieces of the fruit. The leaves, ground with copper or brass filings and palm-oil have been found effective in Ghana in healing ulcers.

Difficulty in breathing is treated in Congo by taking a root-decoction. Juice from a roasted fruit is made in Ghana into a thick gruel called flaku, which is given to children and sick persons. The fruit is rich in vitamin C, ascorbic acid being present at 24.4 to 96.3 mg per cent; it is present in the fresh young leaf also at 29.4 mg per cent.

The fruit, ripe and unripe, the leaves and the stalk all contain bromelin, a powerful proteolytic enzyme similar to papain found in Carica papaya (Caricaceae). It does not, however, coagulate milk as does papain. It is anthelmintic and is used in tropical America, Brazil and India. Alkaloid has also been reported in the fruit and root. There is a superstition in Ghana that a sick person near to death will express a great desire to eat pineapples.

Pineapple juice is taken as a diuretic and to expedite labor, also as a gargle in cases of sore throat and as an antidote for seasickness. The flesh of very young (toxic) fruits is deliberately ingested to achieve abortion (a little with honey on three successive mornings); also to expel intestinal worms; and as a drastic treatment for venereal diseases.

In Africa, the dried, powdered root is a remedy for edema. The crushed rind is applied on fractures and the rind decoction with rosemary is applied on haemorrhoids. Indians in Panama use the leaf juice as a purgative, emmenagogue and vermifuge.

Pineapple is cultivated for fruit, used fresh, canned, frozen, or made into juices, syrups, or candied. Pineapple bran, the residue after juicing, is high in vitamin A, and is used in livestock feed. From the juice may be extracted citric acid, or on fermentation, alcohol. In the Philippines, a fine quality cloth is made from leaf fibers.

The fruit, peel, or juice is used in folk remedies for corns, tumours, and warts. Reported to be abortifacient (a substance that induces abortion), cholagogue (increases the flow of bile and its discharge from the body), depurative (eliminates toxins and purifies the system, especially the blood), diaphoretic (the state of perspiring profusely, or something that has the power to cause increased perspiration), digestive, discutient (serves to disperse morbid matter), diuretic (encourages urination), ecbolic (helping childbirth or causing abortion), emmenagogue, estrogenic (endocrine disruptor), hydragogue (aid in the removal of edematous fluids and promote the discharge of fluid from the bowels), intoxicant, laxative, parasiticide, purgative, refrigerant (a compound used in a heat cycle that undergoes a phase change from a gas to a liquid and back), styptic (stops bleeding), and vermifuge.

Pineapple is a folk remedy for bladder ailments, hypochondria (health phobia), scarlet fever (a disease caused by an exotoxin released by Streptococcus pyogenes. It is characterised by sore throat, fever, a 'strawberry tongue', and a fine sandpaper rash over the upper body that may spread to cover almost the entire body), scurvy (insufficient intake of vitamin C), sores, and sprains.

An antiedemic substance has been reported from the rhizome. Edemic is abnormal accumulation of watery fluid in the spaces between connective-tissue cells. Usually a symptom of diseases of the kidneys, heart, veins, or lymphatic system, which affect water balance in the cells, tissues, and blood. Many real or imagined pharmacological effects are attributed to bromelain: burn, debridement (the removal of dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue), anti-inflammatory action, smooth muscle relaxation, stimulation of muscle contractions, cancer prevention and remission, ulcer prevention, appetite inhibition, enhanced fat excretion, sinusitis relief.

Bromelain is given as an anti-inflammatory agent following dental, gynecological, and general surgery, and to treat abscesses, contusions, hematomas, sprains, and ulcerations.

Pineapple juice from unripe fruits acts as a violent purgative, and is also anthelmintic and ecbolic. Ripe fruit juice is diuretic, but in large doses may cause uterine contractions. Sweetened leaf decoction drunk for venereal diseases. Juice of the leaves consumed for hiccoughs, vermifuge, and as purgative. Juice of ripe fruit regarded also as antiscorbutic, cholagogic, diaphoretic, refrigerant, and useful in jaundice. Young vegetative buds are used for respiratory ailments among Choco children.

Phytochemical analysis indicates that the fruit contains calories, water, protein, fat, carbohydrate, fiber, ash, calcium, phosphorus, iron, sodium, potassium, beta carotene equivalent, thiamine, riboflavin, niacin, and ascorbic acid.