ABSTRACT
The purpose of this research is to investigate why mango could represent such an important food for our health. Mango is a rich source of various polyphenolic compound, like mangiferin, quercetin, catechins, anthocyanins, gallic and ellagic acids and more, that have antioxidant capacity. This capacity is the basis of the defeat of many degenerative disease.
Nutraceutical and pharmaceutical significance of both mangiferin and quercetin have been demonstrated and should be the main object of new researches, since they both have a high potential to prevent and/or combat heart diseases and above all cancer.
INTRODUCTION
Mango is a fleshy stone fruit that belongs to genus Mangifera and it is native to South Asia but has been distributed worldwide becoming one of the most cultivated fruits. The reason why mango should be in everyone’s diet has to be found in its content of a variety of phytochemicals and essential nutrients that play a significant role in our health. In fact it contains a large variety of antioxidant, pigments and vitamins and it can also be considered as a major source of polyphenols (among them mangiferin, catechins, quercetin, anthocyanins, gallic and ellagic acids), that are present in any part of the fruits (pulp, peel, leaf, bark), even if what varies is the amount.
Mangiferin and quercetin in particular, have been widely considered since it is demostrated their potential to combat degenerative diseases like breast and colon cancers.
The aim of this resarch is to show why a diet based on mango has a great significance in human health, with particular attention to mangiferin and quercetin and their effects.
- Mango wikipedia
- Medicinal properties of Mangifera Indica
Mango properties
The increasing interest in the study of mango phenolics is due to the bioactive compounds that were found in it: these compounds are shown to have benifts on our health, having antioxidative (it is considered to be an antioxidant a substance that significantly delays or inhibits the oxidation of a substrate), anticarcinogenic (any chemical that reduces the occurence of cancer or acts against a cancer that do occur) and angiogenesis inhibitory (substance that inhibits the growth of new blood vessels) activities.
Natural Phenol
Natural phenols are small molecule that contain one or more phenolic group; they are produced by plants and microorganisms and most likely play a key role in the regulation of human health. Both mangiferin and quercetin are natural phenol, even though they differ in the number of carbon atoms present in the carbon skeleton; mangiferin is part of the xhantonoids class and quercetin of the flavonoids.
In animals and humans, the metabolism of natural phenols belongs to the xenobiotic metabolism; after ingestion they are activated and conjugated with charged species by a large group of transferases that catalyze the reactions.
Recently the role of mangiferin and quercetin has become the main object of in-depth analysis since they have been discovered to be key players in new interesting positive effects on our health.
- Comprehensive reviews in food science and food safety
MANGIFERIN
Mangiferin, as clarified above, is a xhanthone (which are some of the most potent antioxidants known), mainly found in higher plants, carachterized by its natural antioxidant activity. It has been first isolated from mango leaves (as C 2-beta-D-glucopyranosil-1,3,6,7-tethraydroxanthone), and later in the mango bark (with the structure 1,6,7-trihydroxy-3-methoxy-2-C-beta-D-glucopyranosyl-xanthone), where the resultant content of mangiferin was reported to be higher.
Mangiferin content of mango pulp was found to be about 4.4 mg/kg, seed kernel
42 mg/kg, whereas in dried mango peel it was 1690 mg/kg .
Table 1- Phenolic compounds in mango peel (mg/kg) on dry matter basis.
| Compound | Amount |
|---|
| Mangiferin | 1690.4 |
| Mangiferin gallate | 321.9 |
| Isomangiferin | 134.5 |
| Isomangiferin gallate | 82.0 |
| Quercetin 3-O-galactoside | 651.2 |
| Quercetin 3-O-glucoside | 557.7 |
| Quercetin 3-O-Xyloside | 207.3 |
| Quercetin 3-O-arabinopyranoside | 101.5 |
| Total phenolics | 4066.0 |
It has been found to exhibit wide range of pharmacological effect like: antioxidant, anticancer, antimicrobial, antiallergenic, immunomodulatory.
The most significant appeared to be:
1. Protection of mitochondrial membrane against Fe2+ citrate induced lipid peroxidation: mangiferin was shown to have a iron-complexing ability (*iron-chelating*), that was suggested to be a possible approach in reducing the oxidative damages caused by iron in pathologies related to abnormal intracellular iron distribution or iron overload. In fact, mangiferin apparently removes iron from the Fe2+ citrate complex to form an unstable complex with it, causing the oxidation of Fe2+ to Fe3+ and the consequent formation of a more stable complex with Fe3+ (which does not cause peroxidation).
2. Inihibition of colon tumorigenesis in rats: mangiferin was thought to act as natural chemopreventive agent in colon cancer, inihibiting monamine oxidase activity and subsequently the proliferation of malignant cells in the colonic mucosa of male rats.
3. Anti cancer effect: the bark extract demonstrated its cytotoxic activity against breast cancer cell lines MCF 7, MDA-MB-435 and MDA-N
4. Inihibition of body weight gain: for this reason many diets include the consumption of mango (see point 7)
5. Reduction of the intracellular Ca2+ concentration: this activity has a major importance since the combination of reactive oxygen species and Ca2+ are required for the activation of induced cell death. Therefore mangiferin’s activity of reducing the intracellular Ca2+ concentration represents a protection for T-cells against the unnecessary activation of the induced apoptotic via and cohoperates with the manteinance of lymphocyte homeostasis.
6. Protection against radiation-induced sickness and mortality: this particular characteristic - that is basically radioprotection - needs to be considered when a cancer-suffering patient eats mango during radiotherapy: mangiferin could protect cells against cell death caused by radiation damage, lessening the cytotoxic impact of radiation on breast cancer cells.
7. Inhibition of the glucose absorption from the intestine (hypoglycaemic activity of mangiferin extract): it has been suggested that mangiferin plays a key role in the reduction of blood glucose levels, by inihibiting the enzymes sucrase, isomaltase and maltase (which are involved in the digesting process of carbohydrates into simple sugars). According to some researches, mangiferin is also able to significantly reduce plasma total cholesterol, triglycerides and LDL (the reduction of these values could avoid the increase of free fatty acid availability and oxidation and therefore hyperglicemia). The results suggested that mangiferin can help in the treatment of diabetes (see references). To further validate the results, a rat intestinal preparation in situ was used: the extracts from barks were shown to reduce glucose absorption in type 2 diabetes mellitus rats, whereas in normal rats mangiferin induced a significant improvement in oral glucose tolerance without causing hypoglycaemia.
8. Antibacterial effects (both towards gram-positive and Gram-negative species), in particular with regards to Bacillus pumilus and Salmonella agona; antifungal effects and antiviral effect (mangiferin was studied in vitro against HSV2 and demonstrated not to inactivate the virus but to inhibit its replication).
9. Antiallergenic activities.
Bioactivity of mangiferin:
The mechanism of bioactivities of mangiferin is mainly centered on its capacity to provide cellular protection. This capacity is due to its antioxidant effect, performed at different levels: it decreases the concentration of O2 regarding to membrane lipid peroxidation; it forms a mangiferin-iron complex regarding the metal ions; it regulates polymer chain initiation by interacting with reacting oxygen species; it mantains cellular oxidation-antioxidant balance.
- Mangiferin wikipedia
- Effects of mangiferin on hyperglicemia
- Combination Treatment with Oxaliplatin and Mangiferin Causes Increased Apoptosis and Downregulation of NFκB in Cancer Cell Lines
- Mango Extracts and the Mango Component Mangiferin Promote Endothelial Cell Migration
QUERCETIN
Quercetin is a member of the flavonoide family (the most abundant polyphenols in our diets), quite present in many fruits and vegetables in comparison to other flavones.
Quercetin is well known because it exerts many beneficial health effects, including a protection against osteoporosis and the improvement of cardivascular health. Most of the properties of quercetin (for example anti-inflammatory, anti-allergic and antitoxic effects) are linked to its strong antioxidant action.
Preliminary researches demonstrated that the characteristics of quercetin made it become a candidate for preventing diabetes and heart disease.
The most impressive results found were:
- Antiviral effects: in two different studies published in 2007 was proved how quercetin and its derivates had important roles in fighting two major virus: HBV and HIV-1. Hyperoside (which is the 3-O- galactoside of quercetin) resulted to be a strong inhibitor of HbsAg and HbeAg secretion in 2.2.15 cells (that is a stable cell line containing the HBV strain genome); quercetin itself revelead to be an inhibitor of the HIV-1 reverse transcriptase).
- Anti-inflammatory properties: a Korean research of 2007 showed how quercetin inhibits the production of inflammatory cytokines by blocking the effects of NF-kB (a cellular mediator also associated with chronic inflammatory conditions). Besides its anti-inflammatory effects may derive from its inhibitory effect on COX (ciclooxygenase - an enzym that is responsible for formation of prostaglandins and consequently of inflammation) and LOX (lipo-oxygenase): these inhibition leads to a decrease in inflammatory mediators.
- Anti-obesity: Quercetin turned out to be an inhibitor of fat accumulation by suppressing the maturation of new fat cells and by triggering apoptosis in exsisting fat cells: in fact it blocks the uptake of glucose from the blood (same mechanism explained in point 7 of mangiferin). Studies in animals support the potential anti-obesity effects of quercetin: experiments were conducted using mice and showed how in mice following a high fat diet quercetin produced a increase in energy expenditure wherease in obese, insulin-resistant mice a high dose quercetin supplementation was associated with a reduction of weight gain.
- Modulation of the transactivation of peroxisome proliferator-activated receptors-PPARs - which control many cellular and metabolic processes
- Downregulation: quercetin displayed downregulation of the expression of mutant breast cancer cells, arrest of human leukemic T cells and inhibition of heat shock proteins; epidemiologic studies suggest that the intake of quercetin and other flavonoid can be related to a reduction of the risk of certain cancers (it prevents or slows down cancers involving brain, liver, breast, colon and other tissues). It has been discovered that only high doses of quercetin inhibit cell proliferation in colon carcinoma cell lines and in mammary adenocarcinoma cell lines, whereas low doses increase malignant cells proliferation. Recently a team of oncologists of Cleveland Clinic tried to combine quercetin with curcumin (that showed to be a potential anti-inflammatory and cancer-blocking nutrient) to treat five patients suffering from familiar adenomatous poyposis (a condition that causes the growth of many colonic polyps that ultimately turn into cancer) and they presented- after a 6 months follow up and quercetin treatment- a reduction in size (60%) and number (51%) of polyps.
- Quercetin wikipedia
- Quercetin
- Anti-cancer gallotannin penta-O-galloyl-beta-D-glucose is a nanomolar inhibitor of select mammalian DNA polymerases
CONCLUSIONS
Many researches investigated how useful mango can be against various type of diseases and disorders and this is the reason why it has been named “the king of fruit”. The extensive survey of literature revealed that mango can be an important source of many chemicals and polyphenolic compounds with high antioxidative activity. Impressive data are those referring to mangiferin - whose potential in medicine should be deepened- and quercetin - this versatile molecule than can affect just so many different processes as obesity, cardiovascular disease, asthma and above all cancer. The numerous benefits mango gives, suggest that a diet including mango could prevent the carcinogenic process and ameliorate the progress of a bunch of other diseases. The knowledges we have so far should encourage new researches and trials using mangiferin and quercetin especially in the prevention and treatment of breast and colon cancer (it is necessary to remind that breast cancer is actually the most common invasive cancer in woman).
Effect of mangiferin on hyperglycemia and atherogenicity in streptozotocin diabetic rats, 2003
