Mangosteen, the edible fruit of Garcinia mangostana, of the family Clusiaceae (Guttiferae), an evergreen tree native to SE Asia. The purple fruit is similar to an orange in size, thickness of the rind, and segmentation. A highly prized tropical fruit with a flavor similar to a grape-apple mixture, the mangosteen is cultivated in the West Indies. The rind is used in traditional SE Asian medicines. The mangosteen is classified in the division Magnoliophyta, class Magnoliopsida, order Theales, family Clusiaceae.
The mangosteen (Garcinia mangostana) is a tropical evergreen tree, believed to have originated in the Sunda Islands and the Moluccas. The tree grows from 7 to 25 meters tall. The rind (exocarp) of the edible fruit is deep reddish purple when ripe. Botanically an aril, the fragrant edible flesh is sweet and creamy, citrusy with some peach flavor. Mangosteen is closely related to other edible tropical fruits such as button mangosteen and lemondrop mangosteen.
Maturation of the exocarp and edible aril
The juvenile mangosteen fruit, which does not require fertilization to form (see agamospermy), first appears as pale green or almost white in the shade of the canopy. As the fruit enlarges over the next two to three months, the exocarp color deepens to darker green. During this period, the fruit increases in size until its exocarp is 6–8 centimeters in outside diameter, remaining hard until a final, abrupt ripening stage.
The subsurface chemistry of the mangosteen exocarp comprises an array of polyphenolic acids including xanthones and tannins that assure astringency to discourage infestation by insects, fungi, plant viruses, bacteria and animal predation while the fruit is immature. Color changes and softening of the exocarp are natural processes of ripening that indicates the fruit can be eaten and the seeds are finished developing.
Mangosteen produces a recalcitrant seed, i.e., perishable, short-lived and must be kept moist to remain viable until germination. Technically nucellar in origin and not the result of fertilization, mangosteen seeds germinate as soon as they are removed from the fruit and die quickly if allowed to dry.
Once the developing mangosteen fruit has stopped expanding, chlorophyll synthesis slows as the next color phase begins. Initially streaked with red, the exocarp pigmentation transitions from green to red to dark purple, indicating a final ripening stage. This entire process takes place over a period of ten days as the edible quality of the fruit peaks.
The edible endocarp of the mangosteen is botanically defined as an aril with the same shape and size as a tangerine 4–6 centimeters in diameter, but is white. The circle of wedge-shaped arils contains 4–8 segments, the larger ones harboring apomictic seeds that are unpalatable unless roasted. On the bottom of the exocarp, raised ridges (remnants of the stigma), arranged like spokes of a wheel, correspond to the number of aril sections. Mangosteens reach fruit-bearing in as little as 5–6 years, but more typically require 8–10 years.
Nutrient content and antioxidant strength
Mangosteen is typically advertised and marketed as part of an emerging category of novel functional foods sometimes called "superfruits" presumed to have a combination of
1) Appealing subjective characteristics, such as taste, fragrance and visual qualities,
2) Nutrient richness,
3) Antioxidant strength and
4) Potential impact for lowering risk against human diseases.
When analyzed specifically for its edible aril, mangosteen meets only the first criterion above, as its overall nutrient profile is absent of important content, it contains no pigmentation (correspondingly, no antioxidant phytochemicals in significant concentration) and there is no scientific evidence of aril constituents having any health properties.
Should purée or juice from the arils be infused with exocarp phenolic extracts, mangosteen juice adopts the purple color and astringency of its exocarp pigments. It is usually balanced for taste with sweeteners possibly requiring juices from other fruits.
Legend, geographic origins and culinary applications
There is a story, possibly apocryphal, about Queen Victoria offering a cash reward to anyone who could deliver to her the fabled fruit. Mangosteens are readily available canned and frozen in Western countries.
Without fumigation or irradiation as whole fruit, mangosteens have been illegal for importation in commercial volumes into the United States due to fears that they harbor the Asian fruit fly which would endanger U.S. crops. This situation, however, officially changed on July 23, 2007 when irradiated imports from Thailand were allowed upon USDA approval of irradiation, packing and shipping techniques.
For the period since 2006 to present, private small volume orders from fruits grown on Puerto Rico are being filled for American gourmet restaurants who serve the aril pieces as a delicacy dessert. Beginning in 2007 for the first time, fresh mangosteens are also being sold for as high as US$45 per pound from specialty produce stores in New York City.
Products derived from the mangosteen are legally imported into the United States, such as juices, freeze-dried fruit and nutritional supplements. The fresh fruit is also available in Australia, Singapore, Thailand, Malaysia, Vietnam, Indonesia, Myanmar, Colombia, the Philippines, Sri Lanka and Chinatowns in several Canadian cities, as well as in the produce section of some grocery stores.
Mangosteen is cultivated and sold on some Hawaiian islands, although presently not exported to the continental United States where it is banned as an insect host. However, Hawaiian growers are working with a Honolulu irradiation facility for future export to the United States mainland. Mangosteen is grown in Central Africa, particularly the Democratic Republic of the Congo where it is a popular delicacy. An ultra-tropical tree, the mangosteen must be grown in consistently warm conditions, as exposure to temperatures below 40°F (4°C) will generally kill a mature plant.
Before ripening, the mangosteen shell is fibrous and firm, but becomes soft and easy to pry open when the fruit ripens. To open a mangosteen, the shell is usually broken apart by scoring it with a knife; one holds the fruit in both hands, prying gently with the thumbs until the rind cracks. It is then easy to pull the halves apart along the crack and remove the fruit, taking care with the purple, inky exocarp juice containing pigments that are an avid dye on skin and fabric.
Xanthone is an organic compound with the molecular formula C13H8O2. It can be prepared by the heating of phenyl salicylate. In 1939, xanthone was introduced as an insecticide and it currently finds uses as ovicide for codling moth eggs and as a larvicide. Xanthol is also used in the preparation of xanthydrol which used in the determination of urea levels in the blood.
Xanthone derivatives
The chemical structure of xanthone forms the central core of a variety of naturally occurring organic compounds, such as mangostin, which are sometimes collectively referred to as xanthones. Over 200 xanthones have been identified. Xanthones are natural constituents of plants in the families Bonnetiaceae and Clusiaceae and are found in some species in the family Podostemaceae. Many of these xanthones are found in the pericarp of the mangosteen fruit (Garcinia mangostana), which can be found in the region of Southeast Asia.
Synthetic derivatives of xanthone can be added during the polymerization of polyester, to form a plastic that has a greater resistance to degradation by ultraviolet light. The most useful derivative is tetrahydroxyxanthone. Polyester film can be used for the production of third generation printed solar cells, to make them a cost effective alternative to silica-based solar energy generation. It was originally intended that the additive be used for polyester greenhouses in hot climates, where the plastic would degrade after a few years from UV exposure. The xanthone-treated product has an extended useful lifetime of ten years instead of three.
Proanthocyanidins
Proanthocyanidin (also known as oligomeric proanthocyanidin (OPC ), pycnogenol, leukocyanidin and leucoanthocyanin) is a class of flavonoids. It was discovered in 1936 by Professor Jacques Masquelier and called Vitamin P, although this name did not gain official category status and has since fallen out of usage. It was Masquelier who first developed techniques for the extraction of Proanthocyanidins from certain plant species.
Proanthocyanidins have been sold as nutritional and therapeutic supplements in Europe since the 1980s, but their introduction to the United States market has been relatively recent.
About
Proanthocyanidins can be found in many plants, most notably pine bark, grape seed, grape skin, and red wines of Vitis vinifera. However, bilberry, cranberry, black currant, green tea, black tea, and other plants also contain these flavonoids. The berries of chokeberry, specifically black chokeberry, have the highest measured concentrations of proanthocyanidin found in any plant to date.
This information attracted the attention of public news media, describing that red wine consumption was associated with favorable intake of health-promoting flavonoids which correlate with oxygen radical absorbance capacity (ORAC).
In red wines, total oligomeric proanthocyanidin content, including catechins, was substantially higher (177.18 +/- 96.06 mg/L) than that in white wine (8.75 +/- 4.53 mg/L). A relative high correlation in red wines was found between ORAC values and malvidin compounds (r = 0.75, P < 0.10), and proanthocyanidins (r = 0.87, P < 0.05).
In white wines, a significant correlation was found between the trimeric proanthocyanidin fraction and peroxyl radical scavenging values (r = 0.86, P < 0.10).
A moderate drink (1 drink per day, about 140 mL) of red wine, or white wine, or wine made from highbush blueberry corresponded to an intake of 2.04 +/- 0.81 mmol of TE, 0.47 +/- 0.15 mmol of TE, and 2.42 +/- 0.88 mmol of TE of ORAC/day, respectively.
Proanthocyanidins are the principal vasoactive polyphenols in red wine which is linked to a reduced risk of coronary heart disease and to lower overall mortality. Proanthocyanidins are present at higher concentrations in wines from areas of southwestern France and Sardinia which are associated with increased longevity in the population. Earlier studies that attributed this health benefit to resveratrol were premature because of the negligible amount of resveratrol in red wine.
Proanthocyanidins suppress production of a protein endothelin-1 that constricts blood vessels.
These studies provide data supporting the French Paradox which hypothesizes that intake of proanthocyanidins and other flavonoids from regular consumption of red wines prevents occurrence of a higher disease rate (cardiovascular diseases, diabetes) in French citizens on high-fat diets.
Proanthocyanidins have antioxidant activity and they play a role in the stabilization of collagen and maintenance of elastin — two critical proteins in connective tissue that support organs, joints, blood vessels, and muscle. Possibly because of their effects on blood vessels, proanthocyanidins have been reported in double-blind research to reduce the duration of edema after face-lift surgery from 15.855468 to 11.486745222 days. In preliminary research, proanthocyanidins were reported to have anti-mutagenic activity (i.e., to prevent chromosomal mutations).
The most common antioxidants currently used are vitamin C and vitamin E; however, studies show that proanthocyanidins antioxidant capabilities are 20 times more powerful than vitamin C and 50 times more potent than vitamin E (Shi). An important supplement, the proanthocyanidins found in pine bark and grape seed extract work directly to help strengthen all the blood vessels and improve the delivery of oxygen to the cells. Doctor recommended as anti-oxidants, they have become increasingly more important as our environment deteriorates through the introduction of toxins from pollution. Proanthocyanidins also have an affinity for cell membranes, providing nutritional support to reduce capillary permeability and fragility. Although flavonoids are widespread in nature, the powerful proanthocyanidin compound is most abundant and available from the bark of the maritime pine and in grape seeds, or pips.
- Proanthocyanidins reduce histamine production naturally, and are used in the treatment of allergies.
- Proanthocyanidins help improve circulation by strengthening capillary walls. This is especially important for people with compromised circulatory systems, such as stroke victims, diabetics, arthritics, smokers, oral contraceptive users and people with general cardiovascular insufficiencies.
- Proanthocyanidins inhibit the body’s enzymes that break down collagen. Proanthocyanidins help collagen repair and rebuild correctly which can reverse damage done over the years by injury and free radical attack. The breakdown of collagen is what causes our skin to lose its elasticity which in turn causes wrinkles. Proanthocyanidins help keep skin elastic, smooth and wrinkle-free. Proanthocyanidins are also taken as an oral cosmetic to help in the prevention of wrinkles.
- Proanthocyanidins serve to protect against environmental toxins, such as radiation, pesticides, pollution, heavy metals, etc. The production of free radicals is increased because of today's environment. Tobacco smoke, alcohol, solvents, chemicals and more cause free radicals to form. Since proanthocyanidins eliminate free radicals, they help us fight the toxic effects of our environment.
- Proanthocyanidins act as a natural, internal sunscreen. The Sun's ultraviolet rays destroy up to 50 percent of our skin cells. Proanthocyanidins reduce this amount to approximately 15 percent. Inhibiting the daily effects the Sun's rays have on our skin is our best defense against the aging of our skin.
- Proanthocyanidins cross the blood-brain barrier to protect the blood vessels in the brain.
Unlike most other nutritional supplements, the beneficial effects of proanthocyanidins cross the blood-brain barrier. This enables proanthocyanidins to fight free radicals in the vessels of the brain that in turn will help them remain healthy. This can result in increased mental acuity, a decreased potential for stroke, and possibly in fighting senility.
Catechins
Catechins are polyphenolic antioxidant plant metabolites. They belong to the family of flavan-3-ols (which are not strickly speaking flavonoids since they have no carbonyl group). Although present in numerous plant species, the largest source in the human diet is from various teas derived from the tea-plant Camellia sinensis.
Catechins are polyphenolic antioxidant plant metabolites. They belong to the family of flavan-3-ols (which are not strickly speaking flavonoids since they have no carbonyl group). Although present in numerous plant species, the largest source in the human diet is from various teas derived from the tea-plant Camellia sinensis.
Sources of catechins
Catechins constitute about 25% of the dry weight of fresh tea leaf, although total catechin content varies widely depending on clonal variation, growing location, seasonal/ light variation, and altitude. They are present in nearly all teas made from Camellia sinensis, including white tea, green tea, black tea and Oolong tea.
Catechins are also present in the human diet in chocolate, fruits, vegetables and wine and are found in many other plant species.
Health benefits of Catechins
The health benefits of catechins have been studied extensively in humans and in animal models. Reduction in atherosclerotic plaques was seen in animal models. Reduction in carcinogenesis was seen in vitro.
Many studies on health benefits have been linked to the catechin content. According to Norman Hollenberg, professor of medicine at Harvard Medical School, epicatechin can reduce the risk of four of the major health problems: stroke, heart failure, cancer and diabetes. He studied the Kuna people in Panama, who drink up to 40 cups of cocoa a week, and found that the prevalence of the "big four" is less than 10%. He believes that epicatechin should be considered essential to the diet and thus classed as a vitamin.
According to one researcher epigallocatechin-3-gallate is an antioxidant that helps protect the skin from UV radiation-induced damage and tumor formation.
Green tea catechins have also been shown to possess antibiotic properties due to their role in disrupting a specific stage of the bacterial DNA replication process.
Flavonoids
Flavonoids are most commonly known for their antioxidant activity. However, it is now known that the health benefits they provide against cancer and heart disease are the result of other mechanisms. Flavonoids are also commonly referred to as bioflavonoids in the media – the terms are largely equivalent and interchangeable, for most flavonoids are biological in origin.
Polysaccharides
Polysaccharides are relatively complex carbohydrates. They are polymers made up of many monosaccharides joined together by glycosidic bonds. They are therefore very large, often branched, macromolecules. They tend to be amorphous, insoluble in water, and have no sweet taste.
When all the monosaccharides in a polysaccharide are the same type the polysaccharide is called a homopolysaccharide, but when more than one type of monosaccharide is present they are called heteropolysaccharides.
Examples include storage polysaccharides such as starch and glycogen and structural polysaccharides such as cellulose and chitin.
Polysaccharides have a general formula of Cn(H2O)n-1 where n is usually a large number between 200 and 2500. Considering that the repeating units in the polymer backbone are often six-carbon monosaccharides, the general formula can also be represented as (C6H10O5)n where n={40...3000}.
Storage Polysaccharides
Starches
Starches are glucose polymers in which glucopyranose units are bonded by alpha-linkages. It is made up of a mixture of Amylose and Amylopectin. Amylose consists of a linear chain of several hundred glucose molecules and Amylopectin is a branched molecule made of several thousand glucose units.
Starches are insoluble in water. They can be digested by hydrolysis, catalyzed by enzymes called amylases, which can break the alpha-linkages (glycosidic bonds). Humans and other animals have amylases, so they can digest starches. Potato, rice, wheat, and corn are major sources of starch in the human diet.
Glycogen
Glycogen is a polysaccharide that is found in animals and is composed of a branched chain of glucose residues. It is stored in liver and muscles.
Structural Polysaccharides
Cellulose
The structural component of plants are formed primarily from cellulose. Wood is largely cellulose and lignin, while paper and cotton are nearly pure cellulose. Cellulose is a polymer made with repeated glucose units bonded together by beta-linkages. Humans and many other animals lack an enzyme to break the beta-linkages, so they do not digest cellulose. Certain animals can digest cellulose, because bacteria possessing the enzyme are present in their gut. The classic example is the termite.
Acidic polysaccharides
Acidic polysaccharides are polysaccharides that contain carboxyl groups, phosphate groups and/or sulfuric ester groups.
Bacterial Capsule Polysaccharides
Pathogenic bacteria commonly produce a thick, mucous-like, layer of polysaccharide. This "capsule" cloaks antigenic proteins on the bacterial surface that would otherwise provoke an immune response and thereby lead to the destruction of the bacteria. Capsular polysaccharides are water soluble, commonly acidic, and have molecular weights on the order of 100-1000 kDa. They are linear and consist of regularly repeating subunits of one ~ six monosaccharides. There is enormous structural diversity; nearly two hundred different polysaccharides are produced by E. coli alone. Mixtures of capsular polysaccharides, either conjugated or native are used as vaccines.
Bacteria and many other microbes, including fungi and algae, often secrete polysaccharides as an evolutionary adaptation to help them adhere to surfaces and to prevent them from drying out. Humans have developed some of these polysaccharides into useful products, including xanthan gum, dextran, gellan gum, and pullulan.
Cell-surface polysaccharides play diverse roles in the bacterial "lifestyle". They serve as a barrier between the cell wall and the environment, mediate host-pathogen interactions, and form structural components of biofilms. These polysaccharides are synthesized from nucleotide-activated precursors and, in most cases, all the enzymes necessary for biosynthesis, assembly and transport of the completed polymer are encoded by genes organized in dedicated clusters within the genome of the organism. Lipopolysaccharide is one of the most important cell-surface polysaccharides, as it plays a key structural role in outer membrane integrity, as well as being an important mediator of host-pathogen interactions. The genetics for the biosynthesis of the so-called A-band (homopolymeric) and B-band (heteropolymeric) O antigens have been clearly defined, and a lot of progress has been made toward understanding the biochemical pathways of their biosynthesis. The exopolysaccharide alginate is a linear copolymer of ß-1, 4-linked D-mannuronic acid and L-guluronic acid residues, and is responsible for the mucoid phenotype of late-stage cystic fibrosis disease. The pel and psl loci are two recently discovered gene clusters that also encode exopolysaccharides found to be important for biofilm formation. Rhamnolipid is a biosurfactant whose production is tightly regulated at the transcriptional level, but the precise role that it plays in disease is not well understood at present. Protein glycosylation, particularly of pilin and flagellin, is a recent focus of research by several groups and it has been shown to be important for adhesion and invasion during bacterial infection.
Sterols
Sterols, or steroid alcohols are a subgroup of steroids with a hydroxyl group in the 3-position of the A-ring. They are amphipathic lipids synthetised from acetyl-coenzyme A. The overall molecule is quite flat. The hydroxyl group on the A ring is polar. The rest of the aliphatic chain is non-polar.
Sterols of plants are called phytosterols and sterols of animals are called zoosterols. The most important zoosterols are cholesterol and some steroid hormones; the most important phytosterols are campesterol, sitosterol, and stigmasterol.
Sterols play essential roles in the physiology of eukaryotic organisms. For example cholesterol forms part of the cellular membrane where its presence affects the cell membrane's fluidity and serves as secondary messenger in developmental signaling.
Plant sterols are also known to block cholesterol absorption sites in the human intestine thus helping to reduce cholesterol in humans.
In humans sterols act to provide important signals and metabolic communications eg. Circadian rhythms, blood clotting.
Fiber
Fiber, threadlike strand, usually pliable and capable of being spun into a yarn. Many different fibers are known to be usable; some 40 of these are of commercial importance, and others are of local or specialized use. Fibers may be classified as either natural or synthetic. The natural fibers may be further classed according to origin as animal, vegetable, or inorganic fibers.
Animal fibers are composed chiefly of proteins; they include silk, wool, and hair of the goat (known as mohair), llama and alpaca, vicuña, camel, horse, rabbit, beaver, hog, badger, sable, and other animals. Vegetable fibers are composed chiefly of cellulose and may be classed as short fibers, e.g., cotton and kapok; or long fibers, including flax, hemp, Manila hemp, istle, ramie, sisal hemp, and Spanish moss. The chief natural inorganic fiber is asbestos. Fibers are also derived from other inorganic substances that can be drawn into threads, e.g., metals (especially gold and silver). Artificial fibers can be produced either by the synthesis of polymers (nylon) or by the alteration of natural fibers (rayon).
Fibers are classified according to use as textile, cordage, brush, felt, filling, and plaiting fibers. The largest volume is used for textiles and cordage. The chief textile fibers used for clothing and domestic goods are cotton, wool, rayon, nylon, flax, and silk. Coarse-textured fibers (principally jute) are used for burlap, floor covering, sacks, and bagging materials. Cordage fibers include most of the long vegetable fibers and cotton. Brush fibers include istle, sisal, broomcorn, palmyra, and animal hairs. The chief felt fibers are rabbit and beaver hair. Filling fibers include horsehair, wool flock, kapok, cotton, and Spanish moss. Plaiting fibers are used for braided articles (e.g., hats, mats, and baskets) and include Manila hemp, sisal, rushes, and grasses.
Flax, hemp, and wool have been used extensively from remote times; cotton, however, became the leading commercial fiber c.1800. The demand for fibers was greatly increased by the invention of spinning and weaving machinery during the Industrial Revolution. The artificial fibers (see synthetic textile fibers) have rapidly grown in diversity and extent of use since the development of rayon in 1884.
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