By Paul M. Gross, PhD and Ian Crown
Photos from http://mangosteen.com
Opened mangosteen with inedible pericarp (outer purple rind) surrounding the edible white aril
(other mangosteen pictures available at http://mangosteen.com/FruitPicturesPageTwo.htm)
Over recent years, mangosteen has had increasing growth as a fresh dessert delicacy in gourmet restaurants and as a popular base for mixed juices usually called “mangosteen juice” by a variety of manufacturers. It has often been included in the functional food industry among recent discussions about “superfruits”.
Although a superfruit category has not been defined scientifically, it presumably would involve fruits not only with appealing taste but also characteristics of 1) high nutrient density, 2) superior antioxidant quality, and/or 3) potential health benefits.
Is there sufficient scientific evidence to validate mangosteen as a “superfruit”?
Assessing the nutrition and phytochemistry of mangosteen
This essay summarizes nutrient features of mangosteen and gives perspective on current research about its antioxidant phytochemicals, primarily xanthones.
Mangosteen is composed of an edible white interior pulp (botanically, an aril defined as flesh surrounding seeds) encased in a firm inedible pericarp dense in purple pigmentation (figures above, see 2,7,8 for botanical description and other pictures).
Nutrients. The most remarkable nutritional characteristic of mangosteen aril is its relative absence of essential macro- or micronutrients (Table 1). With only few exceptions from publicly available data noted below, all mangosteen's micronutrients fall below 5% of their respective Dietary Reference Intake (DRI, US National Academy of Science). In the table are the highest content nutrients among some 30 analyzed in mangosteen aril, showing good levels of carbohydrate and dietary fiber, and relatively low content of only a few vitamins and minerals. Many essential vitamins and minerals typically found in fresh citrus fruits either were not reported in these assays or could not be detected as their contents were so low (7,8,11).
Table 1. Nutrients with greater than 5% DRI found in mangosteen aril
Content (per 100 g)
DRI (NAS, adults)
Approx % RDI
* range of values from 3 independent sources: 1) Nutritiondata.com, ref. 11; 2) Mangosteen.com, ref. 7; 3) PurdueUniv. , ref. 8
^ from Nutritiondata.com (note the mangosteen nutrient data in 11 are for 1 cup, needing conversion to 100 g for the above table)
With nutrient content so sparse, mangosteen appears not to qualify for “superfruit status” as would other other rare fruits having excellent nutrient and/or phytochemical contents, such as açai, goji (“wolfberry”) and pomegranate (3). These antioxidant fruits are cast as “superfruits” for meeting the criteria above.
Mangosteen antioxidants: introduction
A subjective index of antioxidant quality among plant foods involves color to rank a plant as “antioxidant-rich”. For example, blueberries contain dense amounts of blue antioxidant pigments (anthocyanins) and are often called Nature's number one antioxidant food. Recent research on antioxidant determinations showed that plant foods with rich color had high scores of oxygen radical absorbance capacity (“ORAC”) whereas those that were white (without pigments) had low ORAC (13). By this simple index, the white edible aril of mangosteen should have a low ORAC. However, no ORAC results have been reported for mangosteen fruit to date.
As predicted from the above data, juice from mangosteen aril could not by itself provide significant nutrition, but the possibility remains that xanthone extracts taken from the pericarp and added to a juice could be beneficial. It is worth noting that all “mangosteen” juices on the market contain juices of other high-antioxidant fruits, such as blueberry, cranberry, raspberry, strawberry and grape (example, 9) – all potentially contributing diverse antioxidant phytochemicals as phenolic pigments that could account for the antioxidant benefit of a juice derived from mangosteen.
Much of the suspected health value of mangosteen juice relies on xanthones (10). However, the potential benefit of xanthones as antioxidant phytochemicals useful to human health, although promising, remains unproven and certainly too early to imply anti-disease effects (7,10).
Mangosteen antioxidants: scientific literature
Below is a review of preliminary findings on mangosteen xanthones from PubMed, the online database of medical abstracts from the US National Library of Medicine (12).
From the search statement “Garcinia” (mangosteen's genus), PubMed retrieved 281 total citations from the period 1959-2006 (search performed January 8, 2007), but only 46 of these were on the mangosteen species (mangostana) within the Garcinia genus. Other citation retrievals and dates can be summarized to show the history of medical research on mangosteen and its xanthone derivatives (PubMed search statements in italics)
- mangostana, first reported in 1979, 46 total
- garcinol, a xanthone not only from mangosteen but also from several Garcinia species, first reported in 1987, 21 total
- mangostin, also a xanthone but specifically from mangosteen, first reported in 1979, 41 total
- mangosteen, first reported in 1992, 28 total
By contrast, “phenolics” (same as polyphenols), an antioxidant class from colorful plants, has been cited over 10,000 times since the 1930s, showing an older and broader research interest developing currently toward confirmation of human health benefits.
The above summary demonstrates that medical research on mangosteen and its xanthones is a relatively young scientific field with only preliminary laboratory evidence for anti-disease properties established to date.
Mangosteen antioxidants: potential health benefits
In recent years, mangosteen has attracted special attention for its xanthone extracts - garcinol and mangostin - having potential as anti-inflammatory agents with preliminary evidence for inhibiting cyclo-oxygenase (COX) enzymes and carcinogens (5,6). From other preliminary research, garcinol may also be an appetite suppressant possibly useful in weight control.
Revealed by PubMed searches, newly discovered xanthones include mangosharin, mangostingone, 8-hydroxycudraxanthone, mangoxanthone and benzphenones whose properties are only at the beginning of scientific description for biological effects.
Other phytochemicals isolated from the inedible pericarp of mangosteen include the benzophenones, aristophenones, depsidones, and garcimangosone D; polysaccharides; flavonoids (methylnaringenin); and terpenoids.
Although research on these phytochemicals is now being published, all evidence to date is preliminary before the more advanced studies needed to confirm biological properties. Such definitive studies are years away, as human research has not yet begun on a scale sufficient to determine potential health benefits of mangosteen pericarp xanthones.
Among preliminary research are the following health topics mostly being studied with in vitro methods on xanthone extracts from the mangosteen pericarp. None has been advanced yet even to laboratory animal studies: anticancer, apoptotic (induction of tumor cell death), antiproliferative (inhibits cell division and migration), antibiotic, anti-inflammatory, antiatherogenic, antimicrobial, antiulcer, antimalarial, immune stimulation, antiviral, antifungal, antivenom, antihistamine, antiserotonin, appetite suppression, antiadipogenic, antiparasitic.
Although the above demonstrates active basic research interest, no acceptable conclusions could be made yet about the health benefits of mangosteen xanthones for humans. Previous critiques on the potential health value of mangosteen juice have cautioned the public to not assume health benefits without evidence from rigorous research including human clinical trials (7,10).
With an understanding of the present state of xanthone research as summarized here, it seems reasonable to conclude that human studies on xanthones are at least a decade away, as there are no approved programs for mangosteen in human research within the NIH database for clinical trials (4).
Mangosteen antioxidants: a perspective on measuring antioxidant strength
One representative measure of antioxidant strength – ORAC, oxygen radical absorbance capacity (13) – has been reported for two brands of mangosteen juice. MangoXan claims 8,650 micromol ORAC units per 100 grams and 5,600 ORAC units for Xango (independent assays by a contract laboratory as cited in 9). Both these juices, however, contain other antioxidant-rich berry juices, such as blueberry and cranberry for which similar ORAC values exist in whole fruit (13). Consequently, ORAC analyses of manufactured “mangosteen” juices that are actually blends of multiple fruit juices do not inform us about the antioxidant strength of mangosteen xanthones.
There have been no published research reports on ORAC specifically of mangosteen aril or pericarp.
Mangosteen as a functional “superfruit”
On December 5, 2006, the FDA began public discussions about whether the emerging category of functional foods should be regulated (1). This process is relevant to products like mangosteen juice whose promotional literature leads consumers to believe that mangosteen's “nutrients” support multiple systems of the body and so may have health effects or prevent diseases (discussion in 10).
The FDA review panel will consider a process for overseeing functional foods being brought to market and may require
- identification of the potential new bioactive ingredient such as xanthones and flavonoids;
- evaluation of an ingredient's efficacy and safety (not established for mangosteen constituents by sufficient research);
- selection of the appropriate food vehicle for a bioactive substance taking into consideration characteristics of the food, the ingredient and the intended consumer;
- independent peer review and, if required, regulatory oversight to ensure accuracy of health claims (not undertaken for any brand of mangosteen juice); and
- post-market surveillance to confirm the pre-market assessments (not undertaken by any company marketing mangosteen juice).
Conclusion. Analysis to date indicates that mangosteen is a low-nutrient fruit whose marketed juices are supplemented in taste and antioxidant strength by pericarp xanthones and other fruit juices.
As mangosteen's supposed health claims are not supportable by sufficient nutrient density or a complete research process allowing conclusions about human health benefits, it has not met standards to be a superfruit. Research on xanthones is only at a preliminary stage from which no conclusions regarding lowered disease risk are valid at this time.
1. FDA hears views on what to do about functional foods, Nutraingredients.com USA, December 6, 2006, http://www.nutraingredients-usa.com/news/ng.asp?id=72592
3. Gross, P.M. Açaí: potent antioxidant superfruit, NPICenter, January 8, 2007, http://www.npicenter.com/anm/templates/newsATemp.aspx?articleid=17363&zoneid=43
4. Human clinical trial projects, http://clinicaltrials.gov
5. Jung HA, Su BN, Keller WJ, Mehta RG, Kinghorn AD. Antioxidant xanthones from the pericarp of Garcinia mangostana (Mangosteen). J Agric Food Chem. 2006 Mar 22;54(6):2077-82.
6. Liao CH, Sang S, Liang YC,Ho CT, Lin JK. Suppression of inducible nitric oxide synthase and cyclooxygenase-2 in downregulating nuclear factor-kappa B pathway by Garcinol. Mol Carcinog. 2004 Nov;41(3):140-9.
7. Mangosteen, http://mangosteen.com
8. Mangosteen, PurdueUniversityCenter for New Crops and Plant Products, http://www.hort.purdue.edu/newcrop/morton/mangosteen.html
9. MangoXan, Pure Fruit Technologies promotional literature, ORAC analyses by Covance Labs, October 2005.
10. Moss R. A friendly skeptic looks at mangosteen, http://chetday.com/mangosteen.htm
12. PubMed, http://pubmed.gov
13. Wu X, Beecher GR, Holden JM, Haytowitz DB, Gebhardt SE, Prior RL. Lipophilic and hydrophilic antioxidant capacities of common foods in the United States. J Agric Food Chem. 2004 Jun 16;52(12):4026-37.
About the Authors
Paul M. Gross, PhD, received his doctorate in physiology from the University of Glasgow, Scotland and neuroscience training at the Laboratory of Cerebral Metabolism, National Institutes of Health, Bethesda, MD. A former Research Scholar for the Heart and Stroke Foundation of Ontario, he published 85 peer-reviewed journal reports and book chapters over a 25 year career in medical science, and was recipient of the Karger Memorial Award, Switzerland, for publications on brain capillaries. Dr. Gross is on the steering committee of the International Berry Health Association. He is senior author of a 2006 book on the goji berry (Booksurge Publishing, Amazon.com, http://wolfberry.org) and is publisher of The Berry Doctor's Journal, http://berrydoctor.com providing free information on berry science and nutrition.
Ian Crown has a BSc degree in agriculture and operates a mangosteen plantation on Puerto Rico. He is author and publisher of http://mangosteen.com