Various studies have shown that phytoceuticals in Mangosteen (in some cases known to be its xanthones) have properties such as: anti-tumor (shrinks tumors), anti-leukemia, antifungal (critical for all cancer patients), antibacterial (to protect DNA), antioxidants (at least two dozen different kinds of xanthones are in the mangosteen fruit), antiproliferation, kills cancer cells and causes apoptosis (programmed cell death) for some types of cancer.

The mangosteen fruit (Garcinia mangostana L.) is grown in Thailand, Cambodia, Vietnam, India and several other countries. Most of the scientific research on this fruit involves about a half dozen of the two dozen known xanthones in this fruit. Most of the xanthones in Mangosteen have yet to be researched. Mangosteen is said to have a wide range of benefits, most result from its xanthone phytoceuticals/antioxidants. However, mangosteen also contains: catechins, polyphenols, minerals and vitamins.

As an antioxidant, mangosteen is very high among plants:

A new laboratory test known as ORAC (Oxygen Radical Absorbance Capacity) has also shown that an ounce of mangosteen juice has 20 to 30 times the ability to absorb free radicals than one ounce of most fruits and vegetables. The ORAC test is one of the most accurate ways to measure the ability of antioxidants in a certain substance to absorb free radicals. The higher the ORAC score, the better the food is for the body.
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Here are some of the xanthones in mangosteen:

  • alpha-Mangostin
  • beta-Mangostin
  • 3-Isomangostin
  • Mangostanol
  • Gertanin
  • Garcinone A
  • Garcinone B
  • Garcinone C
  • Garcinone D
  • Garcinone E
  • Maclurin

In terms of direct studies on cancer, the following quote is related to cancer:

We found that antiproliferative effect of CME [crude methanolic extract] was associated with apoptosis on breast cancer cell line by determinations of morphological changes and oligonucleosomal DNA fragments. In addition, CME at various concentrations and incubation times were also found to inhibit ROS production. These investigations suggested that the methanolic extract from the pericarp [skin] of Garcinia mangostana had strong antiproliferation, potent antioxidation and induction of apoptosis. Thus, it indicates that this substance can show different activities and has potential for cancer chemoprevention which were dose dependent as well as exposure time dependent.

Antiproliferation, antioxidation and induction of apoptosis by Garcinia mangostana (mangosteen) on SKBR3 human breast cancer cell line,” by Moongkarndi P, Kosem N, Kaslungka S, Luanratana O, Pongpan N, Neungton N.

Heres is another study:

Our results have shown that one of the xanthone derivatives which could be identified as garcinone E has potent cytotoxic effect on all HCC cell lines as well as on other gastric and lung cancer cell lines included in the screen. We suggest that garcinone E may be potentially useful for the treatment of certain types of cancer.

Garcinone E, a Xanthone Derivative, has Potent Cytotoxic Effect Against Hepatocellular Carcinome Cell Lines” by Chi-Kuan Ho, Yu-Ling Huang and Chieh-Chih Chen

There is also research on mangosteen and in vitro leukemia:

We examined the effects of six xanthones from the pericarps of mangosteen, Garcinia mangostana, on the cell growth inhibition of human leukemia cell line HL60. All xanthones displayed growth inhibitory effects. Among them, alpha-mangostin showed complete inhibition at 10 microM through the induction of apoptosis.

Induction of apoptosis by xanthones from mangosteen in human leukemia cell lines,” by Matsumoto K, Akao Y, Kobayashi E, Ohguchi K, Ito T, Tanaka T, Iinuma M, Nozawa Y.

More mangosteen study references can be found at:
http://www.raysahelian.com/mangosteen.html