The mangosteen fruit has a purple black skin and inside has white to pink fleshy segments with big seeds similar to a loquat. While the fruit is apparently magnificent (I've never tried one) it is the juice that people are raving about.

Why? Take a look at its list of uses compiled by David Niven Miller from growyouthful.com;

For centuries, mangosteen has been used in traditional medicines. The Chinese have imported dried mangosteens from Singapore for many years. The sliced and dried rind is powdered and used for dysentery. The rind decoction is taken to relieve diarrhoea, cystitis, thrush, urinary disorders and gonorrhoea. A root decoction is taken to regulate menstruation. As an ointment it is used for eczema and other skin disorders.

The rind of partially ripe fruits contains the polyhydroxy-xanthone derivatives mangostin and beta-mangostin. That of fully ripe fruits contains the xanthones, gartanin, 8-desoxygartanin, and normangostin. A derivative of mangostin, mangostin-e, 6-di-O-glucoside, is a central nervous system depressant and causes a rise in blood pressure.

The mangosteen has antibacterial, antiseptic and fungicidal properties, and is also an antioxidant source. It is the rind, not he pulp of the mangosteen fruit that has the greatest value. After processing, the extract is mixed with other fruit juices for taste. The primary value of this extract is that it seems to be a powerful and wide-spectrum anti-oxidant. However, at this stage there is not a lot of credible research available.

Xanthones are what's pushing the hype. They're an antioxidant that seeks out and destroys free radicals (nothing to do with the crisis in Iraq though). While the push is on to tell the world the benefits of xanthones and that mangosteen fruit juice is the greatest source of such there is mounting evidence that perhaps it has limited benefits.

Enzyme Stuff, and independent site about digestive enzymes reported...

Currently, no clinical trials have proven mangosteen fruit to have anticancer effects in humans and no published studies have proven xanthones to be beneficial to human cells. Additionally, no studies have directly investigated the antioxidant effects of xanthones found in the XanGo fruit drink.

Maybe it's all just another "Emperor's New Clothes" test like the one we all took with wheatgrass. We have gotten over that one, haven't we?