How Mangosteen juice works The Mangosteen (garcinia mangostana) is a tropical fruit growing in South-East Asia. It is sometimes referred to as the ‘Queen of Fruits’. Benefits of Mangosteen Juice Mangosteen juice is a potent source of antioxidants - substances which protect the body from the harmful effects of free radicals and oxidative damage. Xanthones - one of the most powerful antioxidants ever discovered. Xanthones are highly effective free-radical scavengers. The rind, or ‘pericarp’ of the Mangosteen is one of the richest sources of xanthones found in nature.