Mangosteen - The Xanthone Fruit!Xanthones (pronounced zan-thone) are abundantly found in the Mangosteen fruit. Consisting of a smooth dark outer skin and a snow-white fleshy interior pulp, the Mangosteen fruit's xanthone content is of the highest levels researchers have found. Xanthones by definition are biologically active plant phenols that posses a high degree of medicinal properties. Garcinia Mangostana L. or the Mangosteen tree, is a natural source of dietary xanthones that offer a wide range of health benefits.