Terminalia ferdinandiana, also called the Gubinge, billygoat or Kakadu plum or Murungais a flowering plant in the family Combretaceae, native to Australia, widespread throughout the tropical woodlands from northwestern Australia to eastern Arnhem Land. Its fruit has the highest known vitamin C concentration.
The Kakadu plum is most notable for its enormous vitamin C content; it may be the world's richest natural fruit source of this essential vitamin, containing over 5% vitamin C by weight - 50 times the concentration found in oranges and significantly more than the second highest, the South American camu camu. Research by Vic Cherikoff of the University of Sydney's Human Nutrition Unit first confirmed this fruit's exceptional vitamin C content at 3.2% but since, fruits over 5% have been found. Additionally, high levels of folates were measured and more recently, investigators found the equally remarkable content of polyphenolic antioxidants.
Today, the Kakadu plum is more commonly sold as an ingredient for cosmetics but is slowly entering new markets as a nutraceutical in food supplements and fortified beverages. While the fruits have been trialled in plantation and some harvests from these irrigated fields is now supplying market demand, the vitamin C levels tend to fall with the less harsh growing conditions compared to wild stands of trees. Aboriginal communities in Australia's Top End benefit as they wild harvest the fruits to supply the growing demand. Unfortunately, some illegal activities have caused problems with trees being cut down as a means of harvesting the fruits.