The Morinda Citrifolia plant is told among the people of the world wide
tropics.  In Malaysia, it is called Mengkudu.  In Southeast Asia it is
known as NHAU.
The plant is recognized among all peoples of the South Pacific.  It is called NONU
in Samoa and Tonga, NONO in Raratonga and Tahiti, and NONI in the Marquesas
Islands and Hawaii.

The fruit of the Morinda Citrifolia was an important source of food by the
early Polynesians, who consumed it in times of famine.  Australian
aborignes were fond of the fruit.  People in Burma cooked unripe fruits in
curries, while the ripened fruits were eaten raw with salt.
The seeds, leaves, bark and root were also ate by people versed with the
properties of this odd  plant.

The amazing thing about the Morinda Citrifolia plant is that every part is
used. 

The Morinda Citrifolia plant flourishes on the islands of French Polynesia, of which
Tahiti is the best known.  The plant reaches heights of 15-20 feet and yields fruit  year
round.  The blossoms of the plant are a creamy white color.  The mature fruit is about
the size of a potato and resembles a small breadfruit.

Tahiti, because of the ideal climate , soil conditions and the pristine environment, is the
superior source of Morinda Citrifolia.  It grows larger and more lush there.

Dr. Ralph Heinicke, as a researcher in Hawaii, grew mindful of the amazing uses of the
Morinda Citrifolia fruit and set out to discover the harmacologically active ingredient of
Morinda Citrifolia.  Dr. Heinicke spent over 45 years studying the effects of an alkaloid
he discovered and named xeronine.  Xeronine, a relatively small alkaloid, is physiologically
active and important for the proper functioning of all cells in the body.
Dr. Heinicke discovered that the Morinda Citrifolia juice contains appreciable amounts  of
the precursor of xeronine that he name proxeronine. Proxeronase also abundant in the juice of the noni fruit, is the enzyme necessary to complete the chemical reaction which produces Xeronine.  Proxeronine combines with Proxeronase in the intestine to produce Xeronine.
 

References:

J. Morton, The Ocean-Going Noni, or Indian Mulberry (Morinda Citrifolia,
Rubiaceae) and Some of Its Colorful Relatives,
Econ. Bot. 46(3)  pp. 241-256, 1992

Medicinal Chest from the Malaysian Rainforest, 1996

Isabella Alona Abbott, La'au Hawai'i, Traditional Hawaiian Uses of Plants.

Otto Degener, B.S., M.S., Illustrative of Plants and Customs of the South Seas

Mala La'au:  A Garden of Hawaiian Healing Plants, 1996

Alexander Dittmar, Morinda Citrifolia L.--Use in Indigenous Samoan Medicine,
Journal of Herbs and Medicinal Plants.
Vol. 1(3), 1993