The colouring matter is found principally in the root bark and is collected when the plants are 3 to 4 years old. If the trees are allowed to mature then hardly any colouring matter remains. The thin roots are most valuable, and above about ½ inch diameter are discarded. The dye is extracted as the glucoside, known as morindin and upon hydrolysis produces the dye.
Morindone is a mordant dye and and gives a yellowish-red colour with an aluminium mordant, chocolate with a chromium mordant and dull purple to black with an iron mordant.
Morindin is also present in Morinda umbellate but not in Morinda longiflora, a native of West Africa.
Although imported into Great Britain and applied to wool and cotton it did not find commercial success.
Structure of morindone: 1,2,5-Trihydroxy-6-methylanthraquinone.
The plants are grown in many tropical climates and produce an edible fruit called Noni, resembling a small breadfruit. While edible, the fruit is quite bitter and is consumed more often for medicinal reasons than culinary ones.
See also: Family Rubiaceae.