Aal, also known as a’l, ach or aich in Hindi, is a common name for the Morinda citrifolia and Morinda tinctoria a species of small evergreen shrubs extensively cultivated in India for making the dye morindone, also known under the trade name "Suranji". Morindone is used for the dyeing of cotton, silk and wool in shades of red, purple and chocolate.
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.
