Source : Webster's Revised Unabridged Dictionary (1913)

Curcumin \Cur"cu*min\ (-m?n), n. (Chem.)
   The coloring principle of turmeric, or curcuma root,
   extracted as an orange yellow crystalline substance,
   {C14H14O4}, with a green fluorescence.

   Note: It possesses acid properties and with alkalies forms
         brownish salts. This change in color from yellow to
         brown is the characteristic reaction of tumeric paper.
         See {Turmeric paper}, under {Turmeric}.