curcumin

[Low Lat. curcum ( a ), and Eng. suff. -in ( Chem.) (q. v.).] Chem.: C14H1404. The coloring matter of turmeric (q.v.). Curcumin is very soluble in alcohol and in ether. It is best extracted by boiling the rhizome with benzene. It forms orange-yellow crystals, which melt at 177°. It di olves in alkalies, forming a brown-red solution. Boric acid solution gives an orange color with a solution of curcumin, which is not altered by dilute acids, but alkalies turn it blue, which soon changes into a dirty gray. Hot nitric acid oxidizes curcumin into oxalic acid; chromic acid mixture converts it into terephthalic acid.