xanthinine

from Wiktionary, Creative Commons Attribution/Share-Alike License

• n. A poorly-characterised material, related to urea and uric acid, that forms yellow salts, and exhibits a blue fluorescence

from the GNU version of the Collaborative International Dictionary of English

• n. A complex nitrogenous substance related to urea and uric acid, produced as a white powder; -- so called because it forms yellow salts, and because its solution forms a blue fluorescence like quinine.

from The Century Dictionary and Cyclopedia

• n. A colorless, pulverulent compound, C4H3O2N3, prepared by heating ammonium thionurate.