title: Structure of acid-stable carmine.
abstract: Acid-stable carmine has recently been distributed in the U.S. market because of its good acid stability, but it is not permitted in Japan. We analyzed and determined the structure of the major pigment in acid-stable carmine, in order to establish an analytical method for it. Carminic acid was transformed into a different type of pigment, named acid-stable carmine, through amination when heated in ammonia solution. The features of the structure were clarified using a model compound, purpurin, in which the orientation of hydroxyl groups on the A ring of the anthraquinone skeleton is the same as that of carminic acid. By spectroscopic means and the synthesis of acid-stable carmine and purpurin derivatives, the structure of the major pigment in acid-stable carmine was established as 4-aminocarminic acid, a novel compound.
authors: National Institute of Health Sciences: 1-18-1, Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
authors: Naoki
authors: N
authors: Sugimoto
authors: Yoko
authors: Y
authors: Kawasaki
authors: Kyoko
authors: K
authors: Sato
authors: Hiromitsu
authors: H
authors: Aoki
authors: Takahito
authors: T
authors: Ichi
authors: Takatoshi
authors: T
authors: Koda
authors: Takeshi
authors: T
authors: Yamazaki
authors: Tamio
authors: T
authors: Maitani
mesh_terms: D000143:Acids; D000880:Anthraquinones; D002329:Carmine / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D005505:Food Coloring Agents / Q000737:chemistry*; D037102:Lectins / Q000737:chemistry; D008745:Methylation; D013057:Spectrum Analysis
chemical_list: D000143:Acids; D000880:Anthraquinones; D005505:Food Coloring Agents; D037102:Lectins; D002329:Carmine; C511975:purpurin anthraquinone