The pigments of crude cottonseed oils. II. Nitrogen-containing pigments derived from Gossypol

Summary Dark, crude cottonseed oil has been shown to contain a mixture of ninhydrin-sensitive substances combined with gossypol. Phenylalanine, aspartic acid, and glycine have been obtained by acid hydrolysis of the addition compound, followed by paper chromatography of the hydrolysate. The presence of other amino acids was indicated, but their identification could not be established with certainty; proline and hydroxyproline were apparently absent. The possibility that part of the color of dark, crude oils arises from gossypol-α-amino acid interaction is discussed. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.