Isolation and Identification of Urocanic Acid Found in Extracts of Raw Wool

Abstract

IN A study of the natural causes of nonscourable discoloration of wool, the question of the presence of urocanic acid in suint was raised.Neither the action of alkali as discussed by Serra and de Matco [12] nor of bacterial pigments studied by Seddon [11] and by Fraser and Mulcock [5] will account for the experimentally induced discoloration when wool is held in the presence of suint at 55° C. and at high humidities; the color is due to neither alkali nor bacterial pigments. As it is nonscourable, it is not caused by lanaurin, the deeply colored suint component discussed by Rimington and Stewart EIOI. It was thought possible that urocanic acid, which has been shown byZenisek and Kral E18] to be present in human perspiration, might also be present in suint and might, either directly or through interaction with other suint components, cause or contribute significantly to this experimental wool discoloration and be involved in natural wool discoloration. Urocanic acid alone on wool when held at 55° C. at high humidities causes discoloration, though less than that caused by suint under the same conditions. However, the concentration of urocanic 1 A laboratory

Studies in Wool Yellowing

“…Absorption of bacterial pigments in the fleece [7,12,34] is also an unlikely cause since these normally occur in hands [26] and the natural yellowness of the scoured wool appears to be more uniformly distributed. On the other hand, the possibility of variation of wool yellowness between different sheep being due to the absorption of different amounts of suint pigments into the fiber [4,5] must be seriously considered. This non-scourable pigmentation, known as &dquo;canary stain,&dquo; like the natural yellowness investigated in the present paper, has been removed by exposure to sunlight [3,6 ] .…”