Wada, K.G., Koda, T., & Aoki, H. 2005 Analytical and preparative separation of Kaoliang and Lac colors by pH-zone-refining CCC.OU. Journal of Liquid Chromatography & Related Technologies 28(12/13): 2097-2106.

Notes: [3rd International Conference on Countercurrent Chromatography, CCC 2004, Tokyo, Japan, 28-31 August, 2004. Cazes, J. (Ed.)] The natural colouring agents Kaoliang (from Sorghum nervosum [Sorghum bicolor] seed coat) and Lac (from Laccifer lacca [Kerria lacca]) colours were separated using pH-zone-refining countercurrent chromatography (pH-z-CCC) on an analytical or preparative scale. The main components of Kaoliang colour have been reported to be apigeninidin and luteolinidin, however, the structures of other compounds present in the colour have not been elucidated as it is difficult to separate the compounds using conventional chromatographic techniques. Therefore, the separation of this colour was performed by pH-z-CCC that isolated three compounds. LC/MS and SUP 1 H-NMR analyses were used to determine the structures established as a halogenated phenyl compound, p -coumaric acid and methylated apigenin. Lac colour mainly consists of four anthraquinone derivatives, named laccaic acid A, B, C, and E. These four laccaic acids were separated on a large scale by pH-z-CCC. The purified Lac colour (1 g) was submitted to pH-z-CCC with tridodecylamine as a ligand, and produced 790, 41, 109 and 6 mg laccaic acid A, B, C, and D, respectively, with a minimum purity of 96%.