Chromogenic derivatives of AHTN (6-acetyl-1,1,2,4,4,7-hexamethyltetralin) react with amino acids and protein in vitro. Spectral characteristics of the colour products

Three chromogenic products of AHTN have been detected after photo-oxidation and shown to react with glycine or albumin, giving rise first to a blue color, followed by pink and, finally, a dark green colour. The absorption spectrum associated with the late green colour showed an increased absorbance in the long wavelength region of the spectrum, similar to the green colour extracted from the liver of AHTN-treated animals. The colour produced by the chromogenic derivatives of AHTN and by o-diacetylbenzene (a model chromogenic compound) were tightly bound to the protein pellet and resistant to acidic pH, unlike the colour from the ninhydrin reaction. The dark green colour produced in the liver by feeding AHTN to rats was also tightly bound to proteins and stable to acidic pH. These results suggest that both the photo-oxidized chromogenic derivatives of AHTN and o-diacetylbenzene, produce coloured derivatives with amino acids and proteins by a mechanism unrelated to ninhydrin. They also suggest that a chromogenic derivative of AHTN, produced in vivo during prolonged treatment with high doses of AHTN, may be responsible for the green colour of the livers and other tissues from treated animals. The data suggest that the AHTN-derived chromogenic material is metabolite-related rather than representative of a toxic process, although further work is necessary to confirm this hypothesis.