BIOCHEMICAL INTERACTION OF TRYPAN BLUE AND p-DIMETHYLAMINOAZOBENZENE IN THE LIVER OF RAT (II)

THE INHIBITORY EFFECT OF TRYPAN BLUE ON THE EXPERIMENTAL PRODUCTION OF LIVER CARCINOMA

Abstract

The red-coloured component contained in the commercial brands of trypan blue is removed by treatment with hot ethyl alcohol.
By this manipulation, a dye containing relatively small quantities of the red dye component was prepared from the Merck brand to clarify whether the formation of protein-bound DAB in the livers is decreased or delayed in the rats receiving biweekly trypan blue and DAB, when compared with those on DAB alone.
Throughout a dye-feeding period of 20 weeks the bound DAB showed no significant difference in the amount and period of maximum level between trypan bluestained rats and controls.
The red, purple and blue components contained in a solution of trypan blue (Merck) were separated by adsorpto-chromatography on aluminium oxide, and the inhibiting effects of each component on the DAB-carcinogenesis were determined. Of these dye components, the red and purple dyes did not delay the formation of hepatic neoplasia at all, in doses contained in a 1per cent solution of the Merck preparation. The blue dye most closely resembled in its protective effect the branded dye, but the effect by this component was not a clear-cut inhibition, as has been shown to occur previously with the Merck brand.
It could not be stated that the above-mentioned blue dye contains no red and purple components. The blue component was repeatedly purified by a similar adsorpto-chromatography, in order to remove red and purple bye-products. Although the experiment was discontinued when the rats on DAB alone showed a tumour incidence of 71.4per cent, no anticarcinogenic effect was demonstrated in those on this dye preparation and DAB.
In what kinds and in what amounts these bye-products of the commercial brand should be present in trypan blue solution in order to produce minimum toxicity and simultaneously exhibit powerful anticarcinogenic effects, are matters that still remain unclear.