Metabolite Screening of Aromatic Amine Hair Dyes Using In Vitro Hepatic Models
October 2009
in “
Xenobiotica
”
aromatic amine hair dyes toluene-2,5-diamine p-aminophenol m-aminophenol p-methylaminophenol N,N′-bis(2-hydroxyethyl)-p-phenylenediamine 1-hydroxyethyl-4,5-diaminopyrazole 4-amino-2-hydroxytoluene 2-methyl-5-hydroxyethylaminophenol phenyl methyl pyrazolone oxidative metabolism human liver microsomes hepatocytes
TLDR The tested hair dye ingredients do not form harmful oxidized metabolites in the liver.
The study investigated the potential oxidative metabolism of nine aromatic amine compounds used in hair dyes using human liver microsomes and hepatocytes. Toluene-2,5-diamine (TDA), p-aminophenol, m-aminophenol, p-methylaminophenol, N,N′-bis(2-hydroxyethyl)-p-phenylenediamine, and 1-hydroxyethyl-4,5-diaminopyrazole showed no evidence of oxidative metabolism. While oxidized metabolites of 4-amino-2-hydroxytoluene (AHT), 2-methyl-5-hydroxyethylaminophenol (MHEAP), and phenyl methyl pyrazolone (PMP) were detected, they did not exhibit NADPH-dependent covalent binding, indicating they were not reactive. Further studies in human hepatocytes revealed that all compounds underwent conjugation without forming oxidative metabolites. The findings suggested that the tested hair dye ingredients did not metabolize into potentially reactive oxidized metabolites in the liver.
