This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Platzek, T Articles by Baltes, W Search for Related Content PubMed PubMed Citation Articles by Platzek, T Articles by Baltes, W Pubmed/NCBI databases Compound via MeSH Substance via MeSH Hazardous Substances DB 3,3'-DIMETHYLBENZIDINE TRYPAN BLUE Social Bookmarking                         What's this?

Formation of a carcinogenic aromatic amine from an azo dye by human skin bacteria in vitro

Federal Institute for Health Protection of Consumers and Veterinary Medicine, Postfach 330013, D-14191 Berlin, Germany

C Lang

G Grohmann

Institute for Microbiology and Genetics, Technical University Berlin, Gustav-Meyer-Allee 25, D-13355 Berlin, Germany

U-S Gi

W Baltes

Institute for Food Chemistry, Technical University Berlin, Gustav-Meyer-Allee 25, D-13355 Berlin, Germany

Azo dyes represent the major class of dyestuffs. They are metabolised to the corresponding amines by liver enzymes and the intestinal microflora following incorporation by both experimental animals and humans. For safety evaluation of the dermal exposure of consumers to azo dyes from wearing coloured textiles, a possible cleavage of azo dyes by the skin microflora should be considered since, in contrast to many dyes, aromatic amines are easily absorbed by the skin. A method for measuring the ability of human skin flora to reduce azo dyes was established. In a standard experiment, 3610¹¹ cells of a culture of Staphylococcus aureus wereincubatedinsyntheticsweat (pH 6.8, final volume 20 mL) at 288C for 24 h with Direct Blue 14 (C.I. 23850, DB 14). The reaction products were extracted and analysed using HPLC. The reduction product o-tolidine (3,3'-dimethylbenzidine, OT) could indeed be detected showing that the strain used was able to metabolise DB 14 to the corresponding aromatic amine. In addition to OT, two further metabolites of DB 14 were detected. Using mass spectrometry they were identified as 3,3'-dimethyl-4-amino-4'-hydroxybiphenyl and 3,3'-di methyl-4-aminobiphenyl. The ability to cleave azo dyes seems to be widely distributed among human skin bacteria, as, under these in vitro conditions, bacteria isolated from healthy human skin and human skin bacteria from strain collections also exhibited azo reductase activity. Further studies are in progress in order to include additional azo dyes and coloured textiles. At the moment, the meaning of the results with regard to consumer health cannot be finally assessed.

Key Words: azo dyes • skin bacteria • metabolism

Human & Experimental Toxicology, Vol. 18, No. 9, 552-559 (1999)
DOI: 10.1191/096032799678845061


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				H. Chen, H. Xu, O. Kweon, S. Chen, and C. E. Cerniglia Functional role of Trp-105 of Enterococcus faecalis azoreductase (AzoA) as resolved by structural and mutational analysis Microbiology, September 1, 2008; 154(9): 2659 - 2667. [Abstract] [Full Text] [PDF]

				H. Chen, S. L. Hopper, and C. E. Cerniglia Biochemical and molecular characterization of an azoreductase from Staphylococcus aureus, a tetrameric NADPH-dependent flavoprotein Microbiology, May 1, 2005; 151(5): 1433 - 1441. [Abstract] [Full Text] [PDF]

				J. Gan, P. L. Skipper, M. Gago-Dominguez, K. Arakawa, R. K. Ross, M. C. Yu, and S. R. Tannenbaum Alkylaniline-Hemoglobin Adducts and Risk of Non-Smoking-Related Bladder Cancer J Natl Cancer Inst, October 6, 2004; 96(19): 1425 - 1431. [Abstract] [Full Text] [PDF]