ReviewCarcinogenicity of azo colorants: influence of solubility and bioavailability
Section snippets
Introduction: the problem of carcinogenic azo colorants
Colorants (dyes and pigments) are important industrial chemicals. Following the technological nomenclature, pigments are colorants that are insoluble in the application medium whereas dyes are applied in soluble form. The question of systemic bioavailability, upon inhalation and skin contact, is of particular importance for azo colorants based on carcinogenic aromatic amines (Myslak and Bolt, 1988, Bolt and Golka, 1993).
In the past, azo colorants based on benzidine, 3,3′-dichlorobenzidine,
Metabolism and bioactivation of azo colorants
Azo colorants are biologically active through their metabolites. Azoreduction of these compounds occurs in vivo (Radomski and Mellinger, 1962, Rinde and Troll, 1975, Robens et al., 1980) by an enzyme-mediated reaction. Azoreductases are found in mammalian tissues, particularly in liver (Fouts et al., 1957, Walker, 1970, Martin and Kennelly, 1981, Kennelly et al., 1982), in gut bacteria (Yoshida and Miyakawa, 1973, Chung et al., 1978, Hartman et al., 1978, Cerniglia et al., 1982, Bos et al., 1986
Azo pigments
As azo pigments are per definitionem considered insoluble, the question is of high relevance whether this group of azo colorants is carcinogenic or not, with considerable consequences for labelling and handling of these compounds (Bowman and Nony, 1981, Pylev et al., 1985). As a majority of azo pigments are based on 3,3′-dichlorobenzidine, much of the available experimental data are focused on this group.
The biological activation of 3,3′-dichlorobenzidine is complex (Iba, 1989/1990), but shows
Regulatory consequences
The problem of carcinogenicity of azo colorants was first officially addressed by the German Commission for Investigation of Health Hazards of Chemical Compounds in the Work Area (“MAK-Commission”) which included a new chapter in the MAK-list, since 1988 (DFG, 1988), with the following summary:
Thus, all azo colorants whose metabolism can liberate a carcinogenic aryl amine are suspected of having carcinogenic potential. Due to the large number of such dyes (several hundred) it seems neither
References (63)
- et al.
Internal exposure of rats to benzidine derived from orally administered benzidine-based dyes after intestinal azo reduction
Toxicology
(1986) - et al.
In vivo binding of 3,3′-dichlorobenzidine to rat and mouse tissue DNA
Cancer Lett.
(1990) - et al.
Azo reduction of trypan blue to a known carcinogen by a cell-free extract of a human intestinal anaerobe
Mutat. Res.
(1978) Carcinogenicity studies on different diarylide yellow pigments in mice and rats
Toxicol. Lett.
(1978)- et al.
Chemical monitoring of urine from workers potentially exposed to benzidine-derived azo dyes
Toxicol. Lett.
(1980) - et al.
Metabolism of bisazobiphenyl dyes derived from benzidine, 3,3′-dimethylbenzidine or 3,3′-dimethoxybenzidine to carcinogenic aromatic amines in the dog and rat
Toxicol. Appl. Pharmacol.
(1980) - et al.
Mutagenicity of benzidine and benzidine-congener dyes and selected monoazo dyes in a modified Salmonella assay
Mutat. Res.
(1984) - et al.
Thirteen-week subchronic toxicity studies of Direct Blue 6, Direct Black 38 and Direct Brown 95 dyes
Toxicol. Appl. Pharmacol.
(1980) The metabolism of azo compounds: a review of the literature
Food Cosmet. Toxicol.
(1970)The investigation on the manufacturing plant of organic pigment
Jikeikai Med. J.
(1970)
Industrial exposure in patients with carcinoma of the bladder
J. Soc. Occup. Med.
Zur früheren Exposition von Malern gegenüber Azofarbstoffen
Arbeitsmed. Sozialmed. Umweltmed.
Possible carcinogenic metabolites of azo dye and pigment: trace-level determination of benzidine, 3,3′-dichlorobenzidine and their acetylated and conjugated products in human and hamster urine
IARC Sci. Publ.
Metabolism of nine benzidine-congener-based azo dyes in rats based on gas chromatographic assays of the urine for potentially carcinogenic metabolites
J. Anal. Toxicol.
Metabolism of azo dyes derived from benzidine, 3,3′-dimethylbenzidine and 3,3′-dimethoxybenzidine to potentially carcinogenic aromatic amines by intestinal bacteria
Carcinogenesis
Reduction of azo dyes by intestinal anaerobes
Appl. Environ. Microbiol.
Fate of water-insoluble and water-soluble dichlorobenzidine-based pigments in Fisher 344 rats
J. Toxicol. Environ. Health
Cancer risk associated with employment in the leather and leather products industry
Arch. Environ. Health
Benzidine and its acetylated metabolites in the urine of workers exposed to Direct Black 38
Arch. Environ. Health
Enzymatic reduction of prontosil and other azo dyes
J. Pharmacol. Exp. Ther.
Occupational bladder cancer in textile dyeing and printing workers: six cases and their significance for screening programs
J. Occup. Med.
Use of permanent hair dyes and bladder-cancer risk
Int. J. Cancer
Formation of blastomogenic diphenylamino derivatives as a result of the metabolism of direct azo dyes
Vopr. Onkol.
Cited by (409)
The utility of bioremediation approach over physicochemical methods to detoxify dyes discharges from textile effluents: A comprehensive review study
2024, Sustainable Chemistry and PharmacyDegradation of methyl orange dye using Fe<inf>3</inf>O<inf>4</inf>/GO photocatalyst with iron derived from coastal Glagah Kulon Progo ore
2024, Nano-Structures and Nano-ObjectsContamination of textile dyes in aquatic environment: Adverse impacts on aquatic ecosystem and human health, and its management using bioremediation
2024, Journal of Environmental ManagementCrystal structure, Hirshfeld surface analysis and energy frameworks of 1-[(E)-2-(2-fluorophenyl)-diazan-1-ylidene]naphthalen-2(1H)-one
2024, Acta Crystallographica Section E: Crystallographic CommunicationsRecyclable/degradable materials via the insertion of labile/cleavable bonds using a comonomer approach
2023, Progress in Polymer Science