Institute of Chemistry-State University "Julio de Mesquita Filho"-UNESP-Avenida Professor Francisco Degni, 55, Quitandinha, 14800-900 Araraquara, SP, Brazil.
Federal University of São Carlos, UFSCar, Department of Chemistry, Rod. Washington Luiz Km 235, Monjolinho, 13565-905 São Carlos, SP, Brazil.
Sci Total Environ. 2018 Feb 1;613-614:1093-1103. doi: 10.1016/j.scitotenv.2017.08.271. Epub 2017 Sep 22.
Azo dyes are known as a group of substances with DNA damage potential that depend on the nature and number of azo groups connected to aromatic rings (benzene and naphthalene), chemical properties, e.g. solubility and reactive functional groups, which significantly affect their toxicological and ecological risks. In this paper, we used in vitro models to evaluate the metabolism of selected textile dyes: Disperse Red 73 (DR 73), Disperse Red 78 (DR 78) and Disperse Red 167 (DR 167). To evaluate the mutagenic potential of the textile dyes, the Salmonella mutagenicity assay (Ames test) with strains TA 98 and TA 100 in the presence and absence of the exogenous metabolic system (S9) was used. DR73 was considered the most mutagenic compound, inducing both replacement base pairs (TA 100) and also changing frameshift (TA 98) mutations that are reduced in the presence of the S9 mixture. Furthermore, we used rat liver microsomes in the same experimental conditions of the S9 mixture to metabolize the dyes and the resultant solutions were analyzed using a liquid chromatography coupled to a quadrupole linear ion trap mass spectrometry (LC-MS/MS) to investigate the metabolites formed by the in vitro biotransformation. Based on this experiment, we detected and identified two biotransformation products for each textile dye substrate analyzed. Furthermore, to evaluate the interaction and reactivity of these compounds with DNA, theoretical calculations were also carried out. The results showed that the chemical reaction occurred preferentially at the azo group and the nitro group, indicating that there was a reduction in these groups by the CYP P450 enzymes presented in the rat microsomal medium. Our results clearly demonstrated that the reduction of these dyes by biological systems is a great environmental concern due to increased genotoxicity for the body of living beings, especially for humans.
偶氮染料是一组具有 DNA 损伤潜力的物质，其取决于与芳环（苯和萘）相连的偶氮基团的性质和数量、化学性质，例如溶解度和反应性功能基团，这些性质显著影响其毒理学和生态风险。在本文中，我们使用体外模型来评估选定纺织染料的代谢：分散红 73（DR 73）、分散红 78（DR 78）和分散红 167（DR 167）。为了评估纺织染料的致突变潜力，使用带有 TA 98 和 TA 100 菌株的沙门氏菌致突变性测定（Ames 试验），同时存在和不存在外源性代谢系统（S9）。DR73 被认为是最具致突变性的化合物，它诱导取代碱基对（TA 100），并改变移码突变（TA 98），这些突变在 S9 混合物存在时减少。此外，我们在与 S9 混合物相同的实验条件下使用大鼠肝微粒体来代谢染料，并用液相色谱-四极杆线性离子阱质谱联用（LC-MS/MS）分析所得溶液，以研究体外生物转化形成的代谢物。基于此实验，我们检测并鉴定了分析的每种纺织染料底物的两种生物转化产物。此外，为了评估这些化合物与 DNA 的相互作用和反应性，还进行了理论计算。结果表明，化学反应优先发生在偶氮基团和硝基基团上，表明 CYP P450 酶存在于大鼠微粒体介质中，导致这些基团还原。我们的结果清楚地表明，由于生物系统还原这些染料会增加对生物体（特别是人类）的遗传毒性，因此这是一个重大的环境问题。
