Potencial tóxico de tinturas capilares oxidativas e não oxidativas
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2021-09-03
Autores
Lima, Maria Gabriela Franco de
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Universidade Estadual Paulista (Unesp)
Resumo
O cabelo humano, assim como qualquer outro pelo de mamíferos, tem como função a proteção e regulação da temperatura corporal, pela facilitação dos processos de transpiração e evaporação. Contudo, essa estrutura também é um importante elemento estético do indivíduo, pois dá forma ao rosto e contribui para a construção da identidade pessoal. Sabe-se que desde a antiguidade, os povos utilizavam diversos elementos naturais para tingir os cabelos, porém, foi só no início do século XX que a primeira tintura sintética foi produzida. Atualmente, as tinturas capilares sintéticas são amplamente utilizadas por homens e mulheres em todo o mundo. Diante desse contexto, surgiu a necessidade de conhecer os reais efeitos desses produtos sobre à saúde humana e também os possíveis impactos que possam causar ao meio ambiente, pois, esses compostos estão presentes em efluentes industriais e de estações de tratamento de esgoto urbano, podendo, assim, contaminar, inclusive recursos hídricos destinados ao consumo humano. Uma forma de se estudar os possíveis efeitos tóxicos das tinturas capilares é por meio de ensaios com bioindicadores, pois estes permitem entender os mecanismos de ação biológica de compostos químicos. Dessa forma, este trabalho teve como objetivo estudar o potencial fitotóxico e citogenotóxico da tintura capilar oxidativa (permanente) de coloração castanha média (grupo colorimétrico de número 4), em três diferentes formulações: tinturas em pó e em creme, sendo a em creme testada com e sem associação com peróxido de hidrogênio (H2O2). A avaliação da fitotoxicidade das tinturas foi realizada por meio dos ensaios de germinação com Lactuca sativa e Allium cepa e crescimento radicular e do hipocótilo com L. sativa. A citogenotoxicidade, por sua vez, foi avaliada por meio do ensaio de aberrações cromossômicas e nucleares, realizados com o bioindicador A. cepa. Adicionalmente aos ensaios processados com os bioindicadores vegetais, foi também realizada uma ampla revisão sobre os efeitos tóxicos de azocorantes utilizados na formulação de tinturas capilares não oxidativas (do tipo temporárias e semipermanentes), que permitiu a elaboração de um artigo de revisão sobre o assunto. Os ensaios de fitotoxicidade mostraram que a reação da tintura capilar com H2O2 induziu diferenças nos parâmetros avaliados, mostrando que a tintura pode se tornar mais tóxica, após oxidação. Tanto a tintura associada com H2O2 como a em pó induziram diminuição do índice mitótico. Já a tintura não oxidada (sem H2O2) induziu aberrações cromossômicas e nucleares, indicando que os demais componentes presentes na formulação da tintura, como aminas aromáticas, já possuem potencial citogenotóxico. Os resultados encontrados nos ensaios com modelos vegetais expostos a tinturas oxidativas, bem como o que foi encontrado e reportado na revisão bibliográfica a respeito de tinturas não-oxidativas enfatizam que os componentes das tinturas capilares, seus produtos de oxidação e de metabolização apresentam efeitos nos organismos testados nos mais diversos níveis de toxicidade. Tal fato implica o risco que esses compostos apresentam tanto para seres humanos, que possuem contato direto com os produtos, quanto para o meio ambiente, uma vez que tanto os componentes das tinturas, quanto substâncias derivadas da sua oxidação e metabolização são encontrados em efluentes de indústrias e salões de beleza e podem, por consequência, atingir cursos d’água e contaminar e se bioacumular em outros organismos vivos.
Human hair, like any other hair in mammals, has various functions, such as skin protection and regulation of body temperature, through transpiration and evaporation. However, this structure is also an important aesthetic element, since it frames people’s faces and contributes to the building of personal identity. It is known that since ancient times, people used several natural elements to dye their hair, but it was only at the beginning of the 20th century that the first synthetic dye was invented. Currently, synthetic hair dyes are widely used by both men and women all over the world. This gave rise to the need of knowing the real effects of these products on human health and also, the effects that they might cause on the environment since these compounds are present in industrial effluents and urban wastewater treatment plants, and thus, can contaminate water resources destinated to human consumption. One method of studying the likely effects of hair dyes, is by bioassays with bioindicators, because they allow the understanding of the biological mechanisms of action of chemical compounds. Thus, this work aimed at studying the phytotoxic and cytogenotoxic potential of a permanent natural dark brown hair dye (colorimetric group nº4) in three different formulations: powder and cream, being the cream formulation tested with and without association with hydrogen peroxide (H2O2). The phytotoxic evaluation of the dyes was studied by the germination test, with Lactuca sativa and Allium cepa, and the root and shoot elongation test with Lactuca sativa. The cytogenotoxicity, on the other hand, was evaluated by the chromosomal and nuclear aberration assay, using the bioindicator A. cepa. Additionally, to the bioassays done with the vegetable bioindicators, a wide review was done about the toxic effects of azodyes used in the formulation of temporary and semipermanent hair dyes, which allowed the elaboration of a review paper on the subject.The phytotoxicity assays showed that the reaction between the hair dye and H2O2 induced differences in the analyzed parameters, demonstrating that the dye can become more toxic after oxidation. The dye associated with H2O2, as well as the powder formulation induced a mitodepressive effect. On the other hand, the non-oxidated dye (without H2O2) induced chromosomal and nuclear aberrations, indicating that the other components in the dye formulation, such as aromatic amines, also have cytogenotoxic potential. The results found in the plant bioassays with oxidative dyes, as well as what was reported on the review on non-oxidative dyes emphasize that hair dye components, their oxidation and metabolization products induce several toxic effects in various organisms. This fact shows the risk that these compounds present both to humans, who have them applied directly on their skin, and to the environment since both dye components and substances derived from their oxidation and metabolization are found in industrial and beauty saloons effluents and therefore, can reach watercourses, contaminating and bioaccumulating other living organisms.
Human hair, like any other hair in mammals, has various functions, such as skin protection and regulation of body temperature, through transpiration and evaporation. However, this structure is also an important aesthetic element, since it frames people’s faces and contributes to the building of personal identity. It is known that since ancient times, people used several natural elements to dye their hair, but it was only at the beginning of the 20th century that the first synthetic dye was invented. Currently, synthetic hair dyes are widely used by both men and women all over the world. This gave rise to the need of knowing the real effects of these products on human health and also, the effects that they might cause on the environment since these compounds are present in industrial effluents and urban wastewater treatment plants, and thus, can contaminate water resources destinated to human consumption. One method of studying the likely effects of hair dyes, is by bioassays with bioindicators, because they allow the understanding of the biological mechanisms of action of chemical compounds. Thus, this work aimed at studying the phytotoxic and cytogenotoxic potential of a permanent natural dark brown hair dye (colorimetric group nº4) in three different formulations: powder and cream, being the cream formulation tested with and without association with hydrogen peroxide (H2O2). The phytotoxic evaluation of the dyes was studied by the germination test, with Lactuca sativa and Allium cepa, and the root and shoot elongation test with Lactuca sativa. The cytogenotoxicity, on the other hand, was evaluated by the chromosomal and nuclear aberration assay, using the bioindicator A. cepa. Additionally, to the bioassays done with the vegetable bioindicators, a wide review was done about the toxic effects of azodyes used in the formulation of temporary and semipermanent hair dyes, which allowed the elaboration of a review paper on the subject.The phytotoxicity assays showed that the reaction between the hair dye and H2O2 induced differences in the analyzed parameters, demonstrating that the dye can become more toxic after oxidation. The dye associated with H2O2, as well as the powder formulation induced a mitodepressive effect. On the other hand, the non-oxidated dye (without H2O2) induced chromosomal and nuclear aberrations, indicating that the other components in the dye formulation, such as aromatic amines, also have cytogenotoxic potential. The results found in the plant bioassays with oxidative dyes, as well as what was reported on the review on non-oxidative dyes emphasize that hair dye components, their oxidation and metabolization products induce several toxic effects in various organisms. This fact shows the risk that these compounds present both to humans, who have them applied directly on their skin, and to the environment since both dye components and substances derived from their oxidation and metabolization are found in industrial and beauty saloons effluents and therefore, can reach watercourses, contaminating and bioaccumulating other living organisms.
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Palavras-chave
Allium cepa, Lactuca sativa, Azocorantes, Tinturas capilares parmanentes, Citotoxicidade, Genotoxicidade, Azodyes, Permanent hair dyes, Cytotoxicity, Genotoxicity