Mutagenicity of malachite green and leucomalachite green inin vitro tests

Abstract

The genotoxic potential of the fungicide malachite green (MG) and its reduced derivative leucomalachite green (LMG) was assessed in bacteria and mammalian cells using the standard Salmonella typhimurium/Ames and CHO/HGPRT tests. In vitro potential DNA damaging effects of MG and LMG were tested using the single‐cell gel electrophoresis (Comet) assay on CHO cells. Malachite green was found to be extremely cytotoxic to bacteria and mammalian cells. It did not have any mutagenic activity, in any bacterial strains, in the presence or absence of metabolic activation for doses up to 10 μg per plate. In the CHO/HGPRT test, the mutagenic potential of MG could be evaluated only for very low concentrations ranging from 0.001 to 0.05 μg ml−1 medium. When S9 fraction was added to the medium, the highest tested dose could be increased to 1 μg ml−1. In these experimental conditions, MG did not increase the number of thioguanine‐resistant mutants. Leucomalachite green was less toxic than MG to Salmonella typhimurium and did not have mutagenic activity in the Ames’ test for doses up to 2000 μg per plate. It was also less cytotoxic than MG to CHO cells and was tested at doses ranging from 5 to 100 μg ml−1. Overall results indicated that LMG was not mutagenic in the HGPRT test. In the Comet assay, MG induced DNA damage only at cytotoxic doses. Loss of cell viability was observed for doses of ⩾ 3 μg ml−1, with parallel increase in DNA alterations as measured by the tail moment. After metabolic activation, however, DNA damage was observed at doses (15–20 μg ml−1) inducing only low cytotoxicity. In this case, the direct genotoxicity of MG metabolites could not be excluded. In the absence or presence of metabolic activation, LMG did not have any effect on cell viability or DNA damage for doses up to 500 μg ml−1. This study indicates that LMG, which is the main residue found in fish tissues after treatment with MG, did not have any mutagenic or clastogenic effects in the experimental conditions used. Copyright © 1999 John Wiley & Sons, Ltd.

Mutagenicity of textile dye products

“…Positive results with gene mutation tests with E. coli and yeast have been reported by Combes and Haveland-Smith (1982). Fessard et al (1999) also stated a negative result in an assay for mutations at the hypoxanthine-guanine phosphoribosyltransferase (HGPRT) locus in Chinese hamster ovary (CHO) cells. Evaluation was restricted, however, due to severe cytotoxicity.…”

Bioremoval of toxic dye by using different marine macroalgae

“…MG is highly cytotoxic to mammalian cells (Fessard et al, 1999) and carcinogenic to the liver, thyroid, and other organs of experimental animals (Mahudawala et al, 1999). Incidences of tumors in the lungs, breast, and ovaries have been reported in rats exposed to MG.…”

Negative effects of malachite green and possibilities of its replacement in the treatment of fish eggs and fish: a review

“…No genotoxic effects induced by leucomalachite green were demonstrated in vitro, and malachite green effects in vivo were confirmed only by the positive results of tests on transgenic mice. These findings suggest a low or even doubtful genotoxic potential of the two compounds (Fessard et al, 1999).…”

“…On the other hand, Werth (1958) reported a marked increase in the number of tumours in internal organs of rats that were fed a diet containing malachite green. Werth (1958) also reported defects in up to nine generations of the progeny of rats after oral application of 1 mg malachite green, which is also contradictory to conclusions drawn by Fessard et al (1999). Although it is difficult to pronounce on any dependence between genotoxic and carcinogenic properties on the basis of the information presented, malachite green nevertheless appears to be a promoting agent in the formation of nodular lesions (Culp et al, 2006).…”