Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Toxicological information

Endpoint summary

Currently viewing:

Administrative data

Key value for chemical safety assessment

Additional information

C.I. Basic Yellow 28 methyl sulfate was investigated using the Salmonella/microsome test for point mutagenic effects in doses up to 5000 µg per plate on four Salmonella typhimurium strains. These comprised the histidine-auxotrophic strains TA 1535, TA 100, TA 1537 and TA 98. There was no indication of a bacteriotoxic effect of C.I. Basic Yellow 28 at 8 µg per plate. The total bacteria counts consistently produced results comparable to the negative controls, or differed only insignificantly. Nor was any inhibition of growth noted. Higher doses had a strong, strain-specific bacteriotoxic effect. Therefore they could only be used to a limited extent up to 1000 µg per plate for assessment purposes.

In the first trial, none of the four strains concerned showed a dose related and biologically relevant increase in mutant counts over those of the negative controls. This applied both to the tests with and without S9 mix.

The negative findings for Salmonella typhimurium TA 1535, TA 1537 and TA 98 were confirmed by further repeat tests. In the TA 100 strain, a dose-related minimal increase in mutant counts to 1.6-fold of negative controls was found in the second test. The findings of the second trial for Salmonella typhimurium TA 100 were confirmed by further repeat tests using 30 % and 50 % S9 mix. No relevant increase was found using 10 % S9 mix.

The lowest dose at which this finding was reproducible was approximately 30 µg per plate for Salmonella typhimurium TA 100. Minimally increased mutation rates - below the theshold for positive effects - were obtained only with S9 mix containing 30 % and 50 % S9 fraction in S9 mix.

Basic Yellow 28 methyl sulfate was examined for mutagenic activity by assaying for the induction of 5-trifluorothymidine resistant mutants in mouse lymphoma L5178Y cells after in vitro treatment, in the absence and presence of S9 metabolic activation, using a fluctuation method. The test item was dissolved in dimethylsulfoxide (DMSO) at the concentration of 434 mg/mL, corresponding to 4340 μg/mL in the final treatment medium (0.01 M; upper limit). A first cytotoxicity assay was performed, both in the absence and presence of S9 metabolic activation, the test item was assayed at a maximum dose level of 4340 μg/mL and at a wide range of lower dose levels: 2170, 1090, 543, 271, 136, 67.8, 33.9 and 17.0 μg/mL. In the absence of S9 metabolic activation, using the 3 hour treatment time, no cells survived treatment of 136 μg/mL or higher. At the next lower dose level of 67.8 μg/mL, severe toxicity was observed, reducing relative survival (RS) to 14% of the concurrent negative control value, while slight toxicity was noted over the remaining levels tested. Using the 24 hour treatment time, no cells survived to treatment at all dose levels tested, with the exception of 17.0 μg/mL were RS was reduced to 1%. Following treatment in the presence of S9 metabolic activation, using the short treatment time (3 hours), no cells survived treatment of 271 μg/mL or higher. Toxicity was seen over the remaining dose levels ranging from 1% to 66% RS of the concurrent negative control value. An additional cytotoxicity assay was performed using the 24 hour treatment time. The test item was assayed at a maximum dose level of 17.0 μg/mL and at a wide range of lower dose levels: 8.50, 4.25, 2.13, 1.06, 0.531, 0.266, 0.133 and 0.0664 μg/mL. Severe toxicity was seen at the two highest dose levels, while at the next lower dose level of 4.25 μg/mL, moderate toxicity was observed, reducing relative survival (RS) to 39% of the concurrent negative control value. No toxicity was observed over the remaining dose levels tested. Based on the results obtained in the preliminary trial, two independent assays for mutation at the TK locus were performed using the dose levels described in the following table:

Main Assay I (+/-S9): 68.0, 54.4, 43.5, 34.0, 17.0, 8.50 and 4.25 μg/mL

Main Assay II (-S9): 6.80, 5.23, 4.02, 2.01, 1.01 and 0.503

Main Assay II (+S9): 68.0, 45.3, 30.2, 20.1 and 13.0 μg/mL

Adequate levels of cytotoxicity, covering a range from the maximum to slight or no toxicity, were observed in all treatment series. No relevant increases in mutant frequencies were observed following treatment with the test item, in the absence or presence of S9 metabolism. Negative and positive control treatments were included in each mutation experiment in the absence and presence of S9 metabolism. The mutant frequencies in the solvent control cultures fell within the normal range. Marked increases were obtained with the positive control treatments indicating the correct functioning of the assay system. It is concluded that the test item does not induce mutation at the TK locus of L5178Y mouse lymphoma cells in vitro in the absence or presence of S9 metabolic activation, under the reported experimental conditions.

The micronucleus test was employed to investigate C. I. Basic Yellow 28 methyl sulfate in male and female mice for a possible clastogenic effect on the chromosomes of bone marrow erythroblasts. The known clastogen and cytostatic agent, cyclophosphamide, served as positive control. The treated animals received a single intraperitoneal administration of either Basic Yellow 28 or cyclophosphamide. The femoral marrow of groups treated with Basic Yellow 28 was prepared 16, 24 and 48 hours after administration. All negative and positive control animals were sacrificed after 24 hours. The doses of Basic Yellow 28 and the positive control, cyclophosphamide, were 5 and 20 mg/kg body weight, respectively. The animals treated with Basic Yellow 28 showed symptoms of toxicity after administration. One of forty animals died before the end of the test due to the acute intraperitoneal toxicity of 5 mg/kg Basic Yellow 28.

There was an altered ratio between polychromatic and normochromatic erythrocytes. No indications of a clastogenic effect of Basic Yellow 28 were found after a single intraperitoneal treatment with 5 mg/kg. Cyclophosphamide, the positive control, had a clear clastogenic effect as is shown by the biologically relevant increase in polychromatic erythrocytes with micronuclei. The ratio of polychromatic to normochromatic erythrocytes was not altered.


Short description of key information:
The test item was tested as not genotoxic in a battery of in vivo/in vitro tests, which were performed according to OECD guidelines 471 (Ames test), 474 (in vivo micronucleus test) and 476 (in vitro gene mutation). Based on the available data the test item is considered to be non-genotoxic.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Genotoxicity of the test item was assessed in an in vitro/in vivo testing battery under GLP. The substance was not genotoxic in any of the test systems. Therefore, based on the available data no classification of the target substance is warranted.