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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2007
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Metabolic activation system:
rat liver S9 mix
Test concentrations with justification for top dose:
3; 10; 33; 100; 333; 1000; 2500; and 5000 μg/plate

Results and discussion

Test results
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
no cytotoxicity, but tested up to precipitating concentrations
Remarks:
Only in strain TA 1535 in the presence of metabolic activation a minor reduction in the number of revertants, was observed at 5000 μg/plate.
Positive controls validity:
valid
Remarks on result:
other: strain/cell type: TA 1537 and TA 98 in the absence and presence of metabolic activation and in strain TA 100 in the absence of metabolic activation
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
positive

In conclusion, it can be stated that during the described mutagenicity test and under the experimental conditions reported, the test item did induce gene mutations by frameshifts and base-pair substitutions in the genome of the strains TA 1537, TA 98, and TA 100.
Therefore, C.I. Pigment Orange 5 is considered to be mutagenic in this Salmonella typhimurium and Escherichia coli reverse mutation assay.
Executive summary:

This study was performed to investigate the potential of C.I Pigment Orange 5 to induce gene mutations according to the plate incorporation assay with rat liver S9 (experiment I) using the Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100, and the Escherichia coli strain WP2 uvrA. Since a positive response was observed, a second experiment was not performed.

The assay was performed with and without liver microsomal activation. Each concentration, including the controls, was tested in triplicate. The test item was tested at the following concentrations:

Pre-Experiment/Experiment I : 3; 10; 33; 100; 333; 1000; 2500; and 5000 μg/plate

The plates incubated with the test item showed normal background growth up to 5000 μg/plate with and without metabolic activation.

No toxic effects, evident as a reduction in the number of revertants, were observed with and without metabolic activation in the strains used. Only in strain TA 1535 in the presence of metabolic activation a minor reduction in the number of revertants, was observed at 5000 μg/plate.

A substantial and dose dependent increase in revertant colony numbers was observed following treatment with Hansa-Rot GG in strains TA 1537 and TA 98 in the absence and presence of metabolic activation and in strain TA 100 in the absence of metabolic

activation.

Appropriate reference mutagens were used as positive controls and showed a distinct increase of induced revertant colonies.