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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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
Data is from peer reviewed journal

Data source

Reference
Reference Type:
publication
Title:
Testing Of Some Azo Dyes and Their Reduction Products for Mutagenicity Using Salmonella typhimurium Ta 1538
Author:
R. Colin Garner and Carol A. Nutman
Year:
1977
Bibliographic source:
Mutation Research, 44 (1977) 9-19

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: as mentioned below
Principles of method if other than guideline:
Gene toxicity in vitro study was performed on the Salmonella typhimurium TA 1538 strain to evaluate the mutagenic effect of the test material Chrysoidin
GLP compliance:
not specified
Type of assay:
bacterial gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Details on test material
- Name of test material (as cited in study report): Chrysoidin
- Molecular formula (if other than submission substance): C12-H12-N4
- Molecular weight (if other than submission substance): 212.255 g/mol
- Substance type: Organic
- Physical state: Solid/Powder form
Purity: purification procedure was performed; details not mentioned
- Impurities (identity and concentrations): No data available

Method

Target gene:
AMES assay
Salmonella typhimurium TA 1538 strain
Species / strain
Species / strain / cell type:
S. typhimurium TA 1538
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Test concentrations with justification for top dose:
50, 100 µg/plate
Vehicle / solvent:
Vehicle:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: No data available
Controls
Untreated negative controls:
not specified
Negative solvent / vehicle controls:
yes
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: Acetylaminofluorene (5 and 10 µg/plate)
Details on test system and experimental conditions:
Details on test system and conditions
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Preincubation period:
- Exposure duration: 48 hrs
- Expression time (cells in growth medium): 48 hrs
- Selection time (if incubation with a selection agent): No data available
- Fixation time (start of exposure up to fixation or harvest of cells): No data available

SELECTION AGENT (mutation assays): No data available
SPINDLE INHIBITOR (cytogenetic assays): No data available
STAIN (for cytogenetic assays): No data available

NUMBER OF REPLICATIONS: 2

NUMBER OF CELLS EVALUATED: No data available

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index; cloning efficiency; relative total growth; other: No data available

OTHER EXAMINATIONS:
- Determination of polyploidy: No data available
- Determination of endoreplication: No data available
- Other:

OTHER: No data available
Evaluation criteria:
Numbers of revertants on test plates greater than 30 are classified as being significantly mutagenic
Statistics:
No data available

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 1538
Metabolic activation:
with
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
valid
Untreated negative controls validity:
not specified
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 1538
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
valid
Untreated negative controls validity:
not specified
Positive controls validity:
valid
Additional information on results:
Genotoxicity: Positive
Concentration His+ revertants/plate
Crude Purified
50 931 867
100 1260 1312

Negative
Concentration His+ revertants/plate
Crude Purified
50 11 -
100 11 -
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'. Remarks: Bacterial strain used

Applicant's summary and conclusion

Conclusions:
The given test material Chrysoidin shows positive gene toxicity in vitro result in the presence of S9 metabolic activation system and negative result in the absence of S9 metabolic activation system.
Executive summary:

Gene toxicity in vitro study was performed on theSalmonella typhimurium TA 1538 strain to evaluate the mutagenic effect of the test material Chrysoidin.

Chrysoidin was used at a concentration of 50 and 100 µg/ plate. The test material was purified and retested for mutagenicity again.

Crude chrysoidin induced 931 his+ revertants at 50 µg and 1260 his+ at 100 µg per plate while the purified material induced 867 and 1312 his+ revertants respectively. It was noticed on plates containing dye and the liver enzyme preparation that the colour remaining after 48 h incubation was less than on plates without the liver enzyme. Since reduction of the azo group leads to loss of dye colouration it was presumed that the liver enzyme catalysed this reaction probably through liver azo-reductase, an NADPH2 requiring enzyme. Chrysoidin shows positive gene toxicity in vitro result in the presence of S9 metabolic activation system and negative result in the absence of S9 metabolic activation system.