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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:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non GLP study conducted equivalent/similar to OECD guideline 471 with the following deviation: only six strains of Salmonella typhimurium were used. The read-across rationale can be found in the category approach document attached in Section 13.

Data source

Reference
Reference Type:
other: Published literature
Title:
Primary Mutagenicity Screening of Food Additives Currently Used in Japan
Author:
Ishidate M, Sofuni T, Yoshikawa K, Hayashi M, Nohni T, Sawada M, et al.
Year:
1984
Bibliographic source:
Fd Chem. Toxic, 22: 623-636

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
neither Salmonella typhimurium TA102 or E.coli WP2 were included
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Reference substance name:
Sodium nitrate
EC Number:
231-554-3
EC Name:
Sodium nitrate
Cas Number:
7631-99-4
IUPAC Name:
sodium nitrate
Details on test material:
- Name of test material (as cited in study report): sodium nitrate
- Analytical purity: 99.3%

Method

Target gene:
histidine locus
Species / strain
Species / strain / cell type:
S. typhimurium, other: TA 92, TA 1535, TA 100, TA 1537, TA 94, and TA98
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
rat liver S9
Test concentrations with justification for top dose:
Six different concentrations were used with the max concentration (the highest non-cytotoxic concentration used in the experiment) being 5.0 mg/plate. No further information was provided.
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: phosphate buffer
- Justification for choice of solvent/vehicle: sample was soluble in water
Details on test system and experimental conditions:
METHOD OF APPLICATION: preincubation


DURATION
- Preincubation period: 20 min
- Exposure duration: 48 hours
- Selection time (if incubation with a selection agent): 48 hours



SELECTION AGENT (mutation assays):
- histidine (S. typhimurium strains)



NUMBER OF REPLICATIONS:
-2






Evaluation criteria:
The result was considered positive if the number of colonies found was twice the number in the control (exposed to the appropriate solvent or untreated).

Results and discussion

Test results
Species / strain:
S. typhimurium, other: TA 92, TA 1535, TA 100, TA 1537, TA 94, and TA98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: not cytotoxic up to the highest dose reported.
Vehicle controls validity:
not specified
Untreated negative controls validity:
not applicable
Positive controls validity:
not specified
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Under conditions of the assay, the test substance was negative for mutagenic activity in the AMES reverse mutation assay at concentrations up to 5.0 mg/plate