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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From March 23, 1994 to May 31, 1994
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report date:
1994

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
only four bacterial strains were tested. But these were two strains each with base pair substitution and frameshift mutation and thus did not influence the quality and validity of the study
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Reference substance name:
L-Glutamic acid, N-coco acyl derivs., monosodium salts
EC Number:
269-087-2
EC Name:
L-Glutamic acid, N-coco acyl derivs., monosodium salts
Cas Number:
68187-32-6
IUPAC Name:
L-glutamic acid, N-coco-acyl derivs., monosodium salts
Test material form:
solid

Method

Target gene:
Histidine
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
S9-mix induced Aroclor 1254
Test concentrations with justification for top dose:
0, 4, 20, 100, 500, 2500 and 5000 µg/plate (all doses were tested in triplicates)
The test substance proved to be toxic for the bacterial strain TA 100 in the absence of a metabolizing system at a dose of 5000µg/plate only in the cytotoxic experiment. Therefore 5000 µg/plate was chosen as the highest dose in the experiment.
Vehicle / solvent:
Bi-distilled water
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
9-aminoacridine
2-nitrofluorene
sodium azide
other: 2- aminoanthracene
Details on test system and experimental conditions:
Test group:
Top agar was prepared for the Salmonella strains by mixing 100 mL agar (0.6% agar, 0.5% NaCI) with 10 mL of a 0.5 mM histidine-biotin solution.The following ingredients were added (in order) to 2 mL of molten top agar at approx. 45°C:
- 0.1 mL of an overnight nutrient broth culture of the bacterial tester strain
- 0.1 mL test compound solution
- 0.5 mL S-9 Mix (if required) or buffer
After mixing, the liquid was poured into a petridish with minimal agar (1.5% agar, Vogel-Bonner E medium with 2% glucose). After incubation for approximatly 48 h at approx. 37°C in the dark, colonies (his* revertants) were counted.
Two independent experiments were performed.
Evaluation criteria:
A test substance is classified mutagenic if either of the following conditions under a) and b) is achieved:
a) a test substance produces at least a 2-fold increase in the mean number of revertants per plate of at least one of the tester strains over the mean number of revertants per plate of the appropriate vehicle control at complete bacterial background lawn
b) a test substance induces a dose-related increase in the mean number of revertants per plate of at least one of the tester strains over the mean number of revertants per plate of the appropriate vehicle control in at least two to three concentrations of the test article at complete bacterial background lawn.The test results must be reproducible.

Results and discussion

Test results
Key result
Species / strain:
S. typhimurium, other: TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
- Water solubility: the test substance did not precipitate on the plates up to the highest investigated doses
- Precipitation: no

Applicant's summary and conclusion

Conclusions:
Under the study conditions, the substance was not mutagenic in S. typhimurium strains with and without metabolic activation.
Executive summary:

A study was conducted to determine the in vitro genetic toxicity of the substance according to OECD Guideline 471, in compliance with GLP. Salmonella typhimurium strains TA1535, TA1537, TA98 and TA100 were exposed to the test substance at concentration levels of 0, 4, 20, 100, 500, 2500 and 5000 µg/plate with and without metabolic activation (S9-mix induced Aroclor 1254), and to negative or positive control substances for 48 h. In the dose range finding study, the test substance proved to be toxic for the bacterial strain TA 100 in the absence of a metabolizing system at a dose of 5000 µg/plate. Therefore 5000 µg/plate was chosen as the highest dose in the experiment. The test substance did not precipitate on the plates up to the highest investigated doses. The test substance did not induce toxicity or an increase in number of revertants at any concentration level. Under the study conditions, the substance was not mutagenic in S. typhimurium strains with and without metabolic activation (Hoechst, 1994).