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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:
1990-05-18
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1990
Report date:
1990
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report date:
1992
Reference Type:
study report
Title:
Unnamed
Year:
1993
Report date:
1993

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
there was no strain tested with main DNA target AT (trpE gene) in the first study. Two other studies were conducted with E.coli only.
Qualifier:
according to guideline
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
yes
Remarks:
there was no strain tested with main DNA target AT (trpE gene) in the first study. Two other studies were conducted with E.coli only.
Principles of method if other than guideline:
there was no strain tested with main DNA target AT (trpE gene) in the first study. Two other studies were conducted with E.coli only.
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
4-(trans-4-propylcyclohexyl)acetophenone
EC Number:
406-700-6
EC Name:
4-(trans-4-propylcyclohexyl)acetophenone
Cas Number:
78531-61-0
Molecular formula:
Hill formula: C17H24O CAS formula: C17H24O
IUPAC Name:
1-[4-(4-propylcyclohexyl)phenyl]ethan-1-one

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
S. typhimurium TA 1538
Species / strain / cell type:
E. coli WP2
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
S9 mix from Aroclor-induced male rats
Test concentrations with justification for top dose:
Concentration range in the main test (with metabolic activation): 50, 250, 500, 1000, 2000, 3000, 4000, 5000, 7500, 10000 µg/plate
Concentration range in the main test (without metabolic activation): 50, 250, 500, 1000, 2000, 3000, 4000, 5000, 7500, 10000 µg/plate
Vehicle / solvent:
Solvent: DMSO
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
2-nitrofluorene
sodium azide
N-ethyl-N-nitro-N-nitrosoguanidine
methylmethanesulfonate
other: 2-Aminoanthracene; Daunomycin;
Details on test system and experimental conditions:
Concentration of the test substance resulting in precipitation: 1250 µg/plate

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
True negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
True negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
True negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
True negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1538
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
True negative controls validity:
not examined
Positive controls validity:
valid
Species / strain:
E. coli WP2
Metabolic activation:
with and without
Genotoxicity:
ambiguous
Remarks:
at precipitating concentrations only; Batch No. 315
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
True negative controls validity:
not examined
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
ambiguous
Remarks:
at precipitating concentrations only; Batch No. 315
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
True negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
Batch No. HE 227/92
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
True negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
Batch No. HE 227/92
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
True negative controls validity:
not examined
Positive controls validity:
valid

Any other information on results incl. tables

Please refer to the attached background material.

The test item dose-dependently increased the number of revertants of both, E. coli WP2 and WP2 uvrA. The effects were reproduced in the repeat experiments performed. Maximal increases of 3- to 5-fold over the respective solvent controls were induced. These

effects however occurred at high test material concentrations which strongly precipitated on the agar plates.

This weak mutagenic effects were re-produced in another independent study conducted with the test item in E. coli strains. However, testing a purified batch of the test item negative results were obtained. Therefore, the weak mutagenicity observed is highly likely related to an impurity and not to the test item itself.

Applicant's summary and conclusion

Conclusions:
Under the conditions of this study, the test item was not mutagenic in S. typhimurium strains but weakly mutagenic in E. coli.
Executive summary:

Mutagenic potential of the test item was investigated using Salmonella typhimurium TA 100, TA 98, TA 1535, TA 1537, and TA 1538 as tester strains. The plate incorporation test with and without addition of rat liver S-9 fraction (Aroclor-induced) was used. The test item was tested in two series of experiments at the following concentrations: 50, 250, 1250, 2500, 5000, and 10000 µg/plate.

In another study, mutagenic potential of the test item was investigated using Escherichia coli WP2 and WP2 uvrA as tester strains. Again, the plate incorporation test with and without addition of rat liver S-9 fraction (Aroclor-induced) was used. The test item was tested in four series of experiments at the following concentrations: 50, 250, 1250, 2500, 5000, and 10000 µg/plate.

A third study was conducted using Salmonella typhimurium TA 98, TA 100, TA 102, TA 1535 and TA 1537 and Escherichia coli WP2 and WP2 uvrA as tester strains. The plate incorporation test with and without addition of liver S9-Mix from Aroclor 1254-pretreated rats was used. The test item was tested in two series of experiments at the following concentrations: 25, 50, 250 1250, 2500, 5000, and 10000 µg/plate.

9-Aminoacridine, daunomycin, 1 -ethyl-2 -nitro-3 -nitrosoguanidine, methyl methanesulfonate, 2-nitrofluorene, 4-nitro-1,2 -phenylene diamine, and sodium azide served as positive control compounds for testing the bacteria in all three studies. 2-Aminoanthracene was used for testing the bacteria and the activity of the S-9 preparation. The positive controls showed normal reversion properties of all strains and good metabolic activity of the S-9 mix used. Thus, all three studies are considered to be valid.

With and without addition of S-9 as the metabolizing system, did not show any mutagenic activity in the Salmonella typhimurium strains at the concentration range used.

The test item dose-dependently increased the number of revertants of both, E. coli WP2 and WP2 uvrA. The effects were reproduced in the repeated experiments performed. Maximal increases of 3- to 5-fold over the respective solvent controls were induced. These effects however occurred at high test material concentrations which strongly precipitated on the agar plates.
In the third study conducted, this weak mutagenicity in E. coli strains was confirmed. However, with and without addition of S9-Mix as the external metabolizing system, no increases in the number of revertants over the respective solvent controls occurred with the purified test material. Thus, the test item was not mutagenic under the experimental conditions described. It is therefore very likely that chemical impurities are responsible for the mutagenic effects seen with the earlier tested batch.

In conclusion, the test item was weakly mutagenic in Escherichia coli WP2 and WP2 uvrA. Since the effects occurred at precipitating test material concentrations, it should however be noted that not the test item itself but, more likely, impurities may be responsible for the weak mutagenic effects found in this finding. This is confirmed by negative findings obtained with a purified batch tested.

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