Reaction mass of (2R,7aR)-2,4,6,6-Tetramethyl-7,7a-dihydro-1,3-benzodioxol-5(6H)-one and (2S,7aS)-2,4,6,6-Tetramethyl-7,7a-dihydro-1,3-benzodioxol-5(6H)-one

Genetic toxicity: in vitro

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:

other: GLP compliant guideline study, available as unpublished report, restriction in design (no E.coli WP2 or S.typhimurium TA 102 used and only one positive control used to test efficacy of the S9-mix), but adequate for assessment

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:

, no E.coli WP2 or S.typhimurium TA 102 used and only one positive control used to test efficacy of the S9-mix

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

162691-58-9

EC Number:

605-300-0

Cas Number:

162691-58-9

IUPAC Name:

162691-58-9

Details on test material:

- Name of the test substance used in the study report: Asta-C9-Acetal
- Appearance, consistency: Yellowish liquid
- Stability under test conditions: The stability of the test substance throughout the study period has been proven by reanalysis.
- Storage : Refrigerator (protected from light)

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:

Aroclor induced rat liver S-9 mix

Test concentrations with justification for top dose:

- Experiment 1 and 2: 20, 100, 500, 2500, 5000 µg/plate

Vehicle / solvent:

DMSO

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

with S-9 mix for all strains

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: N-methyl-N'-nitro-N-nitrosoguanidine

Remarks:

without S-9 mix for strains 100 and TA 1535

Controls 3

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenylendiamine

Remarks:

without S-9 mix for strain TA 98

Controls 4

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 9-aminoacridine chloride monohydrate

Remarks:

without S-9 mix for strain TA 1537

Details on test system and experimental conditions:

EXPERIMENT 1
- METHOD OF APPLICATION: in agar (plate incorporation)
- DURATION: Exposure duration: 48 - 72 h
- NUMBER OF REPLICATIONS: 3 test plates per dose or per control
- DETERMINATION OF CYTOTOXICITY: Toxicity detected by a reduced his- background growth, decrease in the number of his+ revertants

EXPERIMENT 2 and 3
- METHOD OF APPLICATION: preincubation
- DURATION: Preincubation period: 20 min; Exposure duration: 48 - 72 h
- NUMBER OF REPLICATIONS: 3 test plates per dose or per control
- DETERMINATION OF CYTOTOXICITY: Toxicity detected by a reduced his- background growth, decrease in the number of his+ revertants

Evaluation criteria:

In general, a substance to be characterized as positive in the Ames test has to fulfill the following requirements:
- doubling of the spontaneous mutation rate (control)
- dose-response relationship
- reproducibility of the results

Results and discussion

Test results

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

A bacteriotoxic effect was observed only in the preincubation test from about 500 µg/plate onward (TA 1535) or at doses ≥2500µg/ plate (TA 100, TA 1537, TA 98).
No test substance precipitation was found.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

According to the results of the present study, the test substance is not mutagenic in the Ames test under the experimental conditions chosen here.

Executive summary:

In a GLP compliant mutagenicity test, performed according to OECD guideline 471, 4 Salmonella typhimurium strains (TA 1535, TA 1537, TA 98, and TA 100) were used to test the mutagenic potential of the test substance both with and without metabolic activation. Two experiments were performed; a standard plate test and preincubation test, respectively. In both tests, bacteria were exposed to 0, 20, 100, 500, 2500, and 5000 µg test substance/plate. No precipitation of the test substance was found. A bacteriotoxic effect was observed only in the preincubation test from about 500 µg/plate onward (TA 1535) or at doses ≥ 2500 µg/ plate (TA 100, TA 1537, TA 98). An increased in the number of his+ revertants was not observed in the standard plate test or in the preincubation test either without S9 mix or after the addition of a metabolizing system. It was therefore concluded that the test substance is not mutagenic under these experimental conditions.