Dodecahydro-3,8,8,11a-tetramethyl-5H-3,5a-epoxynaphth[2,1-c]oxepin

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

June 5, 1997 to July 28, 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

rel-(3S,5aR,7aR,11aR,11bS)-3,8,8,11a-tetramethyldodecahydro-5H-3,5aepoxynaphtho[2,1-c]oxepine

Molecular formula:

C18H30O2

IUPAC Name:

rel-(3S,5aR,7aR,11aR,11bS)-3,8,8,11a-tetramethyldodecahydro-5H-3,5aepoxynaphtho[2,1-c]oxepine

Constituent 2

Reference substance name:

rel-(3R,5aS,7aR,11aR,11bS)-3,8,8,11a-tetramethyldodecahydro-5H-3,5aepoxynaphtho[2,1-c]oxepine

Cas Number:

220432-47-3

Molecular formula:

C18H30O2

IUPAC Name:

rel-(3R,5aS,7aR,11aR,11bS)-3,8,8,11a-tetramethyldodecahydro-5H-3,5aepoxynaphtho[2,1-c]oxepine

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
Code: Ro 84-4472/000
Name (as stated in the report): Amberketal
Lot No.: 007806
Appearance: white powder
Purity: 98.9% (major peak)
Expiry date:18/04/97

Method

Target gene:

Histidine gene of S. typhimurium

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Details on mammalian cell type (if applicable):

Not applicable

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

S9-mix

Test concentrations with justification for top dose:

The insolubility of the test compound limited the evaluable maximal dose to 1580 µg/plate.
The concentration range 15.8 to 1580 µg/plate was evaluated in the main experiments.

Vehicle / solvent:

Ro 84-4472/000 was dissolved in ethanol.

Controls

Controls 1

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Controls 2

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: ICR 191

Controls 3

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Controls 4

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

mitomycin C

Controls 5

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Details on test system and experimental conditions:

Solvents: MMC was dissolved in deionized water. All other positive control compounds were dissolved in dimethylsulfoxide. Stock solutions of the positive control compounds were dispensed in 1.5 ml micro test tubes (Eppendorf, Fed. Rep. of Germany) and kept in the deep freezer. The response was verified for each frozen batch.

Results and discussion

Test results

Key result

Species / strain:

other: S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: see additional information on results field below

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

Toxic effects were not apparent except for some reduction of background growth in strains TA1535, TA100 and TA102 at the concentration of 158 µg/plate in presence of S9. At the higher concentrations precipitation made evaluation of the background growth impossible, but the stability of the mutant colony numbers indicated absence of a strong cytotoxic activity of the compound even at the maximal dose of 1580 µg/plate.

Applicant's summary and conclusion

Conclusions:

The test compound did not induce any dose related increase of the number of revertant colonies/plate in any of the five tester strains.
Thus it can be concluded that Ro 84-4472/000 is devoid of mutagenic activity in the Ames test under the described experimental conditions.

Executive summary:

Ro 84-4472/000 (Amberketal) was evaluated for mutagenic activity in the Ames test. Two independent standard plate incorporation assays were performed in absence and in presence of an exogenous metabolic activation system (S9). FiveSalmonella typhimuriumtester strains (TA1535, TA97, TA98, TA100, and TA102) were employed. The activity of the S9-mix and the responsiveness of the tester strains were verified by includingappropriatecontrolsintoeachexperiment.Ro 84-4472/000 was dissolved in ethanol. The insolubility of the test compound limited the evaluable maximal dose to 1580 µg/plate. No indication for toxic effects were observed in a preliminary toxicity experiment . Therefore the concentration range 15.8 to 1580 µg/plate was evaluated in the main experiments. Due to the considerably more pronounced precipitation in the preincubation version of the assay the repeat experimentwasalsoperformedaccordingtotheplateincorporationmethod.

No increase in the number of revertant colonies was apparent for any of the five tester strains after treatment with Ro 84-4472/000.

Thus it can be concluded that neither Ro 84-4472/000 per se, nor any of the metabolites formed under the described experimental conditions used is mutagenic in the Amestest.