3,5,5-trimethylcyclohex-2-enone

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

Study period:

study is part of a 13-week study (May 1979 - August 1979) and a 2-year carcinogenesis study (January 1980 - January 1982)

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Salmonella mutagenicity tests: II. results from the testing of 270 chemicals

Author:

Mortelmans K, Haworth S, Lawlor T, Speck W, Tainer B and Zeiger E

Year:

1986

Bibliographic source:

Environ. Mutagen. Suppl. 8, 1-119

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

1986

Report date:

1986

Materials and methods

Principles of method if other than guideline:

Method: see: Haworth S, Lawlor T, Mortelmans K, Speck W and Zeiger E (1983).  Salmonella mutagenicity test results for 250 chemicals. Environ 
Mutagen.  5 (Suppl. 1), 3 -142.

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

3,5,5-trimethylcyclohex-2-enone

EC Number:

201-126-0

EC Name:

3,5,5-trimethylcyclohex-2-enone

Cas Number:

78-59-1

Molecular formula:

C9H14O

IUPAC Name:

3,5,5-trimethylcyclohex-2-enone

Details on test material:

other TS: Origin: Leidy Chemical Corporation 97 % pure, 0.3 % water

Method

Target gene:

mutated gene loci responsible for histidine auxotrophy

Species / strain

Species / strain / cell type:

other: Salmonella typhimurium TA98, TA100, TA1535, TA1537

Details on mammalian cell type (if applicable):

Species/cell type: from Dr. B. Ames, Univ. of California

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254-induced rat and hamster liver  fractions

Test concentrations with justification for top dose:

33, 100, 333, 1000, 3333 and 10000 (TA 1535), 100, 333, 1000, 3333, 10000 (TA 100), 33, 100, 333, 1000, 3333 (TA 98 and 1537) µg/plate

Vehicle / solvent:

water

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

water

True negative controls:

yes

Remarks:

potassium chloride

Positive controls:

yes

Remarks:

for details see below

Positive control substance:

other: for details see below

Remarks:

no remarks

Details on test system and experimental conditions:

Type: Ames test
ADMINISTRATION: 
- Number of replicates: 3 per dose level, repeated
- Positive and negative control groups and treatment:    
sodium azide positive for TA 1535 and TA 100, 4-nitro-o-phenylenediamine positive for TA 98, 9-aminoacridine positive for TA 97 and TA 1537,  
2-aminoanthracene positive all strains, potassium chloride negative
- Solvent: H2O
- 3 investigations were performed: 1. without MA, 2. with MA (Arochlor-1254 liver rats) 3. with MA (Arochlor-1254 liver hamster)

Cells and test compound or solvent (water) were incubated for 20 minutes at 37 °C in the presence of either S9 or buffer (0.1 M PO4, pH 7.4).
After the addition of soft agar, the contents of each tube were poured onto 25 ml of minimal glucose bottom agar. When the top agar had solidified,
the plates were inverted and incubated at 37 °C for 48 hours (Haworth et al. 1983).  The analysis was performed twice, each in triplicate.

Evaluation criteria:

1. mutagenic response: a dose-related, reproducible increase in the number of revertants over background, even if the increase was less than
twofold
2. nonmutagenic response: when no increase in the number of revertants was elicited by the chemical
3. questionable response: when there was an absence of a clear-cut-dose-related increase in revertants; when the dose-related increases in the
number of revertants were not reproducible; or when the response was of insufficient magnitude to support a determination of mutagenicity.

Statistics:

not reported

Results and discussion

Test results

Species / strain:

other: Salmonella typhimurium TA98, TA100, TA1535, TA1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: -S9: TA 100, 1535, 98 >=1000, TA 1537 >= 3333 µg/plate, +S9 (rat and hamster): only TA 1535 = 10000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

GENTOXIC EFFECTS:
- With metabolic activation: None (even at cytotoxic concentrations)
- Without metabolic activation: None (even at cyctotoxic concentrations)

CYTOTOXIC CONCENTRATION:
TA 98: >= 1000 µg/plate (-S9)
TA 100: >= 1000 µg/plate (-S9)
TA 1535: >= 1000 µg/plate (-S9); 1000 µg/plate (+S9)
TA 1537: >= 3333 µg/plate (-S9)

Remarks on result:

other: other: Salmonella typhimurium TA98, TA100, TA1535, TA1537

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

no remarks

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

Under the conditions of this study, Isophorone was not mutagenic in strains TA 100, TA 1535, TA 1537, or TA 98 of Salmonella typhimurium in the
presence or absence of Aroclor 1254-induced Sprague-Dawley male rat or male Syrian hamster liver S9.

Executive summary:

The test substance Isophorone was tested for any mutagenic activity in the Ames Salmonella/microsomes test. Four histidine-

auxotrophic Salmonella typhimurium strains TA 98, TA 100, TA 1535, and TA1537 were treated with the test item by the pre-incubation method. Dose levels covering a total range of 33 to 10000 µg/plate, in triplicate both with and without the addition of a metabolising system (Aroclor induced rat and hamster liver S9 mix) were employed.

A mutagenic activity of Isophorone to any of the five tester strains was not observed with and without metabolic activation. It is therefore concluded, that Isophorone is not a bacterial mutagen.