Registration Dossier

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

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: Adequate for assessment.

Data source

Reference
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:
1996
Bibliographic source:
Environmental Mutagenesis (1986) Vol 8 (7), 1-119

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
neither Salmonella TA102 or E.coli strain included (but not considered to invalidate the assay)
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Cyclohexane
EC Number:
203-806-2
EC Name:
Cyclohexane
Cas Number:
110-82-7
Molecular formula:
C6H12
IUPAC Name:
cyclohexane

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:
Arochlor 1254-induced rat and hamster metabolic activation system
Test concentrations with justification for top dose:
0.000 (solvent control), 10.000, 33.000, 100.000, 333.000, 1000.000, 3333.000, 10000.000 µg per plate
Vehicle / solvent:
dimethyl sulfoxide (DMSO) or distilled water (0.05 ml vehicle with 0.5 ml S-9 mix and 0.05 ml overnight culture)
Controls
Negative solvent / vehicle controls:
yes
True negative controls:
yes
Remarks:
potassium chloride
Positive controls:
yes
Remarks:
sodium azide for TA1535 and TA100, 4-nitro-o-phenylenediamine for TA98, 9-aminoacridine for TA97 and TA1537, 2-aminoanthracene was used with all strains with hamster and rat liver metabolic activation systems
Details on test system and experimental conditions:
Cyclohexane was assayed for mutagenicity in the pre-incubation assay. Concurrent solvent and positive controls were tested with and without the metabolic activation systems. At least five dose levels of the chemicals were tested, with three plates per dose level.

METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 20 minutes at 37°C
- Exposure duration: 48 hour at 37°C

NUMBER OF REPLICATIONS: 2

DETERMINATION OF CYTOTOXICITY
- one or more of the following phenomena: appearance of his pinpoint colonies, reduced numbers of revertant colonies per plate, or thinning or absence of the bacterial lawn
Evaluation criteria:
The criteria used for data evaluation are summarised as follows: 1) mutagenic response: a dose-related, reproducible increase in the number of revertants over background, even if the increase was less than twofold; 2) non-mutagenic 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.

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:
not specified
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Only results for cyclohexane presented in summary
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 with metabolic activation
negative without metabolic activation

Cyclohexane negative with and without metabolic activation
Executive summary:

This publication reported Salmonella mutagenicity tests on 270 chemicals (including cyclohexane) tested under contract to the National Toxicology Program.  Cyclohexane was tested using S. typhimurium strains TA 1535, TA 1537, TA 98 and TA 100 in the presence and absence of metabolic activation (S9). The study was run using 2 independent repeats.

There was no significant increase in the numbers of revertant colonies in any strain both with and without metabolic activation. The results indicate that cyclohexane is not mutagenic in this bacterial assay.