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Toxicological information

Genetic toxicity: in vitro

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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)

Data source

Reference
Title:
Unnamed
Year:
2008

Materials and methods

Test guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
2-methylresorcinol
EC Number:
210-155-8
EC Name:
2-methylresorcinol
Cas Number:
608-25-3
Molecular formula:
C7H8O2
IUPAC Name:
2-methylbenzene-1,3-diol

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102
Metabolic activation:
with and without
Metabolic activation system:
rat S9 fraction
Test concentrations with justification for top dose:
33 to 5000 microgram/plate
Vehicle / solvent:
ethanol

Results and discussion

Test results
Species / strain:
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:
not determined
Additional information on results:
The Ames-test was performed with Salmonella typhimurium strains TA98, TA100, TA102,
TA1535 and TA1537 with and without fortified rat liver post-mitochondrial fraction (S9 mix)
induced with phenobarbital and β-naphthoflavone. The substance was tested in ethanol (>99%) at
six concentrations in the range of 33 to 5,000 μg/plate. This range was based upon the
results of a pre-experiment. The main assay was performed in two independent
experiments both with and without liver microsomal activation. A direct plate incorporation
assay as well as a pre-incubation experiment as the second run of the main test were
performed. Sodium azide (10 μg/plate) served as a positive control for TA100 and TA1535,
4-nitro-o-phenylene-diamine (10 μg/plate) for TA1537 and TA98 and methyl methane
sulfonate (4 μg/plate) for TA102 without S9 mix. The enzyme activity of S9 mix was
separately controlled by testing with 2-aminoanthracene (2.5 μg/plate) in all tester strains.
The solvent ethanol and the untreated fresh cell suspension served as negative controls.

Results
Irregular background growth was observed at 5000 μg/plate in strain TA1537 without S9
mix and in strain TA102 with S9 mix in the second experiment. Toxic effects, evident as a
reduction in the number of revertants, were observed in strain TA1537 without S9 mix in
experiment I, and in strains TA1537, TA98, and TA100 with S9 mix and strains TA98 and
TA102 without S9 mix in experiment II. No substantial increase in revertant colony numbers
of any of the five tester strains was observed following treatment with the substance at any dose
level, either in the presence or absence of metabolic activation. There was also no tendency
of higher mutation rates with increasing concentrations in the range below the generally
acknowledged border of biological relevance. The positive controls used showed a distinct
increase of induced revertant colonies.

Conclusion
The substance was not considered to be mutagenic in the in vitro bacterial mutagenicity test in the
presence or absence of S9 mix.

Applicant's summary and conclusion