(epoxyethyl)benzene

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: Acceptable, well documented publication which meets basic scientific principles

Data source

Reference

Reference Type:

publication

Title:

A study on the mutagenic activity of styrene and styrene oxide

Author:

Vainio H et al

Year:

1976

Bibliographic source:

Scand. j. work environ. & health 3 (1976) 147-151

Report date:

1976

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

no positive controls

GLP compliance:

no

Remarks:

study performed before implementation of GLP

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

(epoxyethyl)benzene

EC Number:

202-476-7

EC Name:

(epoxyethyl)benzene

Cas Number:

96-09-3

Molecular formula:

C8H8O

IUPAC Name:

2-phenyloxirane

Method

Species / strain

Species / strain / cell type:

S. typhimurium, other: TA1535, TA1537, TA1538, TA100 and TA98

Metabolic activation:

with and without

Metabolic activation system:

S9

Test concentrations with justification for top dose:

10 exp.-4 , 10 exp. -5, 10 exp. -6, 10 exp. -7 , 10 exp. –8 , 10 exp. –9, 0 mol / plate

Vehicle / solvent:

ethanol

Controls

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

no

Results and discussion

Test results

Species / strain:

S. typhimurium, other: TA1535, TA1537, TA1538, TA100 and TA98

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Additional information on results:

strains TA 1537 and TA 98 were tested negative

Remarks on result:

other: strain/cell type: TA 1535, TA 1538, TA 100

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
positive

The test compound was positive in three of five strains and is therfore regarded positive in the bacterial reverse mutation assay

Executive summary:

In a reverse gene mutation assay in bacteria, strains TA1535, TA1537, TA1538, TA100 and TA98 ofS. typhimuriumwere exposed to Styrene Oxide dissolved in ethanol at concentrations of 10 exp-4, 10 exp. -5, 10 exp. -6, 10 exp. -7 , 10 exp. –8 , 10 exp. –9, 0 mol / plate in the presence and absence of mammalian metabolic activation (liver S9 mix from rats induced with Clophen) using the co-incubation method. 

Styrene Oxide was tested up to cytotoxic concentrations (10 exp-4 mol/plate). In strain TA 1535, a dose related increase to 357 (without metabolic activation) and 484 (with metabolic activation) revertants vs. 20 and 45 revertants in control was observed. In strain TA 100, a dose related increase to 1111 (without metabolic activation) and 1165 (with metabolic activation) revertants vs. 84 and 135 revertants in control was observed.  There was a concentration related positive response of induced mutant colonies over background.

This study is classified as acceptable. This study satisfies the requirement for Test Guideline  OPPTS 870.5100¹; OECD 471 for in vitro mutagenicity (bacterial reverse gene mutation) data. The lack of a positive control is acceptable as the test compound is clearly positive and thus demonstrates adequate sensitivity of the test system.