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:
supporting study
Study period:
January 1979 to 29 December 1980
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: The test material contained components other than 1-phenylethyl hydroperoxide, therefore observed effects cannot be attributed to either 1-phenylethyl hydroperoxide or other components (ethyl benzene or other volatile componetnts).

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1981

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
not applicable
Principles of method if other than guideline:
The study followed the methodologies as in Ames et al., 1975 and is equivalent to the OECD TG 471 (adopted in July 1997).

Ames, B.N., McCann, J. and Yamasaki, E. (1975). Methods for Detecting Carcinogens and Mutagens with the Salmonella/Mammalian-Microsome Mutagenicity Test. Mutation Res., 31, 347-364.
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): EBHP plant stream samle (33.9% of ethyl benzene hydroperoxide (EBHP) in ethyl benzene).

- Analytical purity: 33.9%

- Composition of test material, percentage of components: ethylbenzene hydroperoxide plant stream 33.9%, acetophenone 2.95%, phenyl ethyl alcohol 2.40%, benzaldehyde 0.04%, phenol 0.23%, sodium 0.5% and acids (titration) 0.001% Meq/G.

- Purity test date: 28 June 1978.

- Lot/batch No.: 78/12484

- Stability : For at least 4 hours (in DMSO)

Method

Target gene:
Histidine operon (his) for Salmonella.
Tryptophan operon (trp) for E.Coli.
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium, other: S. typhimurium TA 1535, TA 1537, TA 1538, TA 98 and TA 100
Details on mammalian cell type (if applicable):
Not applicable
Additional strain / cell type characteristics:
not specified
Species / strain / cell type:
E. coli, other: E. coli WP2 and E. coli WP2 uvr A
Details on mammalian cell type (if applicable):
Not applicable
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
rat liver microsomal activation system
Test concentrations with justification for top dose:
0.0678, 0.678, 6.78, 67.8 and 678 µg of EBHP (final amounts of 0.2, 2, 20, 200 and 2000 µg of EBHP plant stream per plate) with or without S9.

Vehicle / solvent:
ethyl benzene (33.9% of ethyl benzene hydroperoxide (EBHP) in ethyl benzene)
Controlsopen allclose all
Untreated negative controls:
yes
Remarks:
(concurrent untreated control)
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
for S. typhimurium with or without S9

Migrated to IUCLID6: 20 µg
Untreated negative controls:
yes
Remarks:
(concurrent untreated control)
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: neutral red, 20 µg
Remarks:
for S. typhimurium with or without S9
Untreated negative controls:
yes
Remarks:
(concurrent untreated control)
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
for E. coli with or without S9

Migrated to IUCLID6: 20 µg
Untreated negative controls:
yes
Remarks:
(concurrent untreated control)
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
Remarks:
for E. coli with or without S9

Migrated to IUCLID6: 20 µg

Results and discussion

Test resultsopen allclose all
Species / strain:
other: S. typhimurium TA 1535, TA 1537, TA 1538, TA 98, TA 100 and E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not applicable
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Species / strain:
E. coli WP2
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not applicable
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Species / strain:
E. coli WP2
Metabolic activation:
without
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not applicable
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

See attachment tables for results.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
positive without metabolic activation In E. coli WP2

Application of the EBHP plant stream sample up to 2000 µg per plate did not consistently increase the reverse gene mutation rate of E. coli WP2 uvrA,
S. typhimurium TA 1535, TA 1537, TA 1538, TA 98, and TA I00 in vitro in the presence or absence of a rat liver S9 fmaction, but did result in an increase in the reverse mutation frequency in E. coli WP2 in the absence of the rat liver S9 fraction. Therefore the EBHP is considered to be a a weak
microbial mutagen in E. coli WP2 in the absence of S9 under the conditions of this test.

Executive summary:

The mutagenic activity of an EBHP plant stream sample was investigated in agar layer cultures of Salmonella typhimurium TA 1535, TA 1537, TA 1538, TA 98, TA 100, Escherichia coli WP2 and WP2 uvr both with and without the incorporation of a rat liver microsomal activation system.

Application of the EBHP plant stream sample up to 2000 µg per plate did not consistently increase the reverse gene mutation rate of E. coli WP2 uvrA,

S. typhimurium TA 1535, TA 1537, TA 1538, TA 98, and TA I00 in vitro in the presence or absence of a rat liver S9 fraction, but did result in an increase in the reverse mutation frequency in E. coli WP2 in the absence of the rat liver S9 fraction.

 

The results with the EBHP plant stream sample indicate that it is a weak microbial mutagen in E. coli WP2 in the absence of S9.

The test material contains only 33.9% of 1-phenylethyl hydroperoxide. There were not enough information to identify observed effects attributed to the substance, therefore a reliability of 3 is assigned.