Phenol, 4-methyl-, reaction products with dicyclopentadiene and isobutylene

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:

27 October - 5 November, 1986

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study is performed according to OECD Guideline 471 and under GLP conditions. No relevant deviations reported.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Phenol, 4-methyl-, reaction products with dicyclopentadiene and isobutylene

EC Number:

271-867-2

EC Name:

Phenol, 4-methyl-, reaction products with dicyclopentadiene and isobutylene

Cas Number:

68610-51-5

Molecular formula:

C10H12.C7H8O.C4H8

IUPAC Name:

2-(8-{3-[8-(3-tert-butyl-2-hydroxy-5-methylphenyl)tricyclo[5.2.1.0²,⁶]decan-4-yl]-2-hydroxy-5-methylphenyl}tricyclo[5.2.1.0²,⁶]decan-4-yl)-6-[4-(3-tert-butyl-2-hydroxy-5-methylphenyl)tricyclo[5.2.1.0²,⁶]decan-8-yl]-4-methylphenol

Details on test material:

-Name of test material (as cited in study report): Wingstay L
- Substance type: off-white powder
- Physical state: solid
- Analytical purity: not stated in report
- Impurities (identity and concentrations): not stated in report
- Composition of test material, percentage of components: not stated in report
- Purity test date: not stated in report
- Lot/batch No.: 809191 sample 8048-112-1
- Expiration date of the lot/batch: not stated in report
- Stability under test conditions: not stated in report

Method

Target gene:

Histidine gene in S. Typhimurium

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1538

Metabolic activation:

with and without

Metabolic activation system:

S9

Test concentrations with justification for top dose:

Prescreen test: 0, 10, 33, 67, 100, 333, 667, 1000, 3330, 6670, 10000 µg/plate (TA 100, with and without S9)
Mutation test: 0, 333, 667, 1000, 3330, 6670, 10000 µg/plate (all strains, with and without S9, two independent experiments)

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: highest possible dose preparation

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

yes

Positive controls:

yes

Positive control substance:

other: sodium azide, 2-nitrofluorene, 2-amino anthracene, ICR-191

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 hours

NUMBER OF REPLICATIONS: one pre-screen test in duplicate, mutation assay in tripicate, two independent experiments

DETERMINATION OF CYTOTOXICITY
- Method: counting of revertant colonies and evaluation of bacterial background lawn

Evaluation criteria:

Strains TA98 and TA100:
For a test article to be considered positive, it must cause at least a 2-fold increase in the mean revertants per plate of at least one tester strain over the mean vehicle control value for that tester strain. This increase in the mean number of revertants per plate must be accompanied by a dose response to increasing concentrations of the test article.

Strains TA1535, TA1537 and TA1538:
For a test article to be considered positive, it must cause at least a 3-fold increase in the mean revertants per plate of at least one tester strain over the mean vehicle control value for that tester strain. This increase in the mean number of revertants per plate must be accompanied by a dose response to increasing concentrations of the test article.

Statistics:

Not mentioned, see evaluation criteria.

Results and discussion

Test results

Test results 1

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:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: above 333 µg/plate

RANGE-FINDING/SCREENING STUDIES:
Prescreen study:
Dose levels to be tested in the mutagenicity assay were selected based on the results of the dose rangefinding study conducted on the test article using tester strain TA100 in both the presence and absence of S9. Ten dose levels of test article, from 10,000 to 10.0 µg/plate plate were tested. No cytotoxicity was observed in either the presence or absence of S9 as evidenced by no observed decrease in the number of revertants per plate and no thinning of the bacterial background lawn.

Mutation assay:
The data are presented as mean revertants per plate ± standard deviation for each treatment and control group and as individual plate counts. In two independent experiments all data were acceptable and no positive increases in the number of histidine revertants per plate were observed with any of the tester strains either in the presence or absence of S9. All criteria for a valid study were met.

COMPARISON WITH HISTORICAL CONTROL DATA:
All positive and negative control values were within historical limits.

Any other information on results incl. tables

none

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

The results of the Salmonella/Mammalian-Microsome Reverse Mutation Assay (Ames Test) indicate that in two independent experiments Wingstay L, did not cause a positive increase in the number of histidine revertants per plate of any of the tester strains either in the presence or absence of microsomal enzymes prepared from Aroclor-induced rat liver.