[No public or meaningful name is available]

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05 January 2018 to 29 June 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

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:

Fatty acids, C18-unsatd., dimers

Cas Number:

61788-89-4

Molecular formula:

C36H64O4 (representative)

IUPAC Name:

Fatty acids, C18-unsatd., dimers

Constituent 2

Reference substance name:

Fatty acids, tall-oil

Cas Number:

61790-12-3

Molecular formula:

C18H32O2 (representative)

IUPAC Name:

Fatty acids, tall-oil

Constituent 3

Reference substance name:

1H-Imidazole-1-ethanol, 4,5-dihydro-, 2-nortall-oil alkyl derivs.

Cas Number:

61791-39-7

Molecular formula:

C22H40N2O (representative)

IUPAC Name:

1H-Imidazole-1-ethanol, 4,5-dihydro-, 2-nortall-oil alkyl derivs.

Test material form:

liquid

Specific details on test material used for the study:

Purity: >95%
Description: Clear viscous blackish orange liquid
Storage: Room temperature, protected from light

Method

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 98

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1535

Species / strain 3

Species / strain / cell type:

S. typhimurium TA 100

Species / strain 4

Species / strain / cell type:

S. typhimurium TA 1537

Species / strain 5

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254-induced rat liver S9 was purchased from MolTox

Test concentrations with justification for top dose:

15.0, 50.0, 150, 500, 1500 and 5000 µg per plate, based upon limited toxicity at 5000 µg per plate

Vehicle / solvent:

Tetrahydrofuran

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

methylmethanesulfonate

other: 2-aminoanthracene

Details on test system and experimental conditions:

Five bacterial strains were treated in triplicate with the test material, both in the absence and presence of an S9 metabolic activation system at doses of 15.0, 50.0, 150, 500, 1500 and 5000 µg per plate using the plate incorporation method. The plates were incubated for 48 to 72 hours at 37±2 °C prior to evaluation.

Rationale for test conditions:

In the preliminary toxicity assay, the dose levels tested were 3.70, 10.0, 33.3, 37.0, 100, 333, 370, 1000, 3333 and 5000 µg per plate. Precipitate was observed beginning at 1000 µg per plate with all conditions. Toxicity as reduction in revertant count was observed beginning at 3333 or at 5000 µg per plate with few conditions. Based upon these results, the maximum dose tested in the mutagenicity assay was 5000 µg per plate.

Evaluation criteria:

For each replicate plating, the mean and standard deviation of the number of revertants per plate were calculated and are reported.

For the test substance to be evaluated positive, it must cause a dose-related increase in the mean revertants per plate of at least one tester strain over a minimum of two increasing concentrations of test substance as specified below:

Strains TA1535 and TA1537
Data sets were judged positive if the increase in mean revertants at the peak of the dose response was equal to or greater than 3.0-times the mean vehicle control value and above the corresponding acceptable vehicle control range.

Strains TA98, TA100 and WP2 uvrA
Data sets were judged positive if the increase in mean revertants at the peak of the dose response was equal to or greater than 2.0-times the mean vehicle control value and above the corresponding acceptable vehicle control range.
An equivocal response is a biologically relevant increase in a revertant count that partially meets the criteria for evaluation as positive. This could be a dose-responsive increase that does not achieve the respective threshold cited above or a non-dose responsive increase that is equal to or greater than the respective threshold cited. A response was evaluated as negative if it was neither positive nor equivocal.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 4

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 5

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

The study was concluded to be negative without conducting a confirmatory (independent repeat) assay because the results were clearly negative; hence, no further testing was warranted.

Executive summary:

The test material was tested to evaluate its mutagenic potential by measuring its ability to induce reverse mutations at selected loci of several strains ofSalmonellatyphimuriumand at the tryptophan locus ofEscherichia colistrain WP2 uvrA in the presence and absence of an exogenous metabolic activation system. Tetrahydrofuran (THF) was used as the vehicle.

In the preliminary toxicity assay, the dose levels tested were 3.70, 10.0, 33.3, 37.0, 100, 333, 370, 1000, 3333 and 5000 µg per plate. Precipitate was observed beginning at 1000 µg per plate with all conditions. Toxicity as reduction in revertant count was observed beginning at 3333 or at 5000 µg per plate with few conditions. Based upon these results, the maximum dose tested in the mutagenicity assay was 5000 µg per plate.

In the mutagenicity assay, the dose levels tested were 15.0, 50.0, 150, 500, 1500 and 5000 µg per plate. No toxicity was observed. Precipitate was observed beginning at 1500 µg per plate with all conditions. No positive mutagenic responses were observed with any of the tester strains in either the presence or absence of S9 activation.

These results indicate the test material was negative for the ability to induce reverse mutations at selected loci of several strains ofSalmonellatyphimuriumand at the tryptophan locus ofEscherichia colistrain WP2 uvrA in the presence and absence of an exogenous metabolic activation system.