(E)-3-methyl-5-cyclopentadecen-1-one

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:

From 2005-06-1 to 2005-08-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study performed according to OECD test guideline No. 471 and in compliance with GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

21 July 1997

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Deviations:

no

Principles of method if other than guideline:

not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

Inspected on 2nd December 2002. Signed on 13 February 2003.

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

(5E)-3-Methyl-5-cyclopentadecen-1-one

Cas Number:

101151-17-1

Molecular formula:

C16 H28 O

IUPAC Name:

(5E)-3-Methyl-5-cyclopentadecen-1-one

Constituent 2

Reference substance name:

(5Z)-3-Methyl-5-cyclopentadecen-1-one

Cas Number:

21944-94-5

Molecular formula:

C16 H28 O

IUPAC Name:

(5Z)-3-Methyl-5-cyclopentadecen-1-one

Constituent 3

Reference substance name:

(4E)-3-Methyl-4-cyclopentadecen-1-one

Cas Number:

62221-84-5

Molecular formula:

C16 H28 O

IUPAC Name:

(4E)-3-Methyl-4-cyclopentadecen-1-one

Test material form:

liquid

Details on test material:

- Physical state: colourless liquid
- Storage condition of test material: ca. 4°C under nitrogen in the dark

Method

Target gene:

Histidine gene for Salmonella and tryptophan gene for E.coli

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

S9 fraction from Sprague-Dawley rats treated with phenobarbitone/-naphtoflavone

Test concentrations with justification for top dose:

Preliminary toxicity test: 0, 0.15, 0.5, 1.5, 5, 15, 50, 150, 500, 1500 and 5000 μg/plate.
Range-finding test: 50, 150, 500, 1500 and 5000 μg/plate.
Main test: 50, 150, 500, 1500 and 5000 μg/plate.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: test substance immiscible in water. Well known solvent/vehicle not reacting with the test substance.

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Remarks:

See table 7.6.1/1

Positive control substance:

4-nitroquinoline-N-oxide

9-aminoacridine

N-ethyl-N-nitro-N-nitrosoguanidine

Remarks:

Without S9-mix

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Remarks:

See table 7.6.1/1

Positive control substance:

benzo(a)pyrene

other: 2-aminoanthracene

Remarks:

With S9-mix

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: ca. 48 hours at 37°C

NUMBER OF REPLICATIONS: triplicate plates per dose level

DETERMINATION OF CYTOTOXICITY
- Method: growth assessment of the bacterial background lawn

OTHER EXAMINATIONS:
- Other: Observations of precipitate of the test substance

OTHER: ACCEPTANCE CRITERIA: The reverse mutation assay was considered valid if the following criteria were met:
1. All tester strain cultures exhibit a characteristic number of spontaneous revertants per plate in the vehicle and untreated controls (according to historical control 2003 & 2004).
2. The appropriate characteristics for each tester strain have been confirmed, eg rfa cell-wall mutation and pKM101 plasmid R-factor etc.
3. All tester strain cultures should be in the approximate range of 1 to 9.9 billion bacteria per ml.
4. Each mean positive control value should be at least two times the respective vehicle control value for each strain, thus demonstrating both the intrinsic sensitivity of the tester strains to mutagenic exposure and the integrity of the S9-mix.
5. There should be a minimum of four non-toxic test material dose levels.
6. There should be no evidence of excessive contamination.

Rationale for test conditions:

Tested up to limit concentrations

Evaluation criteria:

Dose-related increase in revertant frequency over the dose range tested and/or reproducible at one or more concentrations in at least one bacterial strain with or without metabolic activation.
A test material will be considered non-mutagenic (negative) in the test system if the above criteria are not met.

Statistics:

none

Results and discussion

Test results

Key result

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

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

True negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: not applicable
- Effects of osmolality: not applicable
- Evaporation from medium: Test material vapour pressure (0.04 Pa) is too low to expect a significant effect of evaporation on test results. Test material is not classified as volatile according to the criteria of the Directive 1999/13/EC.
- Water solubility: Test material was solubilized in DMSO to improve solubility
- Precipitation: a precipitate (oily in appearance) was observed at and above 1500 µg/plate, this did not prevent the scoring of revertant colonies.
- Other confounding effects: none

RANGE-FINDING/SCREENING STUDIES: the test material was non-toxic to the strains of bacteria used (TA100 and WP2uvrA-).

COMPARISON WITH HISTORICAL CONTROL DATA: All tester strain cultures exhibit a characteristic number of spontaneous revertants per plate in the vehicle and positive controls. The comparison was made with the historical control ranges for 2003 and 2004 of the corresponding Testing Laboratory.

ADDITIONAL INFORMATION ON CYTOTOXICITY: the test material caused no visible reduction in the growth of the bacterial background lawn at any dose level, although slight decreases in revertant colony frequency were noted to several of the Salmonella strains at the upper dose level

Remarks on result:

mutagenic potential (based on QSAR/QSPR prediction)

Any other information on results incl. tables

Preliminary toxicity Test:

The test material was non-toxic to the strains of bacteria used (TA100 and WP2uvrA-). The test material formulation and S9-mix used in this experiment were both shown to be sterile.

 

The number of revertant colonies for the preliminary toxicity test were:

Metabolic Activation	Strain	Dose (μg/plate)
		0	0.15	0.5	1.5	5	15	50	150	500	1500	5000
-	TA100	133	120	141	138	142	136	133	120	107	120P	107P
+	TA100	87	82	98	94	113	87	94	126	89	80P	76P
-	WP2uvrA-	21	18	18	22	15	22	25	20	17	25P	16P
+	WP2uvrA-	29	15	21	24	17	13	18	22	26	22P	27P

Mutation test:

Results for the negative controls (spontaneous mutation rates) are presented in Table 1 (See Graphs & Tables of results in “Attached background material”) and were considered to be acceptable. These data are for concurrent untreated control plates performed on the same day as the Mutation Test.

The individual plate counts, the mean number of revertant colonies and the standard deviations for the test material, vehicle and positive controls both with and without metabolic activation, are presented in Table 2 to Table 5 (See Graphs & Tables of results in "Attached background material").

The test material caused no visible reduction in the growth of the bacterial background lawn although a slight decrease in the frequency of revertant colonies was noted to the majority of the Salmonella strains at the upper dose levels. The test material was, therefore, tested up to the maximum recommended dose level of 5000ug/plate. A precipitate (oily in appearance) was observed at and above 1500ug/plate, this did not prevent the scoring of revertant colonies.

No significant increases in the frequency of revertant colonies were recorded for any of the bacterial strains, at any dose level either with or without metabolic activation.

All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies thus confirming the activity of the S9-mix and the sensitivity of the bacterial strains.

Applicant's summary and conclusion

Conclusions:

The test item is not mutagenic with and without metabolic activation in S. thyphimurium strains TA1535, TA1537 TA98 & TA100, and E.coli WP2 uvrA-.

Executive summary:

In a reverse gene mutation assay performed according to the OECD test guideline No. 471 and in compliance with GLP, S. typhimurium strains TA 1535, TA 1537, TA 98 and TA 100 and E.coli strain WP2 uvrA^- were exposed the test material diluted in DMSO both in the presence and absence of a metabolic activation system (10% liver S9 in standard co-factors) using the plate incorporation method. The dose range for the range-finding test was determined in a preliminary toxicity assay and was 15 to 5000 µg/plate. The experiment was repeated on a separate day using the same dose range as the range-finding test, fresh cultures of the bacterial strains and fresh test material formulations.

The vehicle (dimethyl sulphoxide) control plates gave counts of revertant colonies within the normal range. All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies, both with or without metabolic activation. Thus, the sensitivity of the assay and the efficacy of the S9-mix were validated.

The test material caused no visible reduction in the growth of the bacterial background lawn although slight decrease in the frequency of revertant colonies was noted to the majority of the Salmonella strains at the upper dose levels. The test material was, therefore, tested up to the maximum recommended dose level of 5000 µg/plate. A precipitate (oily in appearance) was observed at and above 1500 µg/plate, this did not prevent the scoring of revertant colonies.

No significant increases in the frequency of revertant colonies were recorded for any of the bacterial strains, at any dose level either with or without metabolic activation.

 

Under the test condition, the test material is not mutagenic with and without metabolic activation in S. thyphimurium strains TA1535, TA1537 TA98 & TA100, and E.coli WP2 uvrA^-.

This study is considered as acceptable and satisfies the requirement for the reverse gene mutation endpoint.