Levomenol

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

23 May 1995 - 10 July 1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

only 4 strains tested

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

1983

Deviations:

yes

Remarks:

only 4 strains tested

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

(R*,R*)-α,4-dimethyl-α-(4-methyl-3-pentenyl)cyclohex-3-ene-1-methanol

EC Number:

208-205-9

EC Name:

(R*,R*)-α,4-dimethyl-α-(4-methyl-3-pentenyl)cyclohex-3-ene-1-methanol

Cas Number:

515-69-5

Molecular formula:

C15H26O

IUPAC Name:

6-methyl-2-(4-methylcyclohex-3-en-1-yl)hept-5-en-2-ol

Test material form:

liquid

Details on test material:

Name of the test substance used in the study report: (+/-) alpha-Bisabolol

Method

Target gene:

His

Species / strain

Species / strain / cell type:

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

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254 induced rat liver S9

Test concentrations with justification for top dose:

20 - 5000 µg/plate (standard plate test)
2.5 - 1500 µg/plate (preincubation test)

Vehicle / solvent:

- Vehicle/solvent used: DMSO

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene (2-AA), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 4-nitro-o-phenylendiamine (NOPD), 9-aminoacridine chloride monohydrate (AAC)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation) and preincubation

DURATION
- Preincubation period: 20 min

NUMBER OF REPLICATIONS: tested in triplicates in 4 independent experiments

DETERMINATION OF CYTOTOXICITY
- Method: counting numbers of revertants + background lawn

Evaluation criteria:

In general, a substance to be characterized as positive in the Ames test has to fulfill the following requirements:
- doubling of the spontaneous mutation rate (control)
- dose-response relationship
- reproducibility of the results

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:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 4

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: No test substance precipitation was observed.

Any other information on results incl. tables

Table: 1^st Experiment Standard Plate Test (average results of 3 plates, respectively)

Concentration	TA 1535		TA 100		TA 1537		TA 98
	-S9	+S9	-S9	+S9	-S9	+S9	-S9	+S9
Vehicle	15	22	138	132	11	11	30	42
20 µg test item/plate	15	22	155	152	8	15	29	46
100 µg test item/plate	13	20	63	134	4	12	25	29
500 µg test item/plate	11	6	3	43	1	5	20	24
2500 µg test item/plate	0	1	0B	3	0	4	7	19
5000 µg test item/plate	0B	0B	0B	2	0B	5	7	13
5.0 µg MNNG/plate	1955		1494
2.5 µg 2-AA/plate		126		1802		169		935
100 µg AAC/plate					417
10 µg NOPD/plate							1155

 

  Table: 2^nd Experiment Standard Plate Test (average results of 3 plates, respectively)

Concentration	TA 1535		TA1537		concentration	TA 100
	-S9	+S9	-S9	+S9		-S9	+S9
Vehicle	22	18	10	12	Vehicle	151	141
250 µg test item/plate	15	17	6	4	50	137	144
500 µg test item/plate	8	14	5	3	100	85	148
750 µg test item/plate	10	8	2	4	200	69	105
1000 µg test item/plate	1	1	2	2	300	57	82
1500 µg test item/plate	0	1	2	5	400	52	90
MNNG	914					483
2-AA		92		184			1719
AAC			305

 

Table: 3^rd Experiment Preincubation Test (average results of 3 plates, respectively)

Concentration	TA 1535		Concentration	TA 100		Concentration	Ta 1537		TA 98
	-S9	+S9		-S9	+S9		-S9	+S9	-S9	+S9
Vehicle	14	19	Vehicle	114	108	Vehicle	8	13	27	29
45 µg test item/plate	0B	16	25 µg test item/plate	106	124	90 µg test item/plate	0B	0B	10	24
90 µg test item/plate	0B	14	50 µg test item/plate	0B	113	180 µg test item/plate	0B	0B	2	0B
180 µg test item/plate	0B	11	100 µg test item/plate	0B	91	360 µg test item/plate	0B	0B	0B	0B
360 µg test item/plate	0B	5	200 µg test item/plate	0B	62	750 µg test item/plate	0B	0B	0B	0B
750 µg test item/plate	0B	3	400 µg test item/plate	0B	44	1500 µg test item/plate	0B	0B	0B	0B
5.0 µg MNNG/plate	1275		5.0 µg MNNG/plate	1356		5.0 µg MNNG/plate
2.5 µg 2-AA/plate		83	2.5 µg 2-AA/plate		892	2.5 µg 2-AA/plate		82		1223
100 µg AAC/plate			100 µg AAC/plate			100 µg AAC/plate	426
10 µg NOPD/plate			10 µg NOPD/plate			10 µg NOPD/plate			1402

 

Table: 4^th Experiment Preincubation Test (average results of 3 plates, respectively)

Concentration	TA 1535		TA 100		Concentration	TA 1537		TA 98
	-S9	+S9	-S9	+S9		-S9	+S9	-S9	+S9
Vehicle	16	16	107	98	Vehicle	10	9	51	50
2.5 µg test item/plate	14	16	112	104	5 µg test item/plate	11	10	49	45
5 µg test item/plate	9	13	123	93	10 µg test item/plate	5	9	46	36
10 µg test item/plate	9	14	106	104	20 µg test item/plate	5	10	57	30
20 µg test item/plate	13	14		86	40 µg test item/plate	0B	8	53	32
40 µg test item/plate	0B	15		92	80 µg test item/plate	0B	7	54	42
5.0 µg MNNG/plate	847		679		5.0 µg MNNG/plate
2.5 µg 2-AA/plate		84		594	2.5 µg 2-AA/plate		84		420
100 µg AAC/plate					100 µg AAC/plate	439
10 µg NOPD/plate					10 µg NOPD/plate			958

2 -AA: 2-aminoanthracene

MNNG: N-methyl-N'-nitro-N-nitrosoguanidine

NOPD: 4-nitro-o-phenylendiamine

AAC: 9-aminoacridine chloride monohydrate

B: reduced his- background growth

 

Applicant's summary and conclusion

Conclusions:

The test substance was considered to be non-mutagenic with and without metabolic activation in bacteria.

Executive summary:

The test substance was tested for its mutagenic potential based on the ability to induce reverse mutations in selected loci in several strains of Salmonella typhimurium in the Ames test according to OECD guideline 471.

The Salmonella typhimurium strains used were TA 1535, TA 100, TA 1537 and TA 98. Two series of a standard plate test and two series of a preincubation test were performed. The dose range was 20 -5000 µg/plate for the standard plate tests and 2.5 - 1500 µg/plate for the preincubation tests. All tests were performed with and without metabolic activation (Aroclor induced rat liver S9).

No precipitation of the test substance was found. A bacteriotoxic effect (reduced his- background growth, decrease in the number of his+ revertants) was observed under the experimental conditions. An increase in the number of his+ revertants was not observed both in the standard plate test and in the preincubation test either with or without S-9 mix. According to the results of the present study, the test substance is not mutagenic in the Ames test.