L-menthol

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: According to ECVAM ToxRTool reliability 2. Missing: Purity of substance, clear description of study endpoints and their methods of determination only males mice used

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1993

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

yes

Remarks:

Study documentation with gaps

Principles of method if other than guideline:

Same principle as OECD 474, but not enough documentation available to certify a total compliance.

GLP compliance:

not specified

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

D-menthol

EC Number:

239-388-3

EC Name:

D-menthol

Cas Number:

15356-70-4

IUPAC Name:

2-isopropyl-5-methylcyclohexanol

Constituent 2

Reference substance name:

DL Menthol

IUPAC Name:

DL Menthol

Details on test material:

DL Menthol, CAS 15356-70-4 received from the NTP chemical repository (Radian Corporation, Austin, TX)

Test animals

Species:

mouse

Strain:

B6C3F1

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: NATIONAL TOXICOLOGY PROGRAM - TACONIC FARMS
- Age at study initiation: BETWEEN 9 AND 14 WEEKS
- Weight at study initiation: WITHIN 2 g RANGE OF MEAN WEIGHT BETWEEN 25 AND 33 g
- Assigned to test groups randomly: YES, JUST BEFORE EUTHANASIA

NO MORE DETAILS MENTIONNED

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

Corn Oil (from GIBCO, Grand Island, NY)

Details on exposure:

Intraperitoneal injections (0.4ml) of test chemical (or control) on 3 consecutive days.

Duration of treatment / exposure:

mice were injected ip on three consecutive days with either the test chemical , a weakly active dose of the positive control chemical or the vehicle. Mice were euthanized 24 hr after the third treatment

Frequency of treatment:

three injections on three consecutive days.

Post exposure period:

Mice euthanized with CO2 24 hours after the last injection.

Doses / concentrations

Remarks:

Doses / Concentrations:
0; 250; 500 and 1000 mg/kg, (based on a preliminary dose determination study taking into account mortality, solubility in solvent and depression in the percentage of bone marrow polychromatic erythrocytes)
Basis:
nominal conc.

No. of animals per sex per dose:

5 to 7 male mice per dose

Control animals:

yes, concurrent vehicle

Positive control(s):

- Substances used as positive control: 12-dimethylbenzanthracene (57-97-6); mitomycin C (50-07-7);
- Route of administration: intraperitoneal

Examinations

Tissues and cell types examined:

Bone marrow smears were examined;
2000 polychromatic erythrocytes per animal were scored

Details of tissue and slide preparation:

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields):
Two slides per mouse were prepared.

DETAILS OF SLIDE PREPARATION:
Bone marrow smears were fixed in absolute methanol, and stained with acridine orange.

METHOD OF ANALYSIS:
Slides were evaluated at 1000X magnification, using epi-illuminated fluorescence microscopy (450-490 nm excitation, 520 nm emission), for the number of Micronucleated-Polychromatic Erythrocytes (over a total of 2000 Polycrhomatic erythrocytes.

Evaluation criteria:

Significant increase in Micronucleated-Polychromatic Erythrocytes compared to negative control.

Statistics:

The data were analyzed using the Micronucleus Assay Data Management and Statistical software package (version 1.4), which was designed specifically for in vivo micronucleus data [JLS, 1990].
The level of significance was set at an alpha level of 0.05.
To determine whether a specific treatment resulted in a significant increase in Micronucleated-Polychromatic Erythrocytes (MN-PCE), the number of MN-PCE were pooled within each dose group and analyzed by a one-tailed trend test. In the software package used, the trend test incorporates a variance inflation factor to account for excess animal variability.
In the event that the increase in the dose response curve is nonmonotonic, the software program allows for the data to be analyzed for a significant positive trend after data at the highest dose only has been excluded. However, in this event, the alpha level is adjusted to 0.01 to protect against false positives.
The %PCE data were analyzed by an analysis of variance (ANOVA) test based on pooled data.
Pairwise comparisons between each group and the concurrent solvent control group was by an unadjusted one-tailed Pearson chisquared test which incorporated the calculated variance inflation factor for the study.

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

yes

Remarks:

only for the highest dose (1000 mg/kg)

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

See table below

Any other information on results incl. tables

Results summary:

	Micronucleus Induction					Toxicity
	Trend P value	Dose (mg/kg)	MN-PCE/Total PCE	Number of animal scored	Pair-wise comparison α = 0.05	Survival/Total Mice	% PCE
Menthol	0.374	0 250 500 1000	2.90 ± 0.43 3.60 ± 0.58 2.20 ± 0.34 3.67 ± 0.60	5 5 5 3	0.1922 0.8368 0.2025	5/5 5/5 5/5 3/6	54.5 64.2 56.7 51.8
Solvent control			2.38 ± 0.93
Positive Control   - DMBA   - Mitomycin c			7.93 ± 1.69 6.85 ± 2.26

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
Under the test conditions, the test substance does not produce more micronuclei in the polychromatic erythrocytes compared to vehicle control in male B6C3F1 mice.