(±)-neomenthol

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1984

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

publication

Title:

Primary mutagenicity screening of food additives currently used in Japan

Author:

M. Ishidate Jr, T. Sofuni, K. Yoshikawa, M. Hayashi, T. Nohmi, M. Sawada and A. Matsuoka

Year:

1984

Bibliographic source:

Fd Chem. Toxic. Vol. 22, No. 8, pp. 623-636

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: method of Ishidate & Odashima (1977)

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

GLP compliance:

not specified

Type of assay:

other: in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

Menthol

EC Number:

201-939-0

EC Name:

Menthol

Cas Number:

89-78-1

Molecular formula:

C10H20O

IUPAC Name:

2-isopropyl-5-methylcyclohexanol

Method

Species / strain

Species / strain / cell type:

other: Chinese Hamster Lung Fibroblast (CHL)

Details on mammalian cell type (if applicable):

The cell line was originally established from the lung of a newborn female at the Cancer Research Institute, Tokyo (Koyama, Utakoji & Ono, 1970), and was maintained by 4-day passages in Minimum Essential Medium (MEM; GIBCO) supplemented by 10% calf serum.
The modal chromosome number is 25 and the doubling time was approximately 15 hr.

Additional strain / cell type characteristics:

not specified

Metabolic activation:

without

Test concentrations with justification for top dose:

3 different concentrations tested but not specified in the publication.
The maximum dose of each sample was selected by a preliminary test in which the dose needed for 50% cell-growth inhibition was estimated using a cell densitometer (Monocellater, Olympus Co., Ltd).
Previous studies indicated that the osmotic pressure of the medium generally rose with sample concentrations of more than 10 mM, so that the maximum dose for some samples was limited to around this level, at which cytotoxic effects were not necessarily ubserved.

Vehicle / solvent:

Ethanol
No justification given

Controls

Untreated negative controls:

yes

Remarks:

untreated cultures

Negative solvent / vehicle controls:

yes

Remarks:

same treatment but exposed only to DMSO

True negative controls:

not specified

Positive controls:

not specified

Positive control substance:

not specified

Details on test system and experimental conditions:

The cells were exposed at three different doses for 24 and 48 hr. In the present study, no metabolic activation systems were applied.

Chromosome preparations were made as follows:
Colcemid (final concn 0.2 µg/ml) was added to the culture 2 hr before cell harvesting. The cells were then trypsinized and suspended in a hypotonic KCI solution (0.075 M) for 13 min at room temperature. After centrifugation the cells were fixed with acetic acid-methanol (1:3, vJv) and spread on clean glass slides. After air-drying, the slides were stained with Giemsa solution (1.5%, at pH 6.8; E. Merck) for 12-15 min. A hundred well-spread metaphases were observed under the microscope (x 600 with a no-cover objective lens). The incidence of polyploid cells as well as of cells with structural chromosomal aberrations such as chromatid or chromosome gaps, breaks, exchanges, ring formations, fragmentations and others, was recorded on each culture plate.

Untreated cells and solvent-treated cells served as negative controls, in which the incidence of aberrations was usually less than 3.0%.

Evaluation criteria:

The results were considered to be negative if the incidence was less than 4.9%, equivocal if it was between 5.0 and 9.9%, and positive if it was more than 10.0%.

Statistics:

no documentation available

Results and discussion

Test results

Species / strain:

other: Chinese Hamster Lung Fibroblast (CHL)

Metabolic activation:

without

Genotoxicity:

negative

Remarks:

at the highest non cytotoxic dose tested (0.2 mg/ml)

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

not specified

Additional information on results:

Percentage of structure aberrations after 48 hours: 4%
no further details available

Any other information on results incl. tables

no detailed table given

Applicant's summary and conclusion

Conclusions:

Interpretation of results: negative

The test material is not clastogenic under the used test conditions