3,7-dimethyloct-6-en-1-yn-3-ol

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:

experimental study

Adequacy of study:

key study

Study period:

05/04/1993 -28/05/1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test was conducted according to OECD Test Guideline No. 474, 1987, under GLP Standards, and QA.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

no

Principles of method if other than guideline:

Not relevant

GLP compliance:

yes

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

3,7-dimethyloct-6-en-1-yn-3-ol

EC Number:

249-482-6

EC Name:

3,7-dimethyloct-6-en-1-yn-3-ol

Cas Number:

29171-20-8

Molecular formula:

C10H16O

IUPAC Name:

3,7-dimethyloct-6-en-1-yn-3-ol

Details on test material:

- Name of test material (as cited in study report): DL-Dehydrolinalool
- Physical state: liquid
- Storage condition of test material: Room temperature

Test animals

Species:

mouse

Strain:

other: Füllinsdorf Moro Albino SPF, outbred strain

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Biological Research Laboratories Ltd., CH-4414 Füllinsdorf
- Weight at study initiation: females: 36.7 g, males: 42.8 g (mean)
- Assigned to test groups randomly: yes
- Housing: Fully-airconditioned animal room under periodic bacteriological control; Macrolon cages containing saw dust (males individually, females three)
- Diet (e.g. ad libitum): Complete rodent maintenance diet ad libitum
- Water (e.g. ad libitum): Tap water in drinking bottles ad libitum
- Acclimation period: one week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2
- Humidity (%): 55 ± 10
- Air changes (per hr): 20-25 cylcles
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: Rape seed oil
- Concentration of test material in vehicle: (volume) 50, 100, 200 mg/ml

Details on exposure:

No data

Duration of treatment / exposure:

24 hours after application animals of all dosage groups were sacrificed. In addition, 48 and 72 hours after application, the animals of a negative
control group and of the highest dose were sacrificed.

Frequency of treatment:

Once (single dose treatment)

Post exposure period:

24 hours after application animals of all dosage groups were sacrificed. In addition, 48 and 72 hours after application, the animals of a negative
control group and of the highest dose were sacrificed.

Doses / concentrations

Remarks:

Doses / Concentrations:
500, 1000, 2000 mg/kg bw
Basis:
actual ingested
gavage

No. of animals per sex per dose:

500 and 1000 mg/kg bw: 5 male and 5 female animals
2000 mg/kg bw: 18 male and 18 female animals
Negative control: 15 males and 15 females
Positve control: 5 males and 5 females

Control animals:

yes, concurrent vehicle

yes, historical

Positive control(s):

Procarbazine hydrochloride
- Route of administration: orally
- Doses / concentrations: 50 mg/kg bw

Examinations

Tissues and cell types examined:

Bone-marrow; polychromatic erythrocytes (PCE)/normochromatic erythrocytes (NCE)

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION: The dose of 2000 mg/kg is the highest applicable one as determined by preliminary experiments (maximum
tolerated dose) and the limit dose according to the guideline.

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): three different sampling times (24, 48, 72 hours) after oral administration of the high dose (2000 mg/kg) and one sampling time (24 hours) for the lower doses (500 and 1000 mg/kg).

DETAILS OF SLIDE PREPARATION: Four bone-marrow smears per animal were prepared. Two smears per animal were air-dried, fixed and stained with May-Grünwald-Giemsa. After completion of the evaluation the other slides were discarded.

METHOD OF ANALYSIS: 1000 polychromatic erythrocytes (PCE) per animal were checked for the existence of micronuclei. The ratio of polychromatic
to normochromatic erythrocytes (PCE/NCE) was determined on 1000 counts of erythrocytes. The micronucleated normochromatic erythrocytes (MN-NCE) were recorded while counting the 1000 PCE per animal and the frequency of MN-NCE was calculated as well. For the positive control only 500 cells were taken into account.

Evaluation criteria:

The test compound will be considered negative if:
- The rate of micronucleated polychromatic erythrocytes (MN-PCE) is not statistically significantly increased and
- The rate of MN-PCE falls within the normal range of the historical controls.
The test compound will be considered positive if:
- The rate of MN-PCE is statistically significantly increased at any dose or sampling time and
- The rate of MN-PCE exceeds the normal range of historical controls.
The biological relevance of the results always needs to be carefully discussed. In particular if only one of the two above mentioned criteria are met, the final evaluation will be assessed on a case by case basis.

Statistics:

The observed yields of micronucleated polychromatic erythrocytes (MN-PCE) were evaluated by means of the Mann-Whitney-U-Test.

Results and discussion

Test results

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Remarks:

3 of 36 animals of the top dose died; reduced PCE/NCE ratio at top dose

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Dose range: 1000 and 2000 mg/kg
- Clinical signs of toxicity in test animals: No deaths were recorded but the animals exhibited clinical signs of toxicity in terms of reduced motility.
Consequently 2000 mg/kg was chosen as the top dose in the main experiment. In the main experiment 3 out of 36 animals died after administration
of this dose.

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): DL-Dehydrolinalool did not statistically significantly raise the frequency of micronucleated
polychromatic erythrocytes (MN-PCE).
- Ratio of PCE/NCE (for Micronucleus assay): The PCE/NCE ratio was slightly reduced after administration of the high dose (2000 mg/kg), at the 24 h sampling time, which indicates moderate bone marrow toxicity and provides evidence that the target cells were exposed to the test compound.
- Appropriateness of dose levels and route: 3 out of 36 animals in the top dose group (2000 mg/kg) died, indicating that it would not have been
possible to administer the test compound at an appreciably higher dose.

Any other information on results incl. tables

No relevant

?????

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
DL-Dehydrolinalool did not raise the frequency of micronucleated polychromatic erythrocytes (MN-PCE) and therefore no chromosome-breaking or spindle disturbances producing activity was demonstrated at any of the sampling times. It can be concluded that under the experimental conditions
described in this report DL-Dehydrolinalool does not show genotoxic activity in mouse bone marrow cells.

Executive summary:

DL-Dehydrolinalool was evaluated as to its ability to induce chromosome breakage or spindle disturbances in vivo using the micronucleus assay in mouse bone marrow.

Doses of 500,1000 and 2000 mg/kg bodyweight were evaluated. The test compound was administered by oral gavage. The highest dose tested was the maximum tolerated dose. A slight antiproliferative effect on bone marrow cells in terms of a reduction of the PCE/NCE ratio was observed at the 24 hours sampling time in the top dose group, indicating that the target cells were exposed to the test compound.

Bone marrow smears from three different sampling times (24, 48, 72 hours) were evaluated after oral administration of the high dose (2000 mg/kg) and one sampling time (24 hours) was evaluated for the lower doses (500 and 1000 mg/kg).

DL-Dehydrolinalool did not raise the frequency of micronuclei-containing polychromatic erythrocytes (MN-PCE) and therefore no chromosome-breaking or spindle disturbances producing activity was demonstrated at any of the sampling times.

The sensitivity of the test system was demonstrated by using procarbazine hydrochloride as a positive control substance. It increased the number of micronucleated polychromatic erythrocytes significantly.

It can be concluded that under the experimental conditions described in this report DL-Dehydrolinalool does not show genotoxic activity in mouse bone marrow cells.