Sodium 1-(3,4-dihydro-6-methyl-2,4-dioxo-2H-pyran-3-ylidene)ethanolate

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Circa 1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference

Reference Type:

publication

Title:

Micronucleus test in mice on 39 food additives and eight miscellaneous chemicals

Author:

Hayashi et al

Year:

1988

Bibliographic source:

Fd. Chem. Toxic. 26, No. 6, 487-500

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Micronucleus test conducted on a Japanese government laboratories: National Institute of Hygiene Sciences and Public Health Laboratory.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Sodium 1-(3,4-dihydro-6-methyl-2,4-dioxo-2H-pyran-3-ylidene)ethanolate

EC Number:

224-580-1

EC Name:

Sodium 1-(3,4-dihydro-6-methyl-2,4-dioxo-2H-pyran-3-ylidene)ethanolate

Cas Number:

4418-26-2

Molecular formula:

C8H7O4.Na

IUPAC Name:

sodium 1-(6-methyl-2,4-dioxo-2H-pyran-3(4H)-ylidene)ethanolate

Test animals

Species:

mouse

Strain:

other: ddy - from a Japanese breeder

Details on species / strain selection:

Used by the laboratories

Sex:

male

Details on test animals or test system and environmental conditions:

Eight-week-old male ddY mice (Shizuoka Agri-cultural Cooperative Association for Laboratory Animals, Shizuoka) were used at both laboratories, and were allowed food pellets CE-2 (Japan Clea, Tokyo) and water ad lib. throughout the experiments.

Administration / exposure

Route of administration:

other: Oral and intraperitoneal

Vehicle:

water or normal saline

Details on exposure:

See any other information on materials and methods below::

Duration of treatment / exposure:

See any other information on materials and methods below:

Frequency of treatment:

Multiple (four or five) injections with 24-hr intervals between the injections.

Post exposure period:

24 hours

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

See results for route of exposure for dosages

Doses / concentrations 2

Dose / conc.:

37.5 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

62.5 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

75 mg/kg bw/day (nominal)

Doses / concentrations 5

Dose / conc.:

125 mg/kg bw/day (nominal)

Doses / concentrations 6

Dose / conc.:

150 mg/kg bw/day (nominal)

Doses / concentrations 7

Dose / conc.:

250 mg/kg bw/day (nominal)

Doses / concentrations 8

Dose / conc.:

300 mg/kg bw/day (nominal)

Doses / concentrations 9

Dose / conc.:

500 mg/kg bw/day (nominal)

Doses / concentrations 10

Dose / conc.:

1 000 mg/kg bw/day (nominal)

Doses / concentrations 11

Dose / conc.:

1 250 mg/kg bw/day (nominal)

No. of animals per sex per dose:

2-6/group for the pilot and main test

Control animals:

yes, concurrent no treatment

Positive control(s):

Mitomycin C.
Additionally a number of substances were tested in this study, some of which were suspected to be genotoxic.

Examinations

Tissues and cell types examined:

See any other information on materials and methods below:

Details of tissue and slide preparation:

See any other information on materials and methods below:

Evaluation criteria:

See any other information on materials and methods below:

Statistics:

A two-stage statistical procedure was used: the frequency of MNPCEs in each treatment group was compared with the binomial distribution specified by historical control data. In the second stage, the dose-response relationship was tested by the Cochran-Armitage trend test. A positive result was recorded only when one or more treatment group(s) showed a statistically significant difference (P <0.01) from the spontaneous level of MNPCEs and the trend test indicated a positive dose response (P < 0.05).

Results and discussion

Test results

Test results 1

Sex:

male

Genotoxicity:

positive

Toxicity:

not specified

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: intraperitoneal injection

Test results 2

Key result

Sex:

male

Genotoxicity:

negative

Toxicity:

not specified

Vehicle controls validity:

valid

Negative controls validity:

not valid

Positive controls validity:

valid

Remarks on result:

other: oral gavage

Additional information on results:

See attached table

Applicant's summary and conclusion

Conclusions:

Dehydroacetic acid, sodium salt DHA-Na, when dosed by oral gavage showed that there was no trend for genotoxicity. When dosed by the intraperitoneal route there was a positive trend for genotoxicity. However, as indicated in the OECD guideline 747, the appropriate route of exposure should be used, the appropriate route of potential exposure is most likely oral rather than intraperitoneal. The data therefore indicate that DHA-Na should be considered as not genotoxic.

Executive summary:

Dehydroacetic acid, sodium salt DHA-Na, when dosed by oral gavage, at dose levels between 37.5 and 1250 mg/kg showed that there was no positive trend for genotoxicity. When dosed by the intraperitoneal route there was a positive trend for genotoxicity. However, as indicated in the OECD guideline 747, the appropriate route of exposure should be used, the appropriate route of potential exposure is most likely oral rather than intraperitoneal.  The data therefore indicate that DHA-Na should be considered as not genotoxic.