Isopentyl propionate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Data is from publication.

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, 1984

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: as per mentioned below

Principles of method if other than guideline:

Reverse mutation assays using S. typhimurium strains TA92, TA1535, TA100, TA1537, TA94 and TA98 were carried out according to the method of Ames, McCann & Yamasaki.

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Isopentyl propionate

EC Number:

203-322-1

EC Name:

Isopentyl propionate

Cas Number:

105-68-0

Molecular formula:

C8H16O2

IUPAC Name:

3-methylbutyl propanoate

Details on test material:

Name of test material (as cited in study report): Isoamyl Propionate
Substance type: Organic
Physical state: Liquid
Supplied from Japan Food Additives Association, Tokyo, at the request of the Ministry of Health and Welfare of Japan.

Specific details on test material used for the study:

Name of test material (as cited in study report): Isoamyl Propionate
Substance type: Organic
Physical state: Liquid
Supplied from Japan Food Additives Association, Tokyo, at the request of the Ministry of Health and Welfare of Japan.

Method

Target gene:

Histidine

Species / strain

Species / strain / cell type:

S. typhimurium, other: Salmonella Typhirium TA92, TA1535, TA100, TA1537, TA94 and TA98

Details on mammalian cell type (if applicable):

Not applicable

Additional strain / cell type characteristics:

not specified

Cytokinesis block (if used):

not specified

Metabolic activation:

with and without

Metabolic activation system:

S-9 was prepared from the liver of Fischer rats ( pretreated 5 days before with polychlorinated biphenyls (500 mg/kg body weight of Kanechlor KC-400 in olive oil, ip).

Test concentrations with justification for top dose:

0.1 – 10 mg/plate

Vehicle / solvent:

Solvent used: DMSO
Justification for choice of solvent/vehicle: Since the chemical was insoluble in water

Controls

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

not specified

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium; in agar (plate incorporation); preincubation; in suspension; as impregnation on paper disk
: pre incubation

DURATION
Preincubation period: Cells cultured overnight were pre-incubated with both the test sample and the S-9 mix for 20 min at 37°C before plating. The number of revertant (his +) colonies was scored after incubation at 37°C for 2 days
Exposure duration: 2 days

NUMBER OF REPLICATIONS: Duplicate plates were used for each of six different concentrations of the sample.

Rationale for test conditions:

Not specified

Evaluation criteria:

The test result was considered to be negative.if there were no significant increases in the numbers of revertant colonies detected in any S. typhimurium strains at the maximum dose.

Statistics:

Yes

Results and discussion

Test results

Species / strain:

S. typhimurium, other: Salmonella Typhimurium TA92, TA1535, TA100, TA1537, TA94 and TA98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Additional information on results:

The liver microsome fraction (S-9) was prepared from the liver of Fischer rats (Charles River Japan Co.) pretreated 5 days before with polychlorinated biphenyls (500 mg/kg body weight of Kanechlor KC-400 in olive oil, ip). The reaction mixture (S-9 mix) contained 5 mM-glucose 6-phosphate, 4mM-NADPH, 4mM-NADH, 33mM-KC1, 8 mM-MgCI 2, 100 mM-phosphate buffer (pH 7.4) and 3.75 ml S-9 (129 mg protein) in a total volume of 12.5 ml.

Remarks on result:

other: No mutagenic effect were observed.

Applicant's summary and conclusion

Conclusions:

Isoamyl Propionate (105-68-0) was evaluated for its mutagenic potential.A negative result indicates that no significant increases in the number of revertant colonies were detected in any S. typhimurium strains at the maximum dose.The test chemical was tested by the AMES test using 6 strains of S.typhimurium.At the maximum dose of 10mg/plate, the test chemical was non mutagenic

Executive summary:

This report presents data from primary screening by the Ames test on 200 food additives used in Japan for Isoamyl Propionate (105-68-0).The samples were supplied from the Japan Food Additives Association, Tokyo, at the request of the Ministry of Health and Welfare of Japan, where the purity and quality of each sample were checked.

Reverse mutation assays usingS. typhimuriumstrains TA92, TA1535, TA100, TA1537, TA94 and TA98 were carried out at the concentraton of 0.1 – 10 mg/plate in the presence and absence of S9 .Acetone was used as a solvent since test compound is insoluble in water.All samples were kept in a refrigerator before use.Reverse mutation assays usingS. typhimuriumstrains TA92, TA1535, TA100, TA1537, TA94 and TA98 were carried out according to the method of Ames, McCann & Yamasaki.All these test strains were originally provided by Dr B. N. Ames, University of California, Berkeley, USA. The liver microsome fraction (S-9) was prepared from the liver of Fischer rats (Charles River Japan Co.) pretreated 5 days before with polychlorinated biphenyls (500 mg/kg body weight of Kanechlor KC-400 in olive oil, ip). The reaction mixture (S-9 mix) contained 5 mM-glucose 6-phosphate, 4mM-NADPH, 4mM-NADH, 33mM-KCl, 8 mM-MgCI₂, 100 mM-phosphate buffer (pH 7.4) and 3.75 ml S-9 (129 mg protein) in a total volume of 12.5 ml. Cells cultured overnight were pre-incubated with both the test sample and the S-9 mix for 20 min at 37°C before plating. Duplicate plates were used for each of six different concentrations of the sample.The number of revertant (his +) colonies was scored after incubation at 37°C for 2 days. The result was considered positive if the number of colonies found was twice the number in the control (exposed to the appropriate solvent or untreated). A negative result indicates that no significant increases in the number of revertant colonies were detected in anyS. typhimuriumstrains at the maximum dose.At the maximum dose of 10mg/plate, the test chemical was non mutagenic. Therefore Isoamyl Propionate was considered to be non mutagenic in AMES test..Hence the test chemical cannot be classified as gene mutant in vitro.