Isopropenyl acetate

Endpoint summary

Additional information

A study according to OECD 476 was performed to investigate the potential of Isopropenyl acetate to induce gene mu­tations at the HPRT locus in V79 cells of the Chinese hamster.The assay was performed in two independent experiments, using two parallel cultures each. The first main experiment was performed with and without liver microsomal activation (S9) and a treatment period of 4 hours.The second experiment was performed with a treatment time of 4 hours with and 24 hours without metabolic activation.The highest concentration of the test item was 1000 µg/mL equal to approximately 10 mM. The tested concentrations were 62.5, 125, 250, 500, 750 and 1000µg/mL for both experiments with and without metabolic activation. The treatment times were 4 hours (1st experiment; 2nd experiment with metabolic activation) and 24 hours (2nd experiment without metabolic activation) respectively.No substantial and reproducible dose dependent increase of the mutation frequency was observed in both main experiments. Appropriate reference mutagens, used as positive controls, induced a distinct increase in mutant colonies and thus, showed the sensitivity of the test item and the activity of the metabolic activation system.n conclusion it can be stated that under the ex­perimental conditions reported the test item did not induce gene mutations at the HPRT locus in V79 cells.Therefore, Isopropenyl acetate is considered to be non-mutagenic in this HPRT assay. 

Isopropenyl acetate was examined for mutagenic activity in five strains of Salmonella typhimurium both in the -absence and in the presence of a metabolic activation system (S-9 mix), in compliance with OECD guideline 471 ("Salmonella typhimurium, Reverse Mutation Assay").From the results obtained in both experiments it appeared that incubation of the test substance with the bacteria did not increase the number of his+ revertants with S. typhimurium TA 1535, TA 1537, TA 1538, TA 98 or TA 100, either in the absence or in the presence of the S-9 mix. At the highest dose level used (100. 0 mg/plat e ) the test substance appeared to be (slightly) toxic for all strains, as was seen from a diminished background lawn of bacterial growth and/or a strong reduction of the number of his+ revertants as compared with the controls. The positive controls used in the present assays gave the expected strong increase in the number of his+ revertants, both in the absence and in the presence of the S-9 mix.

From the above findings it is concluded that Isopropenyl acetate did not show mutagenic activity in Salmonella typhimurium TA 1535 , TA 1537, TA 1538, TA 98 or TA 100 either in the absence or in the presence of the S-9 mix, under the conditions employed in this evaluation.

 

Isopropenyl acetate was also investigated for clastogenicity in the in vitro mammalian chromosome aberration assay on Chinese Hamster V79 cells according to OECD Guideline 473. The test was performed with and without metabolic activation (S9 mix). In both experiments with and without metabolic activation 1001.16 µg/ml corresponding to 10 mM was selected as highest dose group for the microscopic analysis of chromosomal aberrations. The chromosomes were prepared20 h after start of the treatment with the test item. The treatment intervals were 4 h (1^stexperiment, with/without metabolic activation, 2^ndexperiment with metabolic activation) and 20 h (2^ndexperiment without metabolic activation). The tests were run in duplicate. No precipitation or cytotoxicity was observed in any of the experiments. The number of aberrant cells found in the treatment groups did not show a biologically relevant increase as compared to the corresponding negative control. No biologically relevant increase in the frequencies of polyploidy cells was found after treatment with the test item. The positive controls used worked as expected. In conclusion during the described in vitro chromosomal aberration test and under the conditions reported, the test item Isopropenyl acetate did not induce structural chromosomal aberrations in th eV79 Chinese hamster cell line. Therefore the test item is considered to be non-clastogenic.

Isopropenyl acetate was assessed in the micronucleus assay according to OECD Guideline 474 for its potential to induce micronuclei in polychromatic erythrocytes (PCE) in the bone marrow of the mouse. The test article was formulated in deionised water. Deionized water was used as vehicle control. The volume administered orally was 10 ml/kg b.w.. 24 h and 48 h after a single administration of the test article the bone marrow cells were collected for micronuclei

analysis. Ten animals (5 males, 5 females) per test group were evaluated for the occurrence of micronuclei. 2000 polychromatic erythrocytes (PCE) per animal were scored for micronuclei.

To describe a cytotoxic effect due to the treatment with the test article the ratio between polychromatic and normochromatic erythrocytes (NCE) was determined in the same sample and reported as the number of NCE per 2000 PCE.

The following dose levels of the test article were investigated:

24 h preparation interval: 200, 670, and 2000 mg/kg b.w..

48 h preparation interval: 2000 mg/kg b.w..

The highest guideline-recommended dose (2000 mg/kg) was estimated by pre-experiments to be suitable. The animals expressed Slight toxic reactions. The mean number of normochromatic erythrocytes was not increased after treatment with the test article as compared to the mean value of NCEs of the vehicle control, indicating that isopropenyl acetate had no cytotoxic properties in the bone marrow. In comparison to the corresponding vehicle controls there was no statistically significant or biologically relevant enhancement in the frequency of the detected micronuclei at any preparation interval and dose level after administration of the test article. The mean values of micronuclei observed after treatment with Isopropenyl acetate were below the value of the vehicle control group. 40 mg/kg b.w. cyclophosphamide administered per os was used as positive control which showed a statistically significant increase of induced micronucleus frequency. In conclusion, it can be stated that during the study described and under the experimental conditions reported, the test article did not induce micronuclei as determined by the micronucleus test in the bone marrow cells of the mouse.

 

Short description of key information:
Isopropenyl acetate did not show a mutagenic potential in the ames test, an in vitro chromosomal abberation test in mammalian cells nor in the HPRT test with or without metabolic activation. It is also negative in the Mouse Micronucleus assay in vivo

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Isopropenyl acetate did not show a mutagenic potential in the ames test, an in vitro chromosomal abberation test in mammalian cells nor in the HPRT test with or without metabolic activation. It is also negative in the Mouse Micronucleus assay in vivo. Therefore it is not classified as to the endpoint mutagenicity.