ethynyl cyclopropane

Endpoint summary

Additional information

Valid experimental data were available to assess the genetic toxicity in vitro and in vivo.

 

Gene mutation in bacteria

Ethynyl cyclopropane was not mutagenic in a standard plate Ames test with and without metabolic activation according to OECD guideline 473 (tested up to 10 % dilution in the standard plate test (SPT) with Salmonella typhimurium TA1535, TA 1537, TA 98, TA 100 and E.coli WP2; metabolic activation: liver S-9 mix from Aroclor-induced male Sprague-Dawley rats). A bacteriotoxic effect was observed under all test conditions. Under the experimental conditions chosen, Ethynyl cyclopropane did not show any mutagenic activity in the bacterial reverse mutation test on Salmonella typhimurium and E.coli in the presence and absence of a metabolic activation system, with both the plate incorporation method.

 

Gene mutation in mammalian cells

Actually, there is no information available.

 

Cytogenicity in mammalian cells

In addition to the gene mutation tests in bacteria, Ethynyl cyclopropane was investigated for cytogenicity in primary human lymphocytes according to OECD guideline 473. When incubated at dilutions up to 20 % (20 h harvest time) with these cells in absence of an artificial metabolic activation system (liver S-9 mix from Aroclor-induced rats) significant increase in the frequency of cells with structural chromosomal aberrations was noted while no increase in the frequency of cells with structural chromosomal aberrations was found in the presence of metabolic activation. Under the experimental conditions, the test item (Ethynyl cyclopropane did induce chromosome aberrations in cultured human lymphocytes.

 

Other studies

Actually, there is no information available.

 

Cytogenicity in vivo

Based on the results of the in vitro cytogenicity test, Ethynyl cyclopropane was investigated for genotoxic activity in vivo using the rat micronucleus test. Animals were treated with a single oral administration of the test substance at dose levels of 500, 1000 and 2000 mg/kg bodyweight. Bone marrow smears were obtained from five male and five female animals in the negative control, each of the test substance groups and the positive control group 24 hours after dosing. In addition, bone marrow smears were obtained from five male and five female animals in the negative control and high level treatment groups 48 hours after dosing. One smear from each animal was examined for the presence of micronuclei in 2000 immature erythrocytes. The proportion of immature erythrocytes was assessed by examination of at least 1000 erythrocytes from each animal. A record of the incidence of micronucleated mature erythrocytes was also kept. Rats treated with the test substance did not show any significant increase in the frequency of micronucleated immature erythrocytes at either sampling time. There was no significant decrease in the proportion of immature erythrocytes after treatment of the animals with the test substance. Ethynyl cyclopropane did not cause any significant increase in the incidence of micronucleated immature erythrocytes or any significant decrease in the proportion of immature erythrocytes relative to the vehicle control. Therefore, it is concluded that Ethynyl cyclopropane did not show any evidence of causing chromosome damage or bone marrow cell toxicity when administered at levels of up to 2000 mg/kg orally by gastric intubation in this in vivo test procedure.

Short description of key information:
Gene mutation in bacteria
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E.coli WP2 uvrA with and without metabolic activation (Ames test): negative (DuPont Merck, 1997) (standard plate test)

Gene mutation in mammalian cells
Actually, there is no information available.

Cytogenicity in mammalian cells
human lymphocytes with and without metabolic activation (Chromosome aberration test): positive (DuPont Merck, 1997).

Cytogenicity in vivo
rat micronucleus test: negative (DuPont Merck, 1997).

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

The test substance was not genotoxic in in vitro experiments using bacteria but demonstrated clear cytogenic effects in human lymphocytes in vitro when incubated in absence of an artificial external metabolic activation system. In vivo Ethynyl cyclopropane demonstrated no cytogenic effects in the rat micronucleus test.. Therefore, based on the information currently available, there is no need for classification of Ethynyl cyclopropane for mutagenic effects according to the criteria defined by the EU and the GHS system.