2-phenylhexanenitrile

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

The substance is negative in the Ames test (OECD TG 471)

The substance is negative in the Chromosome aberration test (OECD TG 473)

The substance is negative in the Mouse Lymphoma Assay (OECD TG 476)

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Ames test

In this OECD TG 471 study, the mutagenic potential of Salicynalva, histidine dependent auxotrophic mutants of Salmonella typhimurium (strains TA 1535, TA 1537, TA 1538, TA 98 and TA 100) and a tryptophan dependent mutant of Escherichia coli (WP2 uvrA) were exposed to the test substance, diluted in dimethyl sulphoxide which was also used as a negative control. Two independent mutation tests were performed, in the presence and absence of liver preparations from Aroclor 1254-induced rats. In the preliminary toxicity test, with dose levels of up to 5000 µg/plate, toxicity was observed at the top dose level towards all the tester strains in the presence of S-9 mix and all the strains except TA 1535 and WP2 uvrA in the absence of S-9 mix. A top dose level of 5000 µg/plate was chosen for the subsequent mutation study. Other dose levels used in the mutation assays were: 2500, 1250, 625, 312.5, 156.25, 78.125 and 39.063 µg/plate. No evidence of mutagenic activity was seen at any dose level of Salicynalva in either mutation test. The concurrent positive control compounds demonstrated the sensitivity of the assay and the metabolising activity of the liver preparations. It is concluded that, when tested in dimethyl sulphoxide, Salicynalva was not mutagenic in this bacterial system.

Chromosomal aberrations

An OECD TG 473 study was performed to assess the ability of Salicynalva to induce chromosomal aberrations in human lymphocytes cultured in vitro. Cultured human lymphocytes, stimulated to divide by addition of phytohaemagglutainin, were exposed to the test substance both in the presence and absence of S9 mix derived from rat livers. Solvent and positive control cultures were also prepared. After the appropriate treatment time, cell division was arrested using colchicines, the cells harvested and slides prepared, so that metaphase figures could be examined for chromosomal damage. In order to assess the toxicity of Salicynalva to cultured human lymphocytes, the mitotic index was calculated for all cultures treated with the test substance and the solvent control. On the basis of these data, the following concentrations were selected for metaphase analysis:

First test: Without S9-mix; 18 hour harvest: 75, 63.5 and 31.25 µg/mL; With S9-mix; 18 hour harvest: 187.5, 125 and 62.5 µg/mL.

Second test: Without S9-mix; 18 hour harvest: 75, 31.25 and 15.6 µg/mL; With S9-mix; 18 hour harvest: 250, 187.5 and 125 µg/mL; Without S9-mix; 32 hour harvest: 75 µg/mL; With S9-mix; 32 hour harvest: 250 µg/mL.

There were no statistically significant increases in the number of aberrant cells, in the presence of S9 mix, at the 18 or 32 hour harvest. In the absence of S9-mix, in the second test at 18 hour harvest, there was a statistically significant increase in the number of aberrant cells at the lowest concentration, 15.6 µg/mL. However, this increase was only observed when gap damage was included and lies within the historical control range. There was no dose-response relationship and this increase was not seen in the first test or at the later sampling time. In addition, the mean frequency of aberrant cells in the solvent controls in this test was slightly low when compared with the average historical control values. Therefore it is concluded that this increase is not treatment related. All positive control compounds caused large, statistically significant increases in the proportion of aberrant cells. It is concluded that Salicynalva has shown no evidence of clastogenic activity in this in vitro cytogenetic test.

Mouse Lymphoma assay

The genotoxicity in mammalian cells was investigated using the mouse lymphoma assay according to OECD 476 guideline. The spontaneous mutation frequencies in the solvent-treated control cultures were between the minimum and maximum value of the historical control data range. The positive control chemicals, methyl methane sulfonate and cyclophosphamide induced appropriate responses. In the absence of S9-mix, Salicynalva did not induce a significant increase in the mutation frequency in the first experiment. This result was confirmed in an independent repeat experiment with modifications in the duration of treatment time. In the presence of S9-mix, Salicynalva did not induce a significant increase in the mutation frequency in the first experiment. This result was confirmed in an independent repeat experiment with modifications in the concentration of the S9 for metabolic activation. Therefore Salicynalva is considered to be non-genotoxic in this test.

Justification for classification or non-classification

Based on the negative results in the assays assessing genotoxicity in bacteria and in mammalian cells and the negative results for chromosomal aberration test, the substance does not have to be classified for genotoxicity according to EU CLP (EC No. 1272/2008 and its amendments).