2-Propyn-1-ol, compd. with 2-methyloxirane (1:?)

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

In vitro

Ames Test

The Ames Test was carried out in accordance with the OECD guideline for testing of chemicals "Genetic Toxicology: Salmonella typhimurium, Reverse Mutation Assay", No. 471 and in accordance with the EEC Directive 92/69, B 14: Mutagenicity (Salmonella typhimurium - reverse mutation assay). The test was performed as Standard Plate Test and Preincubation Test with and without a metabolic activation using the indicator organisms TA 1535, TA 1537, TA 98 and TA 100. Parallel with each experiment a negative control (vehicle control, sterility control) was carried out for each tester strain in order to determine the spontaneous mutation rate. Furthermore positive control substances were used to check the mutability of the bacteria and the activity of the S-9 mix: 2 -aminoanthracene (with S-9 mix, for the strains TA 100, TA 98, TA 1537 and TA 1535), N-methyl-N'-nitro-N-nitrosoguanidine ( without S-9 mix, for the strains TA 100 and TA 1535), 4 -nitro-o-phenylendiamine (without S-9 mix, for the strain TA 98), 9 -aminoacridine chloride monohydrate (without S-9 mix, for the strain TA 1537). Each experiment was performed with 3 test plates per dose or control while the concentrations of the test item were 20, 100, 500, 2500, and 5000 µg/plate. Neither the preincubation test nor the standard plate test with or without metabolic activation increased the number of his+ revertants in any of the tested bacteria strains.

HPRT-Test

The study was performed to investigate the potential of 2-Propyn-1-ol, compd. with methyloxirane to induce gene mutations at the HPRT locus in V79 cells of the Chinese hamster. The study was performed according to OECD 476 guideline and GLP (BASF SE, 2012).

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 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 applied in the pre-experiment was 7690 μg/mL according to OECD guideline, considering the purity of the test item (preliminary information concerning the purity at the start of the experiment: 65 - 69% main component; 31 - 35% water). The concentration range of the main experiments was limited by cytotoxic effects. The test item was dissolved in deionised water.

No substantial and reproducible dose dependent increase of the mutation frequency was observed up to the maximum concentration with and without metabolic activation.

Appropriate reference mutagens (EMS and DMBA), used as positive controls, induced a distinct increase in mutant colonies and thus, showed the sensitivity of the test system and the activity of the metabolic activation system.

In 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, 2-Propyn-1-ol, compd. with methyloxirane is considered to be non-mutagenic in this HPRT assay.

Chromosome Aberration test

The test item 2-Propyn-1-ol, compd. with methyloxirane, dissolved in deionised water, was assessed for its potential to induce structural chromosome aberrations in V79 cells of the Chinese hamster in vitro in two independent experiments according to OECD 473 guideline and GLP (BASF SE, 2012).

ln each experimental group two parallel cultures were set up. At least 100 metaphases per culture were evaluated for structural chromosome aberrations, except for the positive control in Experiment IB without metabolic activation, where only 50 metaphases were evaluated.

The highest applied concentration (7690.0 ug/ml) was chosen with regard to the composition of the test item and with respect to the current OECD Guideline 473 (preliminary information concerning the purity at the start of the experiment: 65 - 69%> main component; 31 - 35% water).

Dose selection for the cytogenetic experiments was performed considering the toxicity data.

ln Experiment lA in the absence and presence of S9 mix clear cytotoxicity was observed at the highest evaluated concentration. ln Experiment IB only moderate cytotoxicity was observed in the absence and presence of S9 mix.

Statistically significant increases of aberrant cells were observed in Experiment lA in the absence of S9 mix after treatment with 3845.0 ug/ml (4.8 % aberrant cells, excluding gaps) and in the presence of S9 mix after treatment with 961.3 ug/ml (5.3 % aberrant cells, excluding gaps). Both values exceeded the range of the historical solvent control data (0.0 - 4.0 °/o aberrant cells, excluding gaps). ln Experiment IB clastogenicity clearly exceeding the historical solvent control data (0.0- 4.0 % aberrant cells, excluding gaps) was observed at nearly all evaluated concentrations with (8.5 - 14.5 % aberrant cells, excluding gaps) and without (7.0 - 16.0 % aberrant cells, excluding gaps) metabolic activation. However, the

value at 721.0 ug/ml in the presence of S9 mix (5.0 % aberrant cells, excluding gaps) is slightly exceeding the historical solvent control data but is not statistically significant. The percentage of aberrant cells, excluding gaps after treatment with 3364.4 ug/ml in the absence of S9 mix is statistically significant (3.0 %) due to the low response in the solvent control (0.5 % aberrant cells, excluding gaps). Additionally, the number of cells, carrying exchanges was markedly increased in both experimental parts.

No relevant increase in polyploid and endomitotic metaphases was found after treatment with the test item as compared to the frequencies of the control cultures.

Appropriate mutagens (EMS and CPA) were used as positive controls. They induced statistically significant increases in cells with structural chromosome aberrations.

ln conclusion, it can be stated that under the experimental conditions reported, the test item induced structural chromosome aberrations in V79 cells (Chinese hamster cellline) in vitro.

Therefore, 2-Propyn-1-ol, compd. with methyloxirane is considered to be clastogenic in this chromosome aberration test in the absence and presence of metabolic activation, when tested up to cytotoxic or the highest required concentrations.

In vivo

Mikronucleus-Assay

This study was performed to investigate the potential of 2-Propyn-1-ol, compd. with methyloxirane to induce micronuclei in polychromatic erythrocytes (PCE) in the bone marrow of the mouse according to OECD 474 guideline and GLP (Harlan CCR, 2013).

The test item was dissolved in sterile water, which was also 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 item the bone marrow cells were collected for micronuclei analysis.

At least five males per test group were evaluated for the occurrence of micronuclei. Per animal 2000 polychromatic erythrocytes (PCEs) were scored for micronuclei.

To investigate a cytotoxic effect due to the treatment with the test item the ratio between polychromatic and normochromatic erythrocytes was determined in the same sample and reported as the number of PCEs per 2000 erythrocytes.

Based on results of pre-experiments, doses of 250, 500 and 1000 mg/kg b.w. for male mice administered once orally were selected for the main experiment. However, due to high mortality observed at 1000 mg/kg (4 of 7 males of the 48 hours group) this dose was not appropriate for evaluation in accordance with the guidelines (less than 5 animals available for evaluation in the 48 hour group and maximum tolerated dose level clearly exceeded). Additional groups of male mice were treated including vehicle and positive control in a second main experiment in order to fulfil the OECD guideline requirements for a valid study. Finally, following dose levels of the test item were investigated and evaluated :

24 h preparation interval: 125^b), 250^a), and 500^a)mg/kg b.w.
48 h preparation interval: 500^b)mg/kg b.w.

                  ^a)First main experiment^b)Second main experiment

In the second main experiment one of 7 males died after treatment with the high dose (500 mg/kg b.w., 48 hours post-treatment).

After treatment with the test item the number of PCEs was not substantially decreased as compared to the mean value of PCEs of the vehicle control thus indicating that 2-Propyn-1-ol, compd. with methyloxirane did not exert a cytotoxic effect in the bone marrow.

In comparison to the corresponding vehicle controls there was no biologically relevant or statistically significant enhancement in the frequency of the detected micronuclei at any preparation interval after administration of the test item and with any dose level used. Only the micronucleus frequency found in the high dose group (48 hours treatment) was statistically significantly higher (0.108%) compared to the concurrent vehicle control value, which was incidentally quite low (0.030%). However, the micronucleus frequency in the 500 mg/kg (48h) group as well as in all other test item treated dose groups at any preparation interval were very well within the laboratory’s historical vehicle control data (0.010-0.250%, mean 0.108%). Thus, the observed statistical significance at 500 mg/kg (48h) was not considered to have any biological relevance.

40 mg/kg b.w. cyclophosphamide administered orally was used as positive control which showed a substantial increase of induced micronucleus frequency.

In conclusion, it can be stated that under the experimental conditions reported, the test item 2-Propyn-1-ol, compd. with methyloxirane did not induce micronuclei as determined by the micronucleus test with bone marrow cells of the mouse.

Therefore, 2-Propyn-1-ol, compd. with methyloxirane is considered to be non-mutagenic in this micronucleus assay.

Short description of key information:
in vitro:
Ames-Test (BASF AG, 1995): negative
HPRT-Test (BASF SE, 2012): negative
In vivo:
Mikronucleus-Assay (Harlan CCR, 2013): negative

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Negative results were obtained with an Ames-Test and with a HPRT-Test. The positive in vitro results in a chromosome aberration test could not be confirmed in an in vivo Micronucleus Assay. Threfore no classification for mutagenicity is required according to EU directive 67/548/EEC and EU classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.