Reaction mass of 4-isopropylidene-1-methylcyclohexene and 1-isopropyl-4-methyl-7-oxabicyclo[2.2.1]heptane and 1,3,3-trimethyl-2-oxabicyclo[2.2.2]octane

Endpoint summary

Additional information

Terpinolene multiconstituent was tested in a reverse gene mutation assay in bacteria, performed according to OECD guideline 471 and in compliance with GLP, in S. typhimurium strains (TA 1535, TA 1537, TA 98, TA 100 and TA 102), either with or without metabolic activation, up to a limiting plate incorporation level of 5000 micrograms/plate or up to cytotoxic concentrations. The results were negative.

Terpinolene multiconstituent was also tested, in presence and in absence of metabolic activation, in a chromosome aberration test performed in cultured human lymphocytes according to OECD guideline 473 and in compliance with GLP. The substance did not increase the rate of chromosomal aberrations except under the test condition 20h exposure without S9. This result was judged equivocal and terpinolene multiconstituent was reinvestigated in an in vitro micronucleus test under the same experimental conditions (20h exposure without S9) in the same test system (cultured human lymphocytes). The result was clearly negative.

The results of a gene mutation test (HPRT) in CHO cells were also negative. Terpinolene multiconstituent was tested with and without metabolic activation. The study was performed according to OECD guideline 476 and in compliance with GLP.

There is no requirement to conduct additional genotoxicity tests with terpinolene multiconstituent, as negative results were obtained in appropriate test systems.

Justification for selection of genetic toxicity endpoint
Several in vitro studies were used to complete this endpoint: Ames, HPRT, chromosome aberration and micronucleus tests.

Short description of key information:
Negative results were obtained with terpinolene multiconstituent in two in vitro mutagenicity studies (Ames test and HPRT test). The results of a chromosome aberration test were also negative except for the test condition 20h exposure without S9. However, the toxicological significance of this observation was considered questionable and the substance was reinvestigated immediately in an in vitro micronucleus test performed under the same experimental conditions (20h exposure without S9) and with the same test system (cultured human lymphocytes). The result was then clearly negative.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

The results of the in vitro tests performed with terpinolene multiconstituent (mutagenicity in bacteria, mutagenicity in mammalian cells and clastogenicity in mammalian cells) were negative. Based on these studies, terpinolene multiconstituent is not expected to induce heritable mutations in germ cells and is therefore not classified for mutagenicity/genotoxicity according to Directive 67/548/EEC and CLP Regulation (EC) No 1272 /2008.