(E)-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3-buten-2-one

Endpoint summary

Additional information

Due to the lack of sufficient data regarding genetic toxicity in vitro, data for the analogue substance mixed ionone isomers (CAS No. 8013-90-9) were taken into account as it is a mixture of alpha- and beta-ionone. An Ames test was performed according to OECD guideline 471 and no mutagenic effects were found in bacteria strains S. typhimurium TA 1535, TA 1537, TA 98 and TA 100 when concentrations up to 5000 µg/plate were used. (Givaudan, 2004). Because of the structural similarities it can be assumed, that also for beta-ionone alone no mutagenic effects in vitro have to be expected.

alpha-ionone was tested in an in vitro chromosome aberration assay with CH cell line B241 (Kasamaki et al. 1982). It showed clastogenic effects at the test concentration of 25 mM. This very high concentration does no correspond to the current guideline and understanding of culture conditions. Acc

ording to the current OECD guideline 473, the limit test concentration is 10 mM due to expected unphysiologic conditions at higher concentrations. Since the concentration of a-ionone that increased the frequency of chromosome aberrations was very high and investigators did not provide any data on its cytotoxic effects, these findings must be used with caution. However, the responses do not appear to be translated to in vivo exposures, as a mouse micronucleus assay shows:

The genetic toxicity in vivo was analyzed in a micronucleus test (MNT), which was performed in compliance with OECD Guideline 474 (BASF AG, 2003). Doses of 500 and 750 mg/kg bw given intraperitoneally lead to evident signs of toxicity in the mice (poor general state, irregular respiration, squatting posture) which were reversible after two days. At the low dose (250 mg/kg bw), only minor signs of clincal toxicity were observed after 2 and 4 hours of administration. As a result beta-ionone did not have a chromosome-damaging (clastogenic) effect and there were no indications of any impairment of chromosome distribution in the course of mitosis (aneugenic activity) in bone marrow cells in vivo.

Short description of key information:
Genetic toxicity:
- in vitro: negative, Ames test (OECD 471)
- in vitro: clastogenic, Chrom. Ab.
- in vivo: negative, MNT (OECD 474)

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Due to negative results in studies performed according to OECD Guidelines 471 and 474, no classification for genetic toxicity is required.