Reaction mass of cis-1-methyl-1-(4-methylcyclohexyl) ethyl acetate and trans-1-methyl-1-(4-methylcyclohexyl) ethyl acetate and cis- 4-isopropyl-1-methylcyclohexyl acetate and trans-4-isopropyl-1-methylcyclohexyl acetate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

In a local lymph node assay performed according to OECD Guideline 429 and in compliance with GLP, stimulation index for 5, 10, 25, 50 and 100 % were 1.33, 1.19, 1.74, 3.58 and 6.13, respectively. The calculated effective concentration inducing an SI of 3 (EC3) was 42 %.

Migrated from Short description of key information:
In a LLNA, Menthanyl acetate multiconstituent induced skin sensitisation with an EC3=42%.

Justification for selection of skin sensitisation endpoint:
Only study available for this endpoint

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

In a local lymph node assay performed according to OECD Guideline 429 and in compliance with GLP, groups of CBA/J mice (4 females/dose) were exposed to 25 µL of Menthanyl acetate multiconstituent in Acetone/Olive oil (4/1, v/v) at concentrations of 0 (vehicle control), 5, 10, 25, 50 and 100 % (v/v) to the dorsal surface of both ears for three consecutive days. On Day 6, all animals were injected with 3H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised and measured for radioactivity expressed as number of disintegrations per minute (DPM) and stimulation index. The test concentrations for the main study were determined from a preliminary study where dryness of skin was noted on day 6 in the right ear of females 315 and 316 treated at 100%. No notable increase in ear thickness was observed at any tested concentrations. The highest concentration retained for the main test was therefore 100%.

No clinical signs and no mortality were observed during the main test. Dryness of ear skin was observed on day 6 in all females at the concentration of 100%, associated with erythema in 3/4 females. Stimulation index for 5, 10, 25, 50 and 100 % were 1.33, 1.19, 1.74, 3.58 and 6.13, respectively. The calculated effective concentration inducing an SI of 3 (EC3) was 42 %. Positive control (α-hexylcinnamaldehyde) exhibited evidence of sensitisation (SI = 7.90).

A significant lymphoproliferation (SI > 3) was noted at the concentration 25% and above. In the absence of local irritation, the significant lymphoproliferative responses observed were attributed to delayed contact hypersensitivity.

Justification for classification or non-classification

Menthanyl acetate multiconstituent induced positive response in LLNA with an EC3=42% therefore it is classified "R43: May cause sensitisation by skin contact" according to the Annex VI of the Directive 67/548/EEC and skin sensitiser Category 1B according to the Regulation (EC) N° 1272-2008 (CLP).