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Key value for chemical safety assessment

Additional information

The genotoxic potential of the substance was investigated in an in vitro bacterial reverse mutation assay (Ames test) conducted using methodology similar/equivalent to OECD guideline 471 (Safepharm Laboratories Limited, 1988).

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100 and E. coli WP2 uvr A- were exposed to the test material in DMSO at concentrations of 12.5. 25, 50, 100, and 200 µg/plate using the plate incorporation method both with and without S9.

Under the conditions of this study, no significant increase in the numbers of revertant colonies was recorded for any of the bacterial strains with any dose of p-cumyl phenol, either with or without metabolic activation. p-Cumyl phenol was determined to be non-mutagenic.

 

The genotoxic potential of the substance was investigated in an in vitro mammalian chromosome aberration test conducted per OECD Test Guideline 473 under GLP conditions (BioReliance, 2001).

Chinese hamster Ovary (CHO) cells were exposed to p-cumyl phenol at concentrations of 3.75 to 60 µg/mL in DMSO both with and without S9.

p-Cumylphenol was positive for the induction of structural aberrations in CHO cells in a non-metabolically activated system. However, p-Cumylphenol was concluded to be negative in the induction of structural aberrations in a metabolically activated system and did not induce numerical aberrations in either system.

 

The genotoxic potential of the substance was investigated in an in vitro mammalian cell gene mutation test conducted per OECD Test Guideline 476 under GLP conditions (BioReliance, 2001).

Mouse lymphoma L5178Y cells were exposed to test material concentrations in DMSO up to 50.0 µg/mL without metabolic activation (5.0 – 50 µg/mL) and concentrations up to 60.0 µg/mL with metabolic activation (5.0 – 60 µg/mL).

p-Cumylphenol was non mutagenic with and without S9 metabolic activation.


Justification for selection of genetic toxicity endpoint
No single study is selected as key on the basis that the different studies address different aspects of genetic toxicity and the data are therefore all considered to be key.

Short description of key information:
p-Cumyl phenol did not induce gene mutations either with or without metabolic activation in Bacterial or Mammalian cell systems in-vitro. The substance was noted as positive for the induction of structural aberrations only in CHO cells without metabolic activation. p-Cumyl phenol was negative for the induction of structural aberrations with metabolic activation and did not induce numerical aberrations either with or without activation.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

No classification is proposed for p-cumyl phenol as the genotoxicity data is equivocal. Bacterial and mammalian cell mutation assays both indicate the substance is non-mutagenic while a single in-vitro Chromosome Aberation study was noted as positive for structural aberrations without metabolic activation only.