Registration Dossier

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Ames test (OECD 471): negative in S. typhimurium TA92, TA1535, TA100, TA 1537, TA94 and TA98 with metabolic activation

A read-across approach was additionally conducted on source substance isobutyl 4-hydroxybenzoate:

Ames (OECD 471): not mutagenic in S. typhimurium TA 98, TA 100, TA 1535, TA 1537 and E. coli WP2 uvr A with and without metabolic activation

Link to relevant study records

Referenceopen allclose all

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Justification for type of information:
refer to analogue justification provided in IUCLID section 13
Reason / purpose:
read-across source
Key result
Species / strain:
S. typhimurium, other: TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Remarks on result:
other: Source: CAS 4247-02-3, Verbaan, 2016, Ames
Conclusions:
The result of the available in vitro gene mutation study in bacteria performed with source substance isobutyl 4-hydroxybenzoate was negative. Therefore, as explained in the analogue justification, the target substance butyl 4-hydroxybenzoate is not expected to show mutagenic properties.
Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
missing 5th strain (S. typhimurium TA102 or E.coli WP2), exposure only in the presensce of S9-mix; no information on positive control; only duplicate plates tested
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
21 Jul 1997
Deviations:
yes
Remarks:
missing 5th strain (S. typhimurium TA102 or E.coli WP2), exposure only in the presensce of S9-mix; no information on positive and negative controls; only duplicate plates tested
Principles of method if other than guideline:
Method was carried out according to the method of Ames, McCann & Yamasaki (1975).
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay
Target gene:
his operon
Species / strain / cell type:
S. typhimurium, other: TA92, TA1535, TA100, TA1537, TA94 and TA98
Metabolic activation:
with
Metabolic activation system:
cofactor supplemented post-mitochondrial fraction (S9 mix), prepared from the livers of rats treated with polychlorinated biphenyls (500 mg/kg body weight of Kanechlor KC-400 in olive oil, ip)
Test concentrations with justification for top dose:
6 different concentrations; maximum dose: 1 mg/plate
The maximum dose represents the highest non-cytotoxic dose used in the experiment.
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
not specified
Details on test system and experimental conditions:
METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 20 min
- Exposure duration: 2 days

NUMBER OF REPLICATIONS: duplicates
Evaluation criteria:
The result was considered positive if the number of colonies found was twice the number in the control (exposed to the appropriate solvent or untreated). If no reasonable dose response was detected, additional experiments using different doses or induced mutation frequency
assays were performed.
Key result
Species / strain:
S. typhimurium, other: TA92, TA1535, TA100, TA1537, TA94 and TA98
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not specified
Untreated negative controls validity:
not examined
Positive controls validity:
not specified
Conclusions:
Under the conditions of the conducted test the substance was not mutagenic in any of the six strains (TA92, TA1535, TA100, TA1537, TA94 and TA98) tested with metabolic activation up to 1mg/plate.
Executive summary:

A bacterial gene mutation assay with butyl 4 -hydroxybenzoate was performed to a protocol similar to OECD Guideline 471 (Ishidate, 1984). In this study the substance was not mutagenic in any of the six S. typhimurium strains (TA92, TA1535, TA100, TA 1537, TA94 and TA98) tested with metabolic activation up to 1 mg/plate.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Read-across justification

There is one limited study on the bacterial mutagenicity of target substance butyl 4 -hydroxybenzoate available. The assessment of bacterial mutagenicity was additionally based on a study conducted with source substance isobutyl 4 -hydroxybenzoate as part of a read across approach, which is in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5. For each specific endpoint the source substance structurally closest to the target substance is chosen for read-across, with due regard to the requirements of adequacy and reliability of the available data. Structural similarities and similarities in properties and/or activities of the source and target substance are the basis of read-across. A detailed justification for the analogue read-across approach is provided in the technical dossier (see IUCLID Section 13).

 

In vitro

CAS 94 -26 -8

A bacterial gene mutation assay with the target substance butyl 4 -hydroxybenzoate was performed to a protocol similar to OECD Guideline 471 (Ishidate, 1984). In this study the substance was not mutagenic in any of the six S. typhimurium strains (TA92, TA1535, TA100, TA 1537, TA94 and TA98) tested with metabolic activation up to 1 mg/plate.

 

CAS 4247-02-3

Mutagenic activity of isobutyl 4-hydroxyparaben was investigated in a bacterial reverse mutation assay (Ames test; test strains used: S. typhimurium TA 98, TA 100, TA 1535, TA 1537 and E. coli WP2 uvr A according to OECD 471 (Verbaan, 2016).Test concentrations up to 1,600 µg/plate were tested in the experiment. The test compound proved to be not mutagenic to the bacterial strains.

 

Conclusion:

Based on the available data (weight of evidence) and following the analogue approach, butyl 4-hydroxybenzoate is not expected to be mutagenic in bacteria.

 

Overall concusion for genetic toxicity:

In the literature further data on genotoxicity are available on butyl 4-hydroxybenzoate. Butyl 4-hydroxybenzoate was shown to cause sister-chromatid exchange (SCE), structural chromosome aberration (CA), and DNA migration in the comet assay in Chinese hamster cells in vitro at 0.75 mM (equivalent to 0.146 mg/mL) (Tayama et al., 2007). In contrast, three publications show negative results for chromosomal aberration in Chinese hamster cells (Ishidate et al., 1984; Ishidate at al., 1978; Yoshida et al., 1978). Further, in an in vivo comet assay according to OECD 489 the test substance did not induce DNA damage in any observed organ at the limit dose of 2000 mg/kg bw (Sasaki et al., 2002).

Overall, the majority of available genotoxicity tests for butyl 4-hydroxybenzoate in mammalian cells in vitro and in vivo show negative results. Thus, butyl 4-hydroxybenzoate is not considered to be mutagenic or clastogenic.

 

Ishidate, M. et al. (1978) Cytotoxicity test on medical drugs. Chromosome aberration tests with Chinese hamster cells in vitro.Eisei Shikensho Hokoku 96:55--61.

Ishidate, M. et al. (1984) Primary mutagenicity screening of food additives currently used in Japan. Food Chem Toxicol 22:623--636.

Sasaki, Y. F. et al. (2002) The comet assay with 8 mouse organs: results with 39 currently used food additives. Mutation Research 519 (2002):103–119

Tayama S. et al. (2007) Genotoxic effects of environmental estrogen-like compounds in CHO-K1 cells.Mutation Research 649 (2008):114–125

Yoshida, S. et al. (1978) Cytogenetic studies of antimicrobials on cultured cells. Tokyo Toritsu Eisei Kenkyusho Kenkyo Nempo (Annu. Rep. Tokyo Metrop. Res. Lab. Public Health) 29(2): 86-88 1978

Justification for classification or non-classification

Therefore, based on the read-across approach and on data available for the target substance itself, the available data on genetic toxicity do not meet the classification criteria according to Regulation (EC) 1272/2008.