4-phenoxyphenol

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

On the basis of the OECD guideline 471 and read-across data (OECD 473 and 476), the 4 -phenoxyphenol does not induce genetic toxicity.

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

Due to the toxicity of the test item a supplementary dose was studied.

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Batch n°20180328
- Expiration date of the lot/batch: March 2019

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature
- Stability under test conditions: stable under the storage condition

Target gene:

his-operon (S. typhimurium)
trp-operon (E. coli)

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Details on mammalian cell type (if applicable):

Strains of Salmonella typhimurium are purchased from MOLTOXTM.

Species / strain / cell type:

E. coli WP2 uvr A pKM 101

Details on mammalian cell type (if applicable):

Strains of Salmonella typhimurium are purchased from MOLTOXTM.

Metabolic activation:

with and without

Metabolic activation system:

S9-mix. S9 fraction, microsome fraction prepared from Sprague Dawley rat liver homogenate, is provided by MOLTOXTM

Test concentrations with justification for top dose:

500, 250, 150, 50 , 15 and 5 μg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: no
- Vehicle controls tested: medium with DMSO alone

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

7,12-dimethylbenzanthracene

9-aminoacridine

2-nitrofluorene

sodium azide

other: cis-Platinum (II) Diammine Dichloride and 2-Anthramine

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Preincubation period: 48-72 hour incubation period at 37° C

NUMBER OF REPLICATIONS:
- 3 culture plates per strain per dose or per control were prepared.
- If the first assay is positive, the second one is performed in the same manner.
- If the first assay, in presence of test item, is negative, the pre-incubation test is performed for the second assay.repli

NUMBER OF CELLS EVALUATED: Not applicable, as the number of revertant colonies per plate was calculated.

DETERMINATION OF CYTOTOXICITY
- Method: cloning efficiency; relative total growth

Evaluation criteria:

Ensure that the criteria of validity of the study are well respected namely :
- the bacteriostatic activity of the highest concentration tested shall be equal to or less than 75 %,
- the spontaneous reversion rate of the absolute negative control shall comply with the historical values of the laboratory,
- the spontaneous reversion rate of the solvent shall not be statistically different from absolute negative control,
- the mean number of revertant colonies obtained for each strain and the corresponding positive control, with and/or without metabolic activation shall comply with the historical values of the laboratory.
- Negative and positive values should not show significant difference with the historical values of the laboratory (± 2 standard deviations).

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

E. coli WP2 uvr A pKM 101

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Conclusions:

Doses (500, 250, 150, 50, 15 and 5 μg/plate) prepared from solutions of the test item Para-phenoxyphenol do not induce any mutagenic change in Salmonella typhimurium TA 1535, TA 1537, TA 98, TA 100 and in Escherichia coli WP2(uvrA¯) (pKM 101) without, or with metabolic activation, according to the OECD Guidelines 471.

Executive summary:

A test in accordance of OECD guideline n°471 was performed to test the capacity of 4 -phenoxyphenol to induce reverse mutation in four Salmonella typhimurium strains and one Escherichia coli WP2(uvr A¯)(pKM101) strain. This study was performed in the absence and presence of metabolic activation. Two independent assays were carried out

For assay n° 1, various concentrations were put in contact with the strains in the absence and presence of a metabolic activation system (S9-mix 10% (v/v)).

For assay n° 2, various concentrations were put in contact with the strains in the absence of metabolic activation and with pre-incubation in the presence of metabolic activation system (S9-mix 10% (v/v)).

For the two assays, negative and positive controls were carried out in parallel. Positive controls induced a significant increase in the number of revertant colonies compared to negative controls. There is no significant difference between the number of spontaneous reversions, the number of reversions obtained in the positive controls (without and with metabolic activation), and the mean of corresponding experimental “historical” values obtained in the laboratory (Table 11).

These results validate the two tests.

There is no evidence of any increase in the number of revertant colonies in the presence of the various concentration of the test item (500, 250, 150, 50 , 15 and 5 μg/plate), without and with metabolic activation in Salmonella typhimurium TA 1535, TA 1537, TA 98, TA 100 and in Escherichia coli WP2(uvrA¯) (pKM 101).

Reference 2

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

See 2018_Read-across-Justification_V1 in attached justification

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across: supporting information

Key result

Species / strain:

Chinese hamster Ovary (CHO)

Remarks:

The results of this assay indicate that doses of 500 to 5000 ug/ml without S-9 and 250 to 5000 ug/ml with S-9 were cytotoxic and resulted in no cell survival.

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Diphenyl Oxide was evaluated for cytotoxicity utilizing cell proliferation kinetics as a parameter at doses of 5, 50, 100, 250, 500, 750., 1000, 2500 and 5000 ug/ml with and without S-9.
At the time of treatment, there was a cloudy white precipitate in the media and crystal formation at 1000 to 5000 ug/ml, increasing in amount with increasing doses. The results of this assay indicate that doses of 500 to 5000 ug/ml without S-9 and 250 to 5000 ug/ml with S-9 were cytotoxic and resulted in no cell survival.

Conclusions:

As indicated in the read-across justification, data from Diphenyl Ether can be used for read-across to 4-Phenoxy Phenol systemic toxicological endpoints.
Therefore as Diphenyl Oxide, produced no statistically significant increase in the number of aberrations/cell and the proportion of aberrant metaphases at any dose level evaluated with and without S-9 mix.4 -PhenoxyPhenol has a negative result chromosom aberration study in mammalian cells.

Executive summary:

As indicated in the read-across justification, data from Diphenyl Ether can be used for read-across to 4-Phenoxy Phenol systemic toxicological endpoints.

Therefore as Diphenyl Oxide, produced no statistically significant increase in the number of aberrations/cell and the proportion of aberrant metaphases at any dose level evaluated with and without S-9 mix.4 -PhenoxyPhenol has a negative result in chromosom aberration study in mammalian cells.

Reference 3

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

See 2018_Read-across-Justification_V1 in attached justification

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across: supporting information

Key result

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The assay produced relative cell survivals of 23.5, 27.0, 17.3, 0.6 and 0.2% at the 333 ug/ml dose level at respective S-9 concentrations of 0, 1, 2, 5 and 10%.

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Test article, Diphenyl Oxide, was evaluated in the CHO/HGPRT Mammalian Cell Forward Gene Mutation Assay at dose levels of 10, 50, 100, 167 and 333 ug/ml of treatment volume without and with a 1% (v/v) concentration of metabolic activation (S-9) preparation. There were no statistically significant increases in the mutation frequencies of Diphenyl Oxide treated cultures when compared to the negative controls. The lack of any statistically significant increases sheds doubt upon the previously reported increase in the Preliminary Mutagenicity Assay. In as much as only one dose point did produce any type of response, and the response was not reproducible, those results are throught to be spurious in nature

Conclusions:

As indicated in the read-across justification, data from Diphenyl Ether can be used for read-across to 4-Phenoxy Phenol systemic toxicological endpoints.
Therefore as there were no statistically significant increases in the mutation frequencies of Diphenyl Oxide treated cultures when compared to the negative controls. 4 -PhenoxyPhenol has a negative result in in vitro gene mutation study in mammalian cells.

Executive summary:

As indicated in the read-across justification, data from Diphenyl Ether can be used for read-across to 4-Phenoxy Phenol systemic toxicological endpoints.

Therefore as there were no statistically significant increases in the mutation frequencies of Diphenyl Oxide treated cultures when compared to the negative controls. 4 -PhenoxyPhenol has a negative result in in vitro gene mutation study in mammalian cells.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)