(R)-1-hydroxy-1-phenylacetone

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented study report which meets basic scientific principles. The study was not conducted under GLP conditions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

The Ames II Assay is the liquid version of the classical Ames test using microwell plates. The Ames II assay is done in contrast to the classical Ames in microwell plates using a modified fluctuation test protocol. Besides the traditional tester strain TA 98 six his mutant strains TA 7001 - TA 7006 (Ames II tester strains) are used to detect base-pair substitutions.
In both tests mutations are detected by the reversion of mutations present in the amino acid requiring bacterial strains. These reversions result in the recovery of the functional capability to synthesize the essential amino acid. This gain of function leads to grow even in the absence of the amino acid required by the parent strains.
In the Ames II assay this growth leads to an accumulation of catabolites from the metabolic activity of revertants. By the catabolites the pH is dropped down which turns the reversion indicator medium from purple to yellow.
The test was carried out based on the description of Gee et al. (Mut Res 412: 115-130, 1998) and on the "Users Manual" prepared by XENOMETRIX, Inc., Colorado, USA.

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

(R)-1-hydroxy-1-phenylacetone

EC Number:

217-285-4

EC Name:

(R)-1-hydroxy-1-phenylacetone

Cas Number:

1798-60-3

Molecular formula:

C9H10O2

IUPAC Name:

(1R)-1-hydroxy-1-phenylpropan-2-one

Details on test material:

- Name of test material (as cited in study report): (-)-Phenylacetylcarbinol
- Physical state: liquid
- Analytical purity: 65.47 %
- Impurities (identity and concentrations):
(according to analytical report, 2001-03-27)
- test substance: 65.47%
- Benzylalcohol: 27.953 %,
- Phenylmethylglycol 5.946 %
- Benzaldehyd, 1-Phenylpropandion-1,2 (Diketon), 1,2-Dihydroxy-2-methyl-1-phenylbutanon-3 (0.181 %)
- others: 0.453 %
- Lot/batch No.: Pa. 222/26
- Storage condition of test material: room temperature

Method

Target gene:

his operon

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 98

Additional strain / cell type characteristics:

other: rfa-, uvrB-, R-factor

Species / strain 2

Species / strain / cell type:

S. typhimurium, other: TA Mix (Mixed strains TA 7001 - TA 7006)

Additional strain / cell type characteristics:

other: rfa-, uvrB-, R-factor

Metabolic activation:

with and without

Metabolic activation system:

cofactor supplemented post-mitochondrial fraction (S9-mix) prepared from the livers of male Sprague-Dawley rats treated with Aroclor 1254

Test concentrations with justification for top dose:

4, 20, 100, 500, 2500, 5000 µg/mL

Vehicle / solvent:

DMSO was used as solvent because of the limited solubility of test substance in water.

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Remarks:

metabolic activation

Positive control substance:

other: 2-aminoanthracene (2-AA)

Remarks:

for TA 98 and TA Mix; 5 µg/mL (final exposure concentration)

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Remarks:

no metabolic activation

Positive control substance:

other: mix of 2-nitrofluorene and 4-nitroquinoline-N-oxide

Remarks:

for TA 98 and TA Mix; 2-nitrofluorene: 0.25 µg/mL (final exposure concentration), 4-nitroquinoline-N-oxide: 0.0625 µg/mL (final exposure concentration)

Details on test system and experimental conditions:

METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 90 min
- Exposure duration: 48 hrs

NUMBER OF REPLICATIONS: Triplicates

DETERMINATION OF CYTOTOXICITY
- Method:
1.) decreased background lawn (reduced his- background growth) leading from turbid to non-turbid purple wells
2.) decrease in number of positive wells

Evaluation criteria:

A test is to be considered as positive when the following criteria are met:
A dose-related and reproducible increase in the number of positive wells by a factor of 2 (calculated on the basis of baseline data) in at least one tester strain either without or with S9-mix.
A test is to be considered as negative when the number of revertant wells for all tester strains were within the historical negative control range under all experimental conditions.
Each 48-well section of 384-well plates is scored for the number of revertant wells
Three scores were used:
1. An increase in the mean number of positive wells in dose groups compared to the mean values of the actual negative control. In cases of mean spontaneous mutation frequencies < 1 the mean number is corrected to a level reflecting a mean = 1 in order for further calculation of fold increase (based on mean) (1F).
2. An increase in the mean of revertant wells in dose groups calculated on the basis of the baseline data of the actual experiment. The baseline is derived from the mean spontaneous revertant number plus 1 standard deviation from the distribution of spontaneous data (baseline data/(based on mean) + standard deviation) (2F).
3. A separate baseline is derived from within each run against which data generated in that run are compared. A run consists of a number of experiments generally testing different test articles together each using a vehicle control. This leads to an accumulation of replicates for zero-dose controls which are used to calculate the mean spontaneous reversion number for each run (baseline data/ (based on mean) + standard deviation of a run) (3F).

Results and discussion

Test results

Species / strain:

S. typhimurium, other: TA 98, TA Mix (Mixed strains TA 7001 - TA 7006)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

no substance precipitation was found

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Results Liquid fluctuation test

1F: mean number of positive wells in dose groups compared to the mean values of the actual negative control (description given under evaluation criteria)

2F: description given under evaluation criteria

3F: description given under evaluation criteria

TA98 strain, without microsomal activation
Dose	Mean (out of 3)	1F	2F	3F
0	3 ± 0	1	1	0.8
4	1 ± 0.0	0.3	0.3	0.3
20	1.3 ± 0.47	0.4	0.4	0.4
100	1 ± 0.0	0.3	0.3	0.3
500	1.3 ± 1.25	0.4	0.4	0.4
2500	2 ± 1.41	0.7	0.7	0.6
5000	2.7 ± 0.94	0.9	0.9	0.7
4-NCQ + 2-NF	34.3 ± 2.49	11.4	11.4	9.6
TA98 strain, with microsomal activation
Dose	Mean (out of 3)	1F	2F	3F
0	2.7 ± 0.94	1	0.7	0.9
4	3 ± 0.82	1.1	0.8	1
20	0.3 ± 0.47	0.1	0.1	0.1
100	2.3 ± 1.7	0.9	0.6	0.8
500	2.0 ± 1.63	0.8	0.6	0.7
2500	3 ± 0.82	1.1	0.8	1
5000	1.0 ± 0.82	0.4	0.3	0.3
2-AA	42.3 ± 2.05	15.9	11.7	14.4
TA Mix strain, without microsomal activation
Dose	Mean (out of 3)	1F	2F	3F
0	1.3 ± 0.47	1	0.6	0.8
4	1.3 ± 1.89	1	0.6	0.8
20	0.7 ± 0.47	0.5	0.3	0.4
100	0.7 ± 0.47	0.5	0.3	0.4
500	0.7 ± 0.47	0.5	0.3	0.4
2500	0.7 ± 0.47	0.5	0.3	0.4
5000	0.3 ± 0.47	0.3	0.1	0.2
4-NCQ + 2-NF	30.7 ± 0.94	23	13.5	19.2
TA Mix strain, with microsomal activation
Dose	Mean (out of 3)	1F	2F	3F
0	1.3 ± 0.47	1	0.7	0.7
4	1 ± 0.82	0.8	0.6	0.5
20	0.3 ± 0.47	0.3	0.2	0.2
100	0.3 ± 0.47	0.3	0.2	0.2
500	0.7 ± 0.47	0.5	0.4	0.3
2500	0.7 ± 0.47	0.5	0.4	0.3
5000	1.0 ± 0.82	0.8	0.6	0.5
2-AA	30.0 ± 4.97	22.5	16.6	15.6

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative