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Genetic toxicity in vitro

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Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Remarks:
read-across on structural analogue
Adequacy of study:
key study
Study period:
From 2000-03-23 To 2000-10-03
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was performed according to OECD guideline 473 and GLP.
Qualifier:
according to
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.10 (Mutagenicity - In Vitro Mammalian Chromosome Aberration Test)
Deviations:
no
GLP compliance:
yes
Type of assay:
in vitro mammalian chromosome aberration test
Species / strain / cell type:
lymphocytes: primary cells
Details on mammalian cell type (if applicable):
- Type and identity of media: RPMI 1640 containing 20% fetal calf serum, L-glutamine (2mM), penicillin (100 U/ml), streptomycin (100µg/ml) and phytohaemagglutinin.
Metabolic activation:
with and without
Metabolic activation system:
S9 from induced Aroclor 1254 rat liver
Test concentrations with justification for top dose:
- 18.96, 37.93, 75.85, 151.70, 303.41, 606.82, 1213.64 and 2427.27 µg/ml (in the first experiment)
- 75.85, 151.70, 303.41, 606.82, 1213.64 and 2427.27 µg/ml (in the second experiment)
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: ethanol
- Justification for choice of solvent/vehicle: no justification in the study report
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: mitomycin C without S9 mix (3µg/ml for 3 hours of treatment, 0.2 µg/ml for continuous treatment), cyclophosphamide with S9 mix (50 µg/ml)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

DURATION (first experiment)
- Exposure duration: 3h
- Expression time (cells in growth medium): 17h
- Fixation time (start of exposure up to fixation or harvest of cells): 20h

DURATION (second experiment)
- Exposure duration: 3h (without S9); 20h and 44h (with S9)
- Expression time (cells in growth medium): 17h and 41h (without S9); 20h and 44h (with S9)
- Fixation time (start of exposure up to fixation or harvest of cells): 20h and 44h (with and without S9)

STAIN (for cytogenetic assays): Giemsa

NUMBER OF REPLICATIONS: approximately 1.5 normal cell cycles or approximately 1.5 normal cell cycles and 24 hours later.

NUMBER OF CELLS EVALUATED: 100 metaphase/culture

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index

OTHER EXAMINATIONS:
- Determination of polyploidy: yes
- Determination of endoreplication: yes
- Other: gaps, chromatid and chromosome breaks and exchanges, multipleaberrations and pulverization

OTHER: blind scoring
Evaluation criteria:
A reproducible and statistically significant increase in the frequency of cells with structural aberrations for at least one of the dose-levels and one of
the two harvest times was considered as a positive result. Reference to historical data or other considerations of biological relevance, was also taken into account in the evaluation of the findings.
Statistics:
The comparison was performed using the Chi-square test (p = 0.05)
Species / strain:
lymphocytes: primary culture
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
Cytotoxicity:
Without S9:
After 3-hour treatment, a slight decrease in the mitotic index was noted at dose-levels of 1213.64 and 2427.27 µg/ml (up to 34%).
After 20- hour treatment, a 35% decrease in the mitotic index was induced at 2427.27 µg/ml.
After 44-hour treatment, a 33-69% decrease in the mitotic index was noted at dose-levels of 1213.64 and 2427.27 µg/ml.

With S9 mix:
No noteworthy decrease in the mitotic index was noted at the 20 hour harvest time

Chromosal aberration analyses:
The test substance did not induce any significant increase in the frequency of cells with chromosome aberrations in both experiments and at both harvest times, with and without S9 mix.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Conclusions:
Interpretation of results (migrated information):
negative with metabolic activation
negative without metabolic activation

Under the experimental conditions, the test substance Esterol C does not induce chromosome aberrations in cultured human lymphocytes.
Executive summary:

In a GLP mammalian cell cytogenetic assay (chromosome aberration) (Haddouk, 2000), primary lymphocyte cultures were exposed to Esterol C (batch no. 0006503) at concentration of 18.96, 37.93, 75.85, 151.70, 303.41, 606.82, 1213.64 and 2427.27 µg/ml with and without metabolic activation. Positive controls induced the appropriate response. There was no evidence of chromosome aberration induced over background.

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Remarks:
read-across from supporting sustance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
Apriil 2016 - November 2016
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
oecd 476 (2015)
Qualifier:
according to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Version / remarks:
The Organisation for Economic Co-operation and Development (OECD), Guideline for the Testing of Chemicals 476, (adopted by the Council on 28th July 2015), “In vitro Mammalian Cell Gene Mutation Test”.
Deviations:
no
Principles of method if other than guideline:
Principle of the Test Method
Cells deficient in Hypoxanthine-guanine Phosphoribosyl Transferase (HPRT), due to mutation, are resistant to the cytotoxic effects of the purine analogue (6-thioguanine). HPRT proficient cells are sensitive to 6-thioguanine which causes the inhibition of cellular metabolism and halts further cell division. HPRT deficient cells are presumed to arise through mutation at the hprt locus; they cannot metabolize 6-thioguanine and thus survive and grow in its presence.
GLP compliance:
yes
Type of assay:
mammalian cell gene mutation assay
Specific details on test material used for the study:
Fatty acids, C6-24 and C6-24-unsatd., Me esters, distn. residues- Physical state: black , brown semisolid- Analytical purity:100% - Storage condition of test material: room temperature- Solubility: < 10% in water, soluble in acetone, hexane and dichloromethane

Batch/Lot Number 01-37
Date of Manufacture September 2015
Storage Temperature : Room temperature
Storage Container : In original container as supplied by the Sponsor
Storage Location : Test Item Control Office (TICO), JRF

Target gene:
CHO-K1 cell line (free from mycoplasma contamination), a subclone of the Chinese hamster ovary cell line obtained from the Japanese Collection of Research Bioresources (JCRB), maintained in the Mutagenicity Section at Jai Research Foundation was used for this study. The cells were grown as monolayer in disposable tissue culture flasks and were free from any contamination during the conduct of the study.
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Details on mammalian cell type (if applicable):
CHO - K1
Metabolic activation:
with and without
Metabolic activation system:
A metabolically active extract of rat liver (treated with Aroclor 1254) called S9 fraction was used.
The S9 fraction procured Molecular Toxicology, Inc. (Lot No 3570) was used in this assay. The S9 fraction is buffered and supplemented with the essential co-factors -NADP, KCl and Glucose-6-phosphate to form the “S9 mix”. The S9 fraction was used at a concentration of 2% in the final culture medium for the Main Study.

Preparation of S9 Mix:
For treatment in the presence of metabolic activation, S9 fraction was used at a final concentration 2% v/v (Main Study).
Constituent of Co-factor Mix and S9 Mix
a. D-Glucose-6-phosphate : 180 mg/mL
b. -Nicotinamide adenine dinucleotide phosphate (-NADP) : 25 mg/mL
c. Potassium chloride : 11.18 mg/mL
Ratio of the individual constituents in Co-factor Mix (1:1:1).
The medium for treatment in presence of metabolic activation was prepared by the addition of required volume of co-factor mix to the required volume of medium maintained on ice.
α-MEM with nucleosides devoid of serum was used for testing in the absence of metabolic activation system (Main Study).

Test concentrations with justification for top dose:
Treatment was performed both in the absence and presence of metabolic activation (2% v/v S9). Cultures were maintained in duplicate for each test concentration, negative and positive controls.
Cultures were exposed at concentrations of 78.125, 156.25, 312.5, 625 and 1250 µg/mL in the absence and 39.0625, 78.125, 156.25, 312.5 and 625 µg/mL in the presence of metabolic activation (2% v/v S9 mix) for a period of 4 hours. For the treatment, the first stock solution (stock A) of the test item was prepared by dissolving 500 mg (500.14 mg rounded to 500 mg) of Fatty acids, C6-24 and C6-24 unsatd., Me esters, distillation Residues in DMSO and volume was made up to 4 mL (125000 µg/mL).
Vehicle / solvent:
The test item was insoluble in sterile distilled water, while formed emulsion in DMSO at 500000 µg/mL. Therefore, DMSO was selected as the vehicle for this study.
No significant change in pH (± 1 unit) or osmolality (≥ 50 mOsm/kg H2O) was observed at 0 and 3 h at any tested concentration (156.25, 312.5, 625, 1250, 2500 and 5000 µg/mL of culture medium). Turbidity was observed at the tested concentrations of 2500 and 5000 µg/mL , while slight turbidity was observed at the tested concentrations of 625 and 1250 µg/mL. Precipitation was not observed up to 312.5 µg/mL of culture medium. The results of pH, osmolality and precipitation tests are provided in APPENDIX 5 of the study report.
Therefore, the guideline limit concentration of 5000 µg/mL was selected as the highest concentration for the cytotoxicity test
Untreated negative controls:
yes
Remarks:
DMSO
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
ethylmethanesulphonate
Details on test system and experimental conditions:
Controls:
Concurrent negative (DMSO) and positive controls were maintained in duplicate, both in the absence and presence of a metabolic activation system. Ethyl Methanesulfonate (0.4 µL/mL) was used as the positive control in the absence of metabolic activation and Benzo(a)pyrene (6 µg/mL) was used as the positive control in the presence of metabolic activation.

Culture Medium:
α-MEM (Minimum Essential Medium, Eagle α-Modification with nucleosides) with nucleosides (Gupta R.S., 1984) with 10% heat inactivated, sterile, fetal bovine serum was used as the culture medium to grow the CHO-K1 cell line. Culture medium was also supplemented with Penicillin (50 IU/mL of medium) and Streptomycin (50 µg/mL). At the time of selection Minimum Essential Medium Eagle -modification without nucleosides (-MEM w/o NS) with 10% dialyzed fetal bovine serum was used.
The medium to eliminate existing mutants in the culture for treatment was prepared by addition of 2 mL of reconstituted HAT (Hypoxanthine Aminopterine Thymidine) supplement to 98 mL of α-MEM w/o NS with 5% fetal bovine serum [50X vial of HAT media supplement was reconstituted using 10 mL of sterile α-MEM w/o NS. The reconstituted supplement contains 5 x 10-3 Hypoxanthine, 2 x 10-5 M Aminopterine and 8 x 10-4 M Thymidine].

Selective Agent:
2-amino-6-mercaptopurine (6-thioguanine) was used as selective agent at a concentration of
5 µg/mL -MEM without nucleosides.

Culture Vessels:
Disposable tissue cultures flasks of 75 cm2 culture (Corning) area with canted neck were used to culture the cell line. Treatment was given in the same flask. 60 mm disposable culture dishes (Corning) were used to determine the cloning efficiency. Tissue culture dishes (Corning) of 100 mm were used to select mutant colonies.
Rationale for test conditions:
Solubility Test
Solubility was tested at 500000 µg/mL in order achieve the guideline limit dose of 5000 µg/mL. The test item was found to be insoluble in sterile distilled water, however it formed emulsion in dimethyl sulfoxide at 500000, 250000 and 125000 µg/mL. The test item was further diluted with dimethyl sulfoxide to lower concentrations to check for precipitation and changes in pH and osmolality.

Precipitation and pH Test
Prior to the cytotoxicity test, precipitation, pH and osmolality checks were performed to select the maximum achievable concentration in culture medium. The stock solution of 500000 µg/mL was serially diluted to obtain stock solutions of 250000, 125000, 62500, 31250 and 15625 µg/mL. A volume of 50 µL of relevant stock solutions was added to 4.950 mL of culture medium to obtain the final concentration of 5000, 2500, 1250, 625, 312.5 and 156.25 µg/mL of culture medium. The pH, precipitation and osmolality of test concentrations in culture medium were assessed at approximately 0 and 3 h after incubation at 37 ± 1 °C and 5% CO2 in a CO2 incubator.

Cytotoxicity Test:
Based on the results of solubility, precipitation, osmolality and pH tests, 5000 µg/mL was selected as the highest concentration to be tested for the cytotoxicity test. The cytotoxicity test was performed both in the absence and presence of metabolic activation (2% v/v S9 mix) at concentrations of 625, 1250, 2500 and 5000 µg/mL. A concurrent negative (DMSO) control was also maintained.
Based on the cytotoxicity test results a concentration of 1250 and 625 µg Fatty acids, C6-24 and C6-24 unsatd., Me esters, distillation Residues/mL were selected as the highest concentration for the main study experiment both in the absence and presence of metabolic activation system (2% v/v S9 mix), respectively.
Evaluation criteria:
Assay Acceptance Criteria
A mutation assay was considered acceptable if it met the following criteria:
a. The criteria for acceptability was a minimum 60% absolute cloning efficiency in negative controls (DMSO) and a spontaneous mutant frequency less than 20 per 106 clonable cells (Nestmann, E.R. et al,. 1991).
b. Positive controls induce a significant increase in the mutant frequency above the concurrent negative control.
2.22.2 Assay Evaluation Criteria
A test item was considered positive in the mutation assay if:
i. Test item causes a concentration-related biologically significant increase in mutant frequency in comparison with concurrent negative control and the test item causes a three-fold increase (Nestmann, E.R. et al., 1991) in the number of 6-thioguanine resistant colonies relative to concurrent negative control and such increases were statistically significant and outside the laboratory historical negative (DMSO) control range.
ii. A net increase in mutant colonies of treated above the concurrent control was observed in at least two of the concentrations tested.
Clear negative results obtained in trial-I were not confirmed by a repeat test (short duration), as per revised OECD guideline.
Statistics:
Statistical Analysis
Weighted regression analysis was performed to evaluate the dose response relationship (Li, A.P. et al., 1987; Hsie, A.W. et al., 1981) on fatty Acids, C6-24 And C6-24 unsatd., Me Esters, Distillation Residues treatment groups against the negative control group (excluding positive control).
Key result
Species / strain:
Chinese hamster Ovary (CHO)
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:
RESULTS
Solubility, Precipitation, pH and Osmolality Tests
The test item was insoluble in sterile distilled water, while formed emulsion in DMSO at 500000 µg/mL. Therefore, DMSO was selected as the vehicle for this study.
No significant change in pH (± 1 unit) or osmolality (≥ 50 mOsm/kg H2O) was observed at 0 and 3 h at any tested concentration (156.25, 312.5, 625, 1250, 2500 and 5000 µg/mL of culture medium). Turbidity was observed at the tested concentrations of 2500 and 5000 µg/mL , while slight turbidity was observed at the tested concentrations of 625 and 1250 µg/mL. Precipitation was not observed up to 312.5 µg/mL of culture medium. The results of pH, osmolality and precipitation tests are provided in APPENDIX 5.
Therefore, the guideline limit concentration of 5000 µg/mL was selected as the highest concentration for the cytotoxicity test.

Cytotoxicity Test
Test item cytotoxicity was assessed by calculating the percent relative cloning efficiency following treatment.
The pH and osmolality at the beginning of treatment at 5000 µg/mL was 7.19 and 496 mOsm/kg H2O, respectively (compared to 7.18 and 474 mOsm/kg H2O in the negative control) in the absence of metabolic activation, while pH and osmolality at 5000 µg/mL was 7.11 and 491 mOsm/kg H2O, respectively (compared to 7.20 and 483 mOsm/kg H2O in the negative control), in the presence of metabolic activation (APPENDIX 6). Hence, no significant change in the pH or osmolality was observed up to the guideline limit concentration of 5000 µg/mL both in the absence and presence of metabolic activation.
The percent relative cloning efficiency observed was 39.61, 18.13 in the absence of metabolic activation and 15.25 in the presence of metabolic activation (2% v/v S9), at tested concentrations of 625, 1250 µg/mL in the absence of metabolic activation and 625 µg/mL in the presence of metabolic activation of culture medium, respectively. Excessive toxicity i.e., > 90% cells observed, were dead at the tested concentrations of 2500, 5000 and 1250, 2500 and 5000 in the absence and presence of metabolic activation of culture medium, respectively.
Based on the observed results and to achieve guidelines required cytotoxicity limit i.e. 10-20% relative survival, 1250 µg/mL was selected as the highest concentration in the absence and 625 µg/mL was selected as the highest concentration in the presence of metabolic activation for the main study experiment.

Mutagenicity Test:
No biologically relevant influence of the test item on osmolality and pH was observed in the absence and presence of metabolic activation during the main study.


Adjusted Absolute and Relative Cloning Efficiency/Survival Following Treatment

The mean adjusted absolute cloning efficiency (ACE) and percent relative cloning efficiency/survival following treatment both in the absence and presence of metabolic activation in the Main Study are summarised below:

Group

(µg/mL)

Main Study

- S9

+ S9 (2% v/v S9 mix)

-

Mean Adjusted ACE

RCE(%)

Mean Adjusted ACE

RCE(%)

NC (DMSO)

3.49

100.00

3.32

100.00

T1 (78.125)

T1 (39.0625)

3.16

90.54

3.05

91.87

T2 (156.25)

T2

(78.125)

2.95

84.53

2.92

87.95

T3 (312.5)

T3

(156.25)

2.77

79.37

2.64

79.52

T4

 (625)

T4

(312.5)

1.35

38.68

1.39

41.87

T5 (1250)

T5

(625)

0.69

19.77

0.56

16.87

PC

2.66

76.22

2.48

74.7

The individual data is provided inAPPENDIX1. The dose response curves for relative cloning efficiency in the presence and absence of metabolic activation are providedFIGUR

Absolute Cloning Efficiency at Selection and Mutant Frequency

The mean absolute cloning efficiency (ACE) at selection and mean mutation frequency per 1 x 106cells (MF) in the absence and presence of metabolic activation for the Main Study are provided below:

Group

(µg/mL)

Main Study

- S9

+ S9 (2% v/v S9 mix)

Mean ACE

Mean MF

Mean ACE

Mean
MF

NC (DMSO)

0.7012

16.10

0.6897

16.94

T1 (78.125)

T1 (39.0625)

0.6840

15.89

0.6637

15.76

T2 (156.25)

T2

(78.125)

0.6786

15.80

0.6559

17.18

T3 (312.5)

T3

(156.25)

0.6917

15.38

0.6679

17.23

T4

 (625)

T4

(312.5)

0.6625

16.40

0.6732

16.44

T5 (1250)

T5

(625)

0.6352

17.12

0.6650

16.97

PC

0.6416

325.18

0.6530

368.80


The values of absolute cloning efficiency at selection, number of mutant colonies and mutant frequency for each test concentration are provided inTABLE2with individual data inAPPENDIX2andAPPENDIX3. The dose response curves for mutant frequency bothin the absence and presence of metabolic activation for the Main Study are provided inFIGURE2.

A weighted regression analysis was performed to evaluate any significant dose-related effect in mutation frequency of cultures treated with fatty acids, C6-24 and C6-24 unsatd., Me esters, distillation Residues with the concurrent negative control group. Statistical analysis was not performed for the positive controls.Themean mutant frequencyof the positive control exhibited a clear increase over the mean value of the negative control demonstrating that positive controlhad potential to induce gene mutations at thehprtlocus of CHO-K1 both in the absence and presence of metabolic activation.This also demonstrated that the S9 mix was capable of metabolizing a pro-mutagen to its mutagenic form(s), thus, demonstrating integrity of the S9 mix.

The regression equation for Main Study is given below:

Main Study

Regression Equation

Absence of metabolic activation

Presence of metabolic activation

Y = 0.001 X + 15.699

Y = 0.0004 X + 16.653

The absolute cloning efficiency in the negative control was above 60% during main study. The mutant frequency in the negative control group was less than 20 per 106clonable cells during the main study validating the acceptability of the test system (Li, A.P.et al., 1987). A significant dose-related increase in the mutation frequency was not observed in any of the treated concentrations and the mutation frequency was comparable to that from the negative control group. The increased mutant frequency observed in the positive controls in main study demonstrated the efficiency of the test system and suitability of the test procedures and conditions employed in the study.

Conclusions:
Based on the results of cytotoxicity test, proposed concentrations for Mutagenicity experiment are:           
78.125, 156.25, 312.5, 625, 1250 in the absence of metabolic activation
39.0625, 39.0625, 78.125, 156.25, 312.5 and 625 µg/mL in the presence of metabolic activation of culture medium.

According to the main study experiment of in vitro cell gene mutation test, the substance is found to be non mutagenic up to the tested concentration of 1250 µg/ml in the absence and 625 µg/ml in the presence of metabolic activation system.
From these results, it is concluded that Fatty acids, C6-24 and C6-24 unsatd., Me esters, Distillation Residues does not have potential to induce gene mutations at the hprt locus of CHO-K1 cells, both in the absence and presence of metabolic activation under the experimental conditions described.

Executive summary:

In a mammalian cell gene mutation assay [hprtlocus], CHO-K1 cells culturedin vitrowere exposed toFatty Acids, C6-24 And C6-24 unsatd., Me Esters, Distillation Residuesat different concentrations, both in the absence and presence of metabolic activation (2% v/v S9 mix) for a period of 4 hours.

Cultures were exposed toFatty Acids, C6-24 And C6-24 unsatd., Me Esters, Distillation Residuesat 5 concentrations (two cultures/dose-level) between 78.125 and 1250 µg/mL of culture medium, in the absence of metabolic activation and between 39.0625 and 625 µg/mL in the presence of metabolic activation (2% v/v S9 mix), selected from a preliminary cytotoxicity test for a period of 4 hours.

No significant dose-related increase in mutation frequency was observed in any treatment concentration between 78.125 and 1250 µg/mL of culture medium in the absence and 39.0625 and 625 µg/mL of culture medium in presence of metabolic activation system (2% v/v S9 mix). The induced mutation frequency was comparable to that of the negative control group. All negative controls were within the historical limits and positive controls showed a clear increase in mutant frequency. No biologically relevant influence of the test item on pH or osmolality was observed both in the absence and presence of metabolic activation during the main study.

All criteria for a valid study were met as described in the study plan. Based on the results from this study, it is concluded thatFatty Acids, C6-24 And C6-24 unsatd., Me Esters, Distillation Residuesdoes not have potential to induce gene mutations at thehprtlocus of CHO-K1 cells both in the absence and presence of metabolic activation system under the experimental conditions described.

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Remarks:
read across on similar subastance or structural analogue
Adequacy of study:
key study
Study period:
From 1999-03-08 To 1999-04-22
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: 1a: The study was performed according to OECD 406 guideline and GLP.
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay
Species / strain / cell type:
S. typhimurium, other: TA 1535, TA 1537, TA 98, TA 100 and TA 102
Metabolic activation:
with and without
Metabolic activation system:
S9 from induced Aroclor 1254 Rat liver
Test concentrations with justification for top dose:
0, 62.5, 125, 250, 500 and 1000 µg/plate, for all tested strains in the first experiment.
0, 312.5, 625, 1250, 2500 and 5000 µg/plate, for all tested strains in the second experiment.
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: ethanol
- Justification for choice of solvent/vehicle: The solvent was chosen because of its solubility properties.
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: sodium azide (-S9, TA 1535 and TA 100) (1 µg/plate); 9-aminoacridine (-S9, TA 1537) (50 µg/plate); 2-nitrofluorene (-S9, TA 98) (0.5 µg/plate); Mitomycin C (-S9, TA 102) (0.5 µg/plate); 2-Anthramine (+S9, all strains) (10 µg/plate for TA102, 2 µg/plate f
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation) and preincubation only for the second experiment with S9 mix.
DURATION
- Preincubation period: 60 minutes
- Exposure duration: 48 to 72 hours

DETERMINATION OF CYTOTOXICITY
- Method: other: The evaluation of the toxicity was performed on the basis of the observation of the decrease in the number of revertant colonies and/or a thinning of the bacterial lawn during a preliminary toxicity test.
Evaluation criteria:
A reproducible two-fold increase in the number of revertants compared with the vehicle controls, in any strain at any dose-level and/or evidence of a dose-relationship was considered as a positive result.
Statistics:
No statistical analysis was used.
Species / strain:
S. typhimurium, other: TA 1535, TA 1537, TA 98, TA 100 and TA 102
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
COMPARISON WITH HISTORICAL CONTROL DATA: The number of revertants of the vehicle and positive controls was consistent with historical
data.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- Experiments without S9 mix:
Except for a slight thinning of the bacterial lawn noted in the TA strain at 1000 µg/plate, no toxicity was noted in the first experiment. In the second
experiment, a slight to marked toxicity was noted in the TA 1537 and TA 100 strains at dose-levels >= 625 µg/plate. In the TA1535 and TA 98
strains, a slight to moderate toxicity was mainly noted at dose-levels>=1250 µg/plate.
- Experiments with S9 mix:
No toxicity was noted in the first experiment in all tester strains. In the second experiment (preincubation method) a slight to moderate toxicity was induced in the TA 1535, TA 1537 and TA 100 strains mainly at dose-levels >= 1250 µg/plate.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Table 1: Number of revertants per plate (first experiment) (mean of 3 plates)

TA 1535 TA 1537 TA 98 TA 100 TA 102
Conc. [unit] - MA +MA - MA + MA - MA + MA - MA + MA - MA + MA
0 9 14 7 10 17 28 79 90 154 188
62.5 9 14 8 8 12 28 79 92 175 238
125 12 13 9 8 13 27 79 100 174 228
250 11 15 5 9 19 29 75 107 176 235
500 10 14 7 9 17 24 81 91 174 202
1000 10 11 7 8 15 26 72 93 162 241
Positive control 471 332 314 110 160 937 564 1904 932 1735

MA: metabolic activation

Table 2: Number of revertants per plate (second experiment) (mean of 3 plates)

TA 1535 TA 1537 TA 98 TA 100 TA 102
Conc. [unit] - MA +MA - MA + MA - MA + MA - MA + MA - MA + MA
0 17 18 9 12 26 34 99 115 168 190
62.5 14 19 9 7 17 31 111 89 196 142
125 11 15 5 7 22 31 86 91 211 199
250 11 15 8 5 15 27 80 77 159 191
500 11 10 6 5 17 34 67 81 158 177
1000 7 10 2 3 15 32 58 65 129 146
Positive control 385 242 385 112 161 1031 405 1106 823 1646

MA: metabolic activation

Conclusions:
Interpretation of results (migrated information):
negative with metabolic activation
negative without metabolic activation

Esterol C does not show any mutagenic activity in the bacterial reverse mutation test on Salmonella typhimurium strains.
Executive summary:

In a reverse gene mutation assay in bacteria (Haddouk, 1999) strains of Salmonella typhimurium (TA 1535, TA 1537, TA 98, TA 100 and TA 102) were exposed to Esterol C (batch 99.06.501) at concentration of, 0, 62.5, 125, 250, 500 and 1000 µg/plate in the presence and absence of mammalian metabolic activation. The positive controls induced the appropriate responses in the corresponding strains. No noteworthy increase in the number of revertants was induced in all tested strains with and without metabolic activation.

This study is classified as acceptable. This study satisfies the requirement for Test Guideline OECD 471 for in vitro mutagenicity (bacterial reverse gene mutation) data.

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

Genetic toxicity in vivo

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

Additional information

In a reverse gene mutation assay in bacteria (Haddouk, 1999) strains of Salmonella typhimurium (TA 1535, TA 1537, TA 98, TA 100 and TA 102) were exposed to Esterol C (batch 99.06.501) at concentration of, 0, 62.5, 125, 250, 500 and 1000 µg/plate in the presence and absence of mammalian metabolic activation. The positive controls induced the appropriate responses in the corresponding strains. No noteworthy increase in the number of revertants was induced in all tested strains with and without metabolic activation.

In a supporting in vitro assessment of the mutagenic potential of Rapeseed Methyl Ester, histidinedependent auxotrophic mutants of Salmonella typhimurium, strains TA1535, TA1537, TA98 and TA100, and a tryptophan-dependent mutant of Escherichia coli, strain WP2 uvrA (pKM101), were exposed to Rapeseed Methyl Ester diluted in dimethyl sulphoxide (DMSO). DMSO was also used as a negative control. Two independent mutation tests were performed in the presence and absence of liver preparations (S9 mix) from rats treated with phenobarbital and 5,6-benzoflavone. The first test was a standard plate incorporation assay; the second included a pre-incubation stage. Concentrations of Rapeseed Methyl Ester up to 5000 μg/plate were tested. No signs of toxicity were observed towards the tester strains in either mutation test. No evidence of mutagenic activity was seen at any concentration of Rapeseed Methyl Ester in either mutation test. 

In a GLP mammalian cell cytogenetic assay (chromosome aberration) (Haddouk, 2000), primary lymphocyte cultures were exposed to Esterol C (batch no. 0006503) at concentration of 18.96, 37.93, 75.85, 151.70, 303.41, 606.82, 1213.64 and 2427.27 µg/ml with and without metabolic activation. Positive controls induced the appropriate response. There was no evidence of chromosome aberration induced over background.

A slight comitogenic activity has been reported in mouse linphoma cells for methyl miristate, but the result is doubt for other tested chainlenghts (Baxter 1981)

To test for possible anticlastogenic effects of fatty acids (Renner, 1986) , the methyl esters of fatty acids — short-chain to long-chain — were examined on busulfan in Chinese hamster bone-marrow cells using the chromosome aberration test. When the experimental animals were treated with fatty acid esters and the mutagen, the chromosome-breaking actions of busulfan were not modulated by the short-chain fatty acids, but the fatty acids from lauric acid (C12) up to nonadecanoic acid (C19) reduced the rate of aberrant metaphases from 9.4 to about 3% at doses of 100 mg/kg and less. Other chemical properties of the fatty acids (saturated or not, number of double bonds, even- or odd-numbered) had no influence on the anticlastogenic effects.

All performed studies on genetic toxicity both in vitro and in vivo, on bacterial and mammalian cells on the substance and on a numer of different members of the category showed negative results. No further test are proposed

Short description of key information:

The substance is not mutagenic

Justification for classification or non-classification

All study results are negative.

No classification for mutagenicity is warranted under 67/548/EEC or Regulation 1272/2008.