Rectified Essential Oil of Pogostemon cablin (Lamiaceae) with high content in alpha and delta guaiene obtained from leaves by distillation.

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Ames test: non mutagenic (OECD 471, GLP, K, rel. 1)

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19-28 July 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP study conducted according to OECD 471 Guideline without any deviation.

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

08 April 2015

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: Robertet S.A. / 2523853
- Appearance: Yellow Liquid
- Expiration date of the lot/batch: 10 May 2017

STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Fridge (2-8 °C), protected from air and light

Target gene:

Histidine gene for Salmonella typhimurium

Species / strain / cell type:

S. typhimurium, other: TA 97a, TA 98, TA 100, TA 102 and TA 1535

Details on mammalian cell type (if applicable):

Not applicable

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

0.74 % final concentration in the treatment; S9 fraction produced from the livers of male Sprague-Dawley rats which were treated with 500 mg Aroclor 1254/kg bw intraperitoneally.

Test concentrations with justification for top dose:

First Experiment: 50, 150, 500, 1500 and 5000 μg/plate in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, with and without S9 mix using plate incorporation method
Second Experiment: 156, 313, 625, 1250, 2500 and 500 μg/plate in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, with and without S9 mix using pre-incubation method

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Ethanol
- Justification for choice of solvent/vehicle: In a non-GLP pre-test, the solubility of the test item was tested in a concentration of 50 g/L in dimethyl sulfoxide (DMSO), ethanol and 200 g/L tetrahydrofurane (THF). Ethanol was chosen as vehicle, because the test item was sufficiently soluble in it, and this solvent does not have any effects on the viability of the bacteria or the number of spontaneous revertants in the tested concentrations.
Test substance preparation:
On the day of the start of the first experiment, a stock solution containing 50 g/L of the test item in ethanol was prepared. The test item solution was not sterile filtrated before use. The stock solution was used to prepare the geometric series of the concentrations to be tested. The following nominal concentrations were prepared for the first experiment: 5000 μg/plate, 1500 μg/plate, 500 μg/plate, 150 μg/plate and 50 μg/plate.
On the day of the start of the second experiment, a stock solution containing 50 g/L (nominal) of the test item in ethanol was prepared. The test item solution was not sterile filtrated before use. The stock solution was used to prepare the geometric series of the concentrations to be tested. The following nominal concentrations were prepared for the second experiment: 5000 μg/plate, 2500 μg/plate, 1250 μg/plate, 625 μg/plate, 313 μg/plate and 156 μg/plate.

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

other: 4-Nitro-1,2-phenylene Diamine

Remarks:

without metabolic activation

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

other: 2-Amino-Anthracene

Remarks:

with metabolic activation

Details on test system and experimental conditions:

SOURCE OF TEST SYSTEM: Salmonella typhimurium (all strains used) were obtained from TRINOVA BioChem GmbH (batch of the bacteria strains: TA97a: 4987D, TA98: 5011D, TA100: 4996D, TA102: 4982D, TA1535: 5012D) and were stored as lyophilisates in the fridge at 2-8 °C.

METHOD OF APPLICATION: in agar (plate incorporation); preincubation

DURATION
- Preincubation period: 37 ±1 °C for 20 min
- Exposure duration: 37 ±1 °C for 48 h

NUMBER OF REPLICATIONS:
- Experiment 1 and 2: 3 plates/dose

DETERMINATION OF CYTOTOXICITY
- Method: Evaluation of the toxicity was performed on the basis of growth of the bacterial background lawn.

OTHERS:
- After incubation for 48 h, the revertants were counted and the numbers for each plate were recorded. The colonies were counted visually, the numbers were recorded.

Evaluation criteria:

A substance is considered to have mutagenic potential, if a reproducible increase of revertant colonies per plate exceeding an increase factor of 2 in at least one strain can be observed. A concentration-related increase over the range tested is also taken as a sign of mutagenic activity.

Statistics:

None

Key result

Species / strain:

S. typhimurium, other: TA 97a, TA 98, TA 100, TA 102 and TA 1535

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:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: In all experiments, no precipitation of the test item was observed at any of the tested concentrations up to 5000 μg/plate.

MAIN TEST:
First Experiment:
Solubility and Toxicity: The test item showed no precipitates on the plates in all tested concentrations. No signs of toxicity towards the bacteria strains could be observed. The bacterial background lawn was visible and not affected. The number of revertant colonies was not reduced.
Mutagenicity: No significant increase of the number of revertant colonies in the treatments with and without metabolic activation could be observed. No concentration-related increase over the tested range was found. Therefore, the test item is stated as not mutagenic under the test conditions. To verify this result, a further experiment was performed.

Second Experiment:
Solubility and Toxicity: The test item showed no precipitates on the plates in all tested concentrations. No signs of toxicity towards the bacteria strains could be observed. The bacterial background lawn was visible and not affected. The number of revertant colonies was not reduced.
Mutagenicity: No significant increase of the number of revertant colonies in the treatments with and without metabolic activation could be observed. No concentration-related increase over the tested range was found. Therefore, the test item is stated as not mutagenic under the test conditions.

HISTORICAL CONTROL DATA (with ranges, means and standard deviation)
History of the spontaneous revertants and positive controls of the performed experiments with these strains up to 13 July 2016 is stated in comparison with the experiments performed within this study.
- Positive historical control data:
Without metabolic activation: 389-1152 (616 ± 187); 112-793 (420 ± 154); 223-984 (536 ± 169); 491-2157 (1083 ± 403); 55-484 (244 ± 103) in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, respectively
With metabolic activation: 241-1181 (537 ± 157); 39-217 (78 ± 37); 325-1371 (654 ± 186); 408-6083 (1234 ± 885); 45-284 (108 ± 49) in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, respectively
- Negative (water) historical control data:
Without metabolic activation: 61-144 (99 ± 20); 6-35 (15 ± 6); 62-141 (97 ± 15); 120-389 (266 ± 64); 6-30 (16 ± 6) in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, respectively
With metabolic activation: 63-138 (100 ± 17); 11-41 (18 ± 6); 66-141 (99 ± 15); 125-432 (283 ± 77); 7-30 (16 ± 5) in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, respectively
- Negative (DMSO) historical control data:
Without metabolic activation: 58-135 (99 ± 19); 7-46 (14 ± 6); 60-136 (95 ± 17); 149-381 (265 ± 59); 8-33 (16 ± 6) in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, respectively
With metabolic activation: 70-144 (106 ± 16); 10-36 (17 ± 5); 63-199 (96 ± 22); 129-365 (272 ± 59); 6-29 (16 ± 6) in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, respectively
- Vehicle (Ethanol) historical control data:
Without metabolic activation: 81-181 (106 ± 26); 11-28 (15 ± 5); 61-116 (91 ± 14); 111-368 (283 ± 65); 9-26 (17 ± 6) in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, respectively
With metabolic activation: 87-205 (118 ± 32); 11-26 (16 ± 5); 69-119 (95 ± 16); 141-336 (269 ± 61); 10-24 (17 ± 5) in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, respectively

OTHERS
- Confirmation of genotype was performed for each batch of lyophilized bacteria before stock culture preparation. The last performance showed no abnormalities.
- Confirmation of the Criteria and Validity: All strains met the criterion of at least 10^9 bacteria/mL, and no inconsistencies were found in the sterility control. Nearly all determined values for the spontaneous revertants of the negative controls were in the normal range of the test laboratory. All positive controls (diagnostic mutagens) showed mutagenic effects with and without metabolic activation and nearly all were within the historical control data ranges.

Acceptance criteria:

In all experiments, no precipitation of the test item was observed at any of the tested concentrations up to 5000 μg/plate.

In both experiments, the test item caused no cytotoxicity towards all bacteria strains.

The confirmation tests of the genotype did not show any irregularities. The control of the titre was above the demanded value of 10⁹ bacteria/mL.

Nearly all of the means of all replicates of the spontaneous revertants (in negative and solvent controls) were within the range of the historical data of the test facility. Nearly all numbers of revertant colonies of the positive controls were within the range of the historical data of the, but all were increased in comparison with the negative controls, which demonstrated the mutagenic potential of the diagnostic mutagens.

Since all criteria for acceptability have been met, the study is considered valid.

Conclusions:

Based on the results of this study it is concluded that test item is not mutagenic in the Salmonella typhimurium test strains TA97a, TA98, TA100, TA102 and TA1535 in the absence and presence of metabolic activation under the experimental conditions in the present study.

Executive summary:

In a reverse gene mutation assay performed according to the OECD test guideline No. 471 and in compliance with GLP, strains of Salmonella typhimurium (TA 97a, TA 98, TA 100, TA 102 and TA 1535) were exposed to the test item both in the presence and in the absence of a metabolic activation system. 

First Experiment: 50, 150, 500, 1500 and 5000 μg/plate in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, with and without S9 mix using plate incorporation method

Second Experiment: 156, 313, 625, 1250, 2500 and 500 μg/plate in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, with and without S9 mix using pre-incubation method

 

Negative, vehicle and positive control groups were also included in mutagenicity tests. 

 

The sterility control and the determination of the titre did not show any inconsistencies. The determined values for the spontaneous revertants of the negative controls (vehicle) were in the normal range. All positive controls showed mutagenic effects with and without metabolic activation. Therefore, the sensitivity of the assay and the efficacy of the S9-mix were validated.

 

In all experiments, no precipitation of the test item was observed at any of the tested concentrations up to 5000 μg/plate.

 

In the first experiment, the bacterial background lawn was not reduced at any of the concentrations and no relevant decrease in the number of revertants was observed in all bacteria strains. The test item showed no signs of toxicity towards the bacteria strains in both the absence and presence of metabolic activation. The results of this experiment showed that none of the tested concentrations caused a significant increase in the number of revertants in all tested strains, in the presence and the absence of metabolic activation. To verify this result, a further experiment was performed.

 

In the second experiment, the bacterial background lawn was not reduced at any of the concentrations and no relevant decrease in the number of revertants was observed in all bacteria strains. The test item showed no signs of toxicity towards the bacteria strains in both the absence and presence of metabolic activation. The results of this experiments showed that the test item caused no increase in the number of revertants in all bacteria strains compared to the solvent control, in both the absence and presence of metabolic activation. The test item did not induce a dose-related increase in the number of revertants colonies in all strains, in the presence and absence of metabolic activation.

 

Based on the results of this study it is concluded that test item is not mutagenic in the Salmonella typhimurium strains TA97a, TA98, TA100, TA102 and TA1535 in the absence and presence of metabolic activation under the experimental conditions in this study.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

In a reverse gene mutation assay performed according to the OECD test guideline No. 471 and in compliance with GLP, strains ofSalmonella typhimurium(TA 97a, TA 98, TA 100, TA 102 and TA 1535) were exposed to the test item both in the presence and in the absence of a metabolic activation system. 

First Experiment: 50, 150, 500, 1500 and 5000 μg/plate in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, with and without S9 mix using plate incorporation method

Second Experiment: 156, 313, 625, 1250, 2500 and 500 μg/plate in TA 97a, TA 98, TA 100, TA 102 and TA 1535 strains, with and without S9 mix using pre-incubation method

 

Negative, vehicle and positive control groups were also included in mutagenicity tests. 

 

The sterility control and the determination of the titre did not show any inconsistencies. The determined values for the spontaneous revertants of the negative controls (vehicle) were in the normal range. All positive controls showed mutagenic effects with and without metabolic activation. Therefore, the sensitivity of the assay and the efficacy of the S9-mix were validated.

 

In all experiments, no precipitation of the test item was observed at any of the tested concentrations up to 5000 μg/plate.

 

In the first experiment, the bacterial background lawn was not reduced at any of the concentrations and no relevant decrease in the number of revertants was observed in all bacteria strains. The test item showed no signs of toxicity towards the bacteria strains in both the absence and presence of metabolic activation. The results of this experiment showed that none of the tested concentrations caused a significant increase in the number of revertants in all tested strains, in the presence and the absence of metabolic activation. To verify this result, a further experiment was performed.

 

In the second experiment, the bacterial background lawn was not reduced at any of the concentrations and no relevant decrease in the number of revertants was observed in all bacteria strains. The test item showed no signs of toxicity towards the bacteria strains in both the absence and presence of metabolic activation. The results of this experiments showed that the test item caused no increase in the number of revertants in all bacteria strains compared to the solvent control, in both the absence and presence of metabolic activation. The test item did not induce a dose-related increase in the number of revertants colonies in all strains, in the presence and absence of metabolic activation.

 

Justification for classification or non-classification

Based on the results of this study it is concluded that test item is not mutagenic in theSalmonella typhimuriumstrains TA97a, TA98, TA100, TA102 and TA1535 in the absence and presence of metabolic activation under the experimental conditions in this study.