2-ethyl-4-hydroxy-5-methylfuran-3(2H)-one

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vitro

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 442D (In Vitro Skin Sensitisation: ARE-Nrf2 Luciferase Test Method)

GLP compliance:

yes (incl. QA statement)

Type of study:

activation of keratinocytes

Test material

Test material information

1

Reference substance name:

2-ethyl-4-hydroxy-5-methylfuran-3(2H)-one

EC Number:

248-514-6

EC Name:

2-ethyl-4-hydroxy-5-methylfuran-3(2H)-one

Cas Number:

27538-10-9

Molecular formula:

C7H10O3

IUPAC Name:

2-ethyl-4-hydroxy-5-methylfuran-3(2H)-one

In vitro test system

Details on the study design:

This in vitro study was performed to assess the potential of the test item Furanone Homo to activate the Nrf2 transcription factor by using the genetically modified keratinocyte cell-line “LuSens” (Bauch et al. 2012).
It employs the use of a reporter gene for luciferase placed under the control of the antioxi-dant response element (ARE) and hence monitors Nrf2 transcription factor activity. The measured endpoint is the up-regulation of luciferase activity after 48 h of incubation with the test substance at different concentrations. This up-regulation is an indicator for the activation of the Keap1/Nrf2/ARE signalling pathway (Ade et al. 2009, Natsch 2012, Natsch & Emter 2008, Vandebriel et al. 2010). In order to conclude on the Nrf2 transcription factor activity of the test substance, at least two, but a maximum of three independent and valid experiments are performed.

Results and discussion

Positive control results:

EGDMA (120 µM) was used as positive control. The viability was above 70 % and a dis-tinct increase in luciferase induction above 2.5 fold in comparison to the solvent control was detected. This luciferase induction is well within the historical data range of the posi-tive control.

In vitro / in chemico

Results

Results 1

Key result

Run / experiment:

other: Experiment I

Parameter:

other: Relative Viability(%)

Value:

80

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Key result

Run / experiment:

other: experiment II

Parameter:

other: Relative Viability(%)

Value:

80

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

This in vitro study was performed to investigate the potential of Furanone Homo to activate the Nrf2 transcription factor (sensitizing potential), by using the LuSens cell line.

A detailed listing of all measured and calculated values of the assay is given in Annex 2 (values of CRFT), Annex 3 (values of experiment I), and Annex 4 (values of experiment II). In addition, the final results of both experiments are summarized in table 8-a and 8-b and graphically illustrated in figure 8-a to 8-d.

The assay was performed in two independent experiments. 12 concentrations of the test item were evaluated. The exposure time was 48 h. The following nominal concentrations of the test item were investigated in experiment I and II:
269 µM, 323 µM, 388 µM, 465 µM, 558 µM, 670 µM, 804 µM, 965 µM, 1157 µM, 1389 µM, 1667 µM, 2000 µM
None of the real treatment concentrations in both experiments deviated more than 10 % from the nominal concentration. Precipitation of the test item was not visible up to the highest concentration.

EGDMA (120 µM) was used as positive control. The viability was above 70 % and a dis-tinct increase in luciferase induction above 2.5 fold in comparison to the solvent control was detected. This luciferase induction is well within the historical data range of the posi-tive control.
DL-lactic acid (5000 µM) was used as negative control. The viability was above 70 % and the induction of the luciferase was < 1.5 fold in comparison to the solvent control and well within the historical data range of the negative control (table 18-a).
The induction of the luciferase of the growth control (Medium no. 3) was < 1.5 fold.
Since all acceptability criteria of the assay were met the study is valid.

No cytotoxic effect was observed in all tested test item concentrations. Therefore, all tested concentrations could be evaluated for luciferase induction.
Finally the following test item concentration showed a viability ≥ 70 % and could therefore be evaluated for luciferase induction (experiment I and II):
269 µM, 323 µM, 388 µM, 465 µM, 558 µM, 670 µM, 804 µM, 965 µM, 1157 µM, 1389 µM, 1667 µM, 2000 µM
A statistically significant (see Annex 8) increase ≥ 1.5 fold in luciferase induction was measured in the following concentrations in experiment I: 965 µM, 1157 µM, 1389 µM, 1667 µM, 2000 µM
A statistically significant (see Annex 8) increase ≥ 1.5 fold in luciferase induction was measured in the following concentrations in experiment II: 1389 µM, 1667 µM, 2000 µM
Therefore, both experiments are clearly positive.

In conclusion, it can be stated that under the experimental conditions of this study, the test item, Furanone Homo, was positive in the LuSens assay and is therefore considered having the potential to activate the Nrf2 transcription factor (sensitizing potential).