4-allylveratrole

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in chemico

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 Oct 2017-28 Feb 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 442C (In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA))

GLP compliance:

yes (incl. QA statement)

Type of study:

direct peptide reactivity assay (DPRA)

Justification for non-LLNA method:

The correlation of protein rectivity with skin sensitisation potential is well established. Haptenation i.e. covalent binding of low molecluar weight substances (Haptens) to proteins present in skin is considered a prominent mechanism through which chemicals or their metabolites become antigenic. Therefore, information inferred from the DRPA assay is relevant for assessment for skin sensitisation potential of substances.

Test material

Test material information

Constituent 1

Reference substance name:

4-allylveratrole

EC Number:

202-223-0

EC Name:

4-allylveratrole

Cas Number:

93-15-2

Molecular formula:

C11H14O2

IUPAC Name:

1,2-dimethoxy-4-(prop-2-en-1-yl)benzene

Test material form:

liquid

In chemico test system

Details on the study design:

Solutions of test item and positive control prepared at 100 mM concentration were used in the sample preparation for analysis. Test solution, positive control and reference control was added to cysteine and lysine peptides and incubated in dark at 25°C for 24±2 hours. The test samples were then loaded in HPLC auto sampler to measure the peptide depletion. The test samples were then analysed by reversed-phase HPLC coupled with UV detector for detection of peptides at 220nm. The HPLC column Zorbax SBC18 (2.1mm X100mm X 3.5 micron) was equilibrated at 30°C with 50% phase A (0.1% (v/v) trifluoroacetic acid in water) and 50% phase B (0.085% (v/v) trifluoroacetic acid in acetonitrile). Analysis was carried out at a flow rate of 0.35 mL/min, with sample injection volume range of 10 μL. A linear gradient from 10% to 25% Acetonitrile over 10 minutes, was used for separation, followed by a rapid increase to 90% acetonitrile to remove other materials. Cysteine and lysine peptide Percent Depletion Values were then calculated from peptide peak areas obtained from the HPLC analysis.

Results and discussion

Positive control results:

Cinnamaldehyde showed 71.03% mean cysteine depletion and 35.59% mean lysine peptide depletion.

In vitro / in chemico

Results

Results 1

Key result

Parameter:

other: % of cysteine peptide depletion

Value:

4.9

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Key result

Parameter:

other: % of lysine peptide depletion

Value:

1.09

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

Table 1. Reactivity class classification of test item and positive control as per cysteine 1:10 lysine 1:50 prediction model.

Sample ID	Name of the chemical	Mean % of cysteine peptide depletion	Mean % of lysine peptide depletion	Mean peptide % peptide depletion	Reactivity class	DPRA prediction
Y02 -01	4 -allylveratrole, Methyl Eugenol	4,90	1,09	3,00	No or minimal acticity	Negative
CA	Cinnamic aldehyde	71,03	35,59	53,31	High reactivity	Positive

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The mean percent depletion was 4.90% for cysteine peptide and 1.09% for lysine peptide. The mean of cysteine and lysine peptide depletion was 3.00% which shows that the test item has no or minimal activity according to cysteine 1:10/lysine 1:50 prediction model. Hence it was concluded that the test item 4-allyveratrole, Methyl Eugenol is negative in skin sensitisation test by DPRA.

Executive summary:

Skin sensitisation by in chemico test method, Direct Peptide Reactivity Assay (DPRA) was carried out using the nucleophile containing synthetic cysteine and lysine peptides to evaluate skin sensitisation potential of the test item 4 -allylveratrole (Methyl Eugenol). The mean percent depletion was 4.90% for cysteine peptide and 1.09% for lysine peptide. The mean of cysteine and lysine peptide depletion was 3.00% which shows that the test item has no or minimal activity according to cysteine 1:10/lysine 1:50 prediction model. Under the same conditions positive control cinnamaldehyde showed 71.03% and 35.59% mean cysteine and lysine peptide depletion confirming the sensitivity of the assay. Under the test conditions, test item, 4 -allylveratrole, Methyl Eugenol was concluded as negative in the skin sensitisation assay by direct peptide reactivity assay (DPRA).