Veratraldehyde

Endpoint summary

Description of key information

Skin sensitisation (read across from Piperonal, which was tested in an OECD TG 429): sensitising

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vitro

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Reference 2

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

3-10 September 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

other: CBA/J

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Jackson Laboratories, Bar Harbor, ME 04609
- Age at study initiation: 9 weeks
- Specification: purpose-bred and experimentally naive at the outset of the study
- Weight at study initiation: 18 - 24 g (on initial dose day)
- Housing: Group housed 5 per cage
- Diet: Free access to Harlan Teklad Certified Rodent Chow 7012C
- Water: Free access to tap water
- Acclimation period: 7 days.

ENVIRONMENTAL CONDITIONS (target ranges)
- Temperature (°C): 22 - 25.6
- Humidity (%): 21 - 48
- Photoperiod (hrs dark / hrs light): 12/12

Vehicle:

other: EtOH/DEP

Concentration:

The test item at concentrations of 1, 2.5, 5, 10 and 25% w/v in the vehicle.

No. of animals per dose:

5

Details on study design:

A range finding test was not conducted for this study. The doses were selected so that the highest concentration maximizes exposure while avoiding systemic toxicity and excessive local irritation. Doses were selected based on known reported uses of the material.

TREATMENT PROCEDURES:
TOPICAL APPLICATION:
On Days 1, 2 and 3, each test animal in its group received an open application of 25 ul of an appropriate dilution of test item in vehicle to the dorsum of both ears. The positive control group (5 females) was treated with hexylicinnamaldehyde. All test and control animals were given a two-day rest period on Days 4 and 5.

ADMINISTRATION OF 3H-METHYL THYMIDINE:
On Day 6 of the study, all test and control animals were injected i.v. with 20 uCi of 3H-Thymidine in sterile saline. Five hours after injection, animals were sacrificed and the draining auricular lymph nodes excised.

DETERMINATION OF INCORPORATED 3HTdR:
The lymph nodes from each group were pooled and a single cell suspension was prepared. Cells were washed twice with PBS and precipitated with 5% trichloroacetic acid overnight at 2-8°C. The pellets were resuspended in 1 mL of TCA and transferred to a vial containing scintillation fluid. Incorporation of tritiated thymidine was measured by liquid scintillation counter.

OBSERVATIONS:
Individual body weights were recorded on Day 1 prior to dosing and Day 6 prior to injection. All test and control animals were observed daily for mortality and any excessive irritation at the test site. Clinical observations ere performed daily on day 4-6.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

DPM for each group was determined. Increases in 3H-thymidine incorporation relative to the vehicle-treated control was derived for each group.

Positive control results:

The positive control item, hexyl cinnamic aldehyde, at 5%, 15% and 35% gave a Stimulation Index of 5.5, 6.1 and 19.5, respectively.

Key result

Parameter:

EC3

Remarks:

%

Value:

25

Parameter:

SI

Remarks on result:

other: The SI values calculated for the substance concentrations 1, 2.5, 5, 10 and 25% were 1.1, 1.9, 2.2, 2.1 and 3.0, respectively.

Results:

Animal group	Test item concentration	Average DPM count	SI (test / control ratio)	Results
Vehicle control	-	965.8		-
Test group I	1%	1069.7	1.1	-
Test group II	2.5%	1843.3	1.9	-
Test group III	5%	2160.2	2.2	-
Test group IV	10%	2001.4	2.1	-
Test group V	25%	2910.7	3.0	+
Positive control I	5%	5273.2	5.5	+
Positive control II	15%	5936.3	6.1	+
Positive control III	35%	18853.7	19.5	+

VIABILITY / MORTALITY:

There was no mortality throughout the study.

CLINICAL SIGNS:

All animals appeared normal for the duration of the study. No erythema or edema was seen in any of the animals during the study. On day 3, three out of 5 mice from the vehicle control group and 2 out of 5 mice from the 25% test material treatment group had ears that appeared wet. Furthermore, on days 2 -5, mice in the positive control groups had ears that appeared wet.

BODY WEIGHTS:

There were no statistically significant differences observed between any of the treatment groups.

Interpretation of results:

other: Skin sensitising (category 1B)

Remarks:

According to Regulation (EC) No. 1272/2008 and its amendments.

Conclusions:

The SI values calculated for the substance concentrations 1, 2.5, 5, 10 and 25% were 1.1, 1.9, 2.2, 2.1 and 3.0, respectively. These results show that the test substance could elicit a SI ≥ 3. An EC3 has been derived resulted in an EC3 of 25%. The test substance was considered to be a sensitiser under the conditions of the test.

Executive summary:

The skin sensitisation potential of the substance has been tested according to OECD TG 429 and GLP principles. At 1, 2.5, 5, 10 and 25% the substance showed SI values of 1.1, 1.9, 2.2, 2.1 and 3.0, respectively. Reliable negative and positive controls were included. All animals appeared normal for the duration of the study.

These results show that the test substance could elicit a SI ≥ 3. An EC3 has been derived of 25%.

Based on the results, the substance is considered to be a skin sensitiser.

Reference 3

Endpoint:

skin sensitisation, other

Remarks:

Read-across

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The information is derived from read across

Justification for type of information:

The full read-across document can be found in the Endpoint Summary and also the accompanying files.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

EC3

Remarks:

%

Value:

25

Interpretation of results:

other: Skin sensitising (category 1B)

Remarks:

According to Regulation (EC) No. 1272/2008 and its amendments.

Conclusions:

Based on the data available it can be concluded that the substance is a skin sensitiser.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

The skin sensitization is based on read across from Piperonal. First the study with the analogue is described and thereafter the read across justification is presented.

Veratraldehyde was tested in HRIPT at the concentration of 10% causing positive reactions in 1/11 patients.

LLNA test:

The skin sensitisation potential of the substance has been tested according to OECD TG 429 and GLP principles. At 1, 2.5, 5, 10 and 25% the substance showed SI values of 1.1, 1.9, 2.2, 2.1 and 3.0, respectively. Reliable negative and positive controls were included. All animals appeared normal for the duration of the study. These results show that the test substance could elicit a SI ≥ 3. An EC3 has been derived of 25%, therefore the substance is considered to be a skin sensitiser.

Veratraldehyde and its sensitising potential using read across from Piperonal (CAS 120-57-0)

 

Introduction and hypothesis for the read across

Veratraldehyde is a phenol structure with two short ether-alkyl chains attached in the meta and para positions of the phenol ring, both chains have one carbon. For Veratraldehyde no relevant data on skin sensitization are available, which are not sufficient to make a decision for this endpoint. Therefore, additional information is used in accordance with Article 13 of REACH where it is said that lacking information should be generated whenever possible by means other than vertebrate animal tests, i.e. applying alternative methods such as in vitro tests, SARs, grouping and read-across.

Hypothesis: Veratraldehyde is expected to have the same sensitising potency as Piperonal.

Available experimental information: For the target substance, Veratraldehyde, the only available animal studies are two studies which are not following current guidelines. Two reports are available from closed 48 hour patch tests. In one, Veratraldehyde used at the concentration of 10% caused positive reactions in 1/11 patients, and in the other- none of the 97 tested individuals showed any reaction (concentration was not indicated in the report). For the source chemical, Piperonal, a well conducted LLNA test (OECD TG 429, GLP, K1) is available, showing the presence of skin sensitising potential (EC3 is 25%).

Target and Source chemical(s):

The target is Veratraldehyde, and the source is Piperonal. The information on the target and source substances, together with their physico-chemical properties, is presented in the data matrix below.

Purity / Impurities:

The substance is a mono-constituent: The impurities are below 2% (< 10%).

Analogue justification

According to REACH Annex XI, an analogue approach and structural alert information can be used to replace testing when information from different sources provides sufficient evidence to conclude that this substance has or does not have a particular dangerous property. The result derived should be applicable for C&L and/or risk assessment and be presented with adequate and reliable documentation.

Analogue selection:

Piperonal was selected because of the close structural similarity and adequate data were available. It was selected from all analogues identified in the OECD QSAR toolbox using Tanimoto similarity of 75% and analogues identified in the RIFM database.

Structural similarity and differences:

Veratraldehyde and Piperonal are both methyl phenyl aldehydes, with two ether bonds attached opposite the aldehyde group. The difference with Piperonal is that Veratraldehyde has two loose CH3 groups attached to the ether, while Piperonal has the ether bonds in a ring structure resulting in an acetal group.

Toxico-kinetic relevant for skin sensitization:

Both substances have similar dermal bioavailability based on their molecular weight and physico-chemical properties.

Toxico-dynamics:

Both substances are aldehydes and these aldehydes are predicted to have similar reactivity.

Remaining uncertainties:

There is no remaining uncertaintyas presented in the reasoning above.

Conclusions for skin sensitization on hazard and C&L

Piperonal is skin sensitising in a reliable LLNA with an EC3 of 25%. Based on read across also Veratraldehyde is expected to have an EC3 of 25%.

Final conclusion on hazard:  

Veratraldehyde is skin sensitizer and it needs to be classified and labelled for sensitisation with category 1B.

 

Data matrix Information on Veratraldehyde and Piperonal important for assessment of skin sensitizing properties

 

Name of substance	Veratraldehyde	Piperonal (Heliotropin)
Chemical structure
Cas no.	120-14-9	120-57-0
Einecs number	204-373-2	204-409-7
REACH registration	For 2018	Full registration
Empirical	C9H10O3	C8H6O3
Mol weight	166.18	150.13
Phys-chem
Appearance	solid (IFF, 2016)	solid
Melting point (^oC)	44.7°C (IFF, 2016)	36.5 (ECHA dissemination site)
Boiling point (^oC)	262.8°C (IFF, 2016)	272 (ECHA dissemination site)
Water solubility (mg/l)	14914 (IFF, 2016)	1400 (ECHA dissemination site)
Log Kow	0.8 (IFF, 2016)	1.2 (ECHA dissemination site)
Human health
Skin sensitisation	Read-across from Piperonal	EC3=25% (OECDTG 429)

 

Justification for classification or non-classification

Based on the results of the read-across substance, the substance is considered to be a sensitiser and should be classified as skin sensitizer (Category 1B) and labeled with H317: May cause an allergic skin reaction according to Regulation (EC) No. 1272/2008 and its amendments.