Melaleuca viridiflora extract

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15 September – 04 October 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study conducted in compliance with OECD guideline 429.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

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: Elevage Janvier, France
- Age at study initiation: 8 weeks
- Weight at study initiation: 19.3-22.1 g
- Housing: Individually housed in suspended solid-floor polypropylene cages
- Diet (e.g. ad libitum): Diet (M20, SDS), ad libitum
- Water (e.g. ad libitum): Tap water, ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25 °C
- Humidity (%): 30-70 %
- Air changes (per hour): 15/hour
- Photoperiod (hours dark / hours light): 12 hours dark / 12 hours light

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

0, 5, 10, 25, 50 and 100 % (v/v) in acetone/olive oil (4:1, v/v)

No. of animals per dose:

Four females

Details on study design:

RANGE FINDING TESTS:
- Method: In the preliminary test, a mouse was treated with daily application of 25 µL of the test item (undiluted) to the dorsal surface of each ear for three consecutive days (Days 1, 2 and 3). Any signs of toxicity or excessive local irritation were recorded daily on Days 1, 2, 3, 4, 5 and 6. Ear thickness was recorded on Days 1, 3 and 6. Bodyweight of the mouse was recorded on Day 1 (prior to dosing) and on Day 6.
- Results: No systemic toxicity or excessive irritation was noted at 100 %. Therefore, the concentration of 100 % was chosen as the highest concentration for the main study.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local Lymph Node Assay
- Criteria used to consider a positive response: Test item would be regarded as a sensitiser if at least one concentration of the test item produce a Stimulation Index > 1.4 (SI = cell count of treated group / cell count of control group).

TREATMENT PREPARATION AND ADMINISTRATION: 25 µL of test material at concentrations of 0 (vehicle control), 5, 10, 25, 50 and 100 % (v/v) in acetone/olive oil (4:1, v/v) were applied to the dorsal surface of each ear on Days 1, 2 and 3. On Day 6, all mice were euthanized with sodium pentobarbital and the draining auricular lymph node from the four mice were excised and pooled for each experimental group. A single cell suspension of the lymph node cells of 4 mice of each group was prepared by gentle mechanical tissue disaggregation through a 200-mesh cell strainers in 4 mL of PBS (Ca2+ / Mg2+ free) containing 0.5 % BSA into a well of a multi-well 6. A volume of 10 μL of this cell suspension was diluted in 10 mL of physiological saline solution (NaCl 0.9 %). The lymphocyte cells were counted using a cell counter (Beckman Coulter Z2).

Positive control substance(s):

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

Statistics:

Not applicable

Positive control results:

Stimulation Index = 2.06

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

- Stimulation Index (SI) calculated by pooled approach was 1.18, 0.96, 1.01, 1.52 and 2.35 for the treated groups at 5, 10, 25, 50 and 100 %, respectively. - EC1.4 value determined by linear interpolation of points on the dose-response curve was 44.12 %.

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Not applicable

- Clinical signs and mortality: No mortality and no signs of systemic toxicity were noted in the test and controls animals during the test.

- Body weight: Bodyweight changes of the test animals were comparable to those observed in the corresponding control group animals, throughout the study.

- Skin irritation and ear thickness: Slight dryness to dryness was noted on the treatment site on Day 6 in all animals treated at 100 %. No significant increase in ear thickness and in ear weight was recorded at the concentrations up to 100 %.

Interpretation of results:

sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the test conditions, NIAOULI Essential Oil (Melaleuca quinquenervia) 021261 is classified as ‘R43 May cause sensitisation by skin contact’, according to the criteria of Annex VI to the Directive 67/548/EEC and ‘Category 1’ according to the Regulation (EC) No 1272/2008 (CLP).

Executive summary:

In a local lymph node assay performed in CBA/J strain mice according to OECD guideline 429 and in compliance with GLP, six groups of mice (4 females/dose) were applied with 25 µL of the test item, NIAOULI Essential Oil (Melaleuca quinquenervia) 021261, at concentrations of 0 (vehicle control), 5, 10, 25, 50 and 100 % (v/v) in acetone/olive oil (4:1, v/v) (AOO) to the dorsal surface of each ear for three consecutive days. A group of 4 mice was treated with a positive control (alpha-hexylcinnamaldehyde) diluted at 25 % (v/v) in AOO. On Day 6, all animals were sacrificed and the proliferation of lymphocytes in the draining auricular lymph nodes was determined by cell counting.

No mortality or clinical sign of toxicity was noted at any dose level. No significant increase in ear thickness and in ear weight was recorded at any dose level. Stimulation Index (SI) calculated by pooled approach was 1.18, 0.96, 1.01, 1.52 and 2.35 for the treated groups at 5, 10, 25, 50 and 100 %, respectively, and EC1.4 value was determined to be 44.12 %. The SI value for the positive control was 2.06.

Under the test conditions, NIAOULI Essential Oil (Melaleuca quinquenervia) 021261 is classified as ‘R43 May cause sensitisation by skin contact’, according to the criteria of Annex VI to the Directive 67/548/EEC and ‘Category 1’ according to the Regulation (EC) No 1272/2008 (CLP).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

A key study was identified (Colas, 2011, Rel.1). In this local lymph node assay performed using a non-radioactive method according to OECD guideline 429 and in compliance with GLP, mice were applied with Niaouli oil at concentrations of 0 (vehicle control), 5, 10, 25, 50 and 100 % (v/v) in acetone/olive oil (4:1, v/v) (AOO) to the dorsal surface of each ear for three consecutive days. A group of mice was treated with a positive control (alpha-hexylcinnamaldehyde) diluted at 25 % (v/v) in AOO. On Day 6, all animals were sacrificed and the proliferation of lymphocytes in the draining auricular lymph nodes was determined by cell counting.

No mortality or clinical sign of toxicity was noted at any dose level. No significant increase in ear thickness and in ear weight was recorded at any dose level. Stimulation Index (SI) calculated by pooled approach was 1.18, 0.96, 1.01, 1.52 and 2.35 for the treated groups at 5, 10, 25, 50 and 100 %, respectively, and EC1.4 value was determined to be 44.12 %. The SI value for the positive control was 2.06.

With a SI ≥1.4 at concentrations ≥50%, Niaouli oil is considered to be a skin sensitiser under the test conditions (LLNA - non-radioactive method).

This conclusion is supported by a case-report (Dharmagunawardena, 2002), in which a patient presented with suspected allergic contact dermatitis showed a positive reaction (oedematous/vesicular reaction) on Day 4 with Niaouli oil.

Migrated from Short description of key information:
- skin sensitisation: sensitising (OECD 429, GLP, K, rel.1).

Justification for selection of skin sensitisation endpoint:
Only one study available. The key study is GLP-compliant and of high quality (Klimsic score = 1).

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Harmonized classification:

Niaouli oil has no harmonized classification according to the Regulation (EC) No. 1272/2008.

Self-classification:

Based on the available information Niaouli oil is classified as skin sensitizer:

- May cause sensitisation by skin contact (Xi; R43) according to the criteria of the Annex VI of the Directive 67/548/EEC,

- Skin Sens. 1B, H317 (May cause an allergic skin reaction) according to the criteria of the Regulation (EC) No. 1272/2008 (CLP).

No information was available regarding respiratory sensitisation.