p-menth-1-en-4-ol

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / micronucleus study

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

In vitro genotoxicity of Melaleuca alternifolia essential oil in human lymphocytes

Author:

Pereira T. S., Rocha de Sant'Anna J, Silva E. L., Pinheiro A. L., Alves de Castro-Prado M. A.

Year:

2014

Bibliographic source:

Journal of Ethnopharmacology 151 (2014) 852–857

Report date:

2013

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 487 (In vitro Mammalian Cell Micronucleus Test)

Deviations:

yes

Remarks:

no metabolic activation used

GLP compliance:

not specified

Type of assay:

in vitro mammalian cell micronucleus test

Test material

Test material information

Constituent 1

Reference substance name:

Melaleuca Alternifolia /Tea Tree) Leaf oil

Cas Number:

68647-73-4

IUPAC Name:

Melaleuca Alternifolia /Tea Tree) Leaf oil

Method

Species / strain

Species / strain / cell type:

lymphocytes: human

Details on mammalian cell type (if applicable):

CELLS USED
- Sex, age and number of blood donors: Male (2), female (1), aged 25 years

Test concentrations with justification for top dose:

95, 182, and 365 µg/ml

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

no

True negative controls:

no

Positive controls:

yes

Positive control substance:

mitomycin C

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Preincubation period: 24 h
- Exposure duration: 20 h
- Blockage of cytokinesis: At 44 h (with cytochalasin B)
- Incubation time, total: 72 h

ACTIN FILAMENT INHIBITOR: cytochalasin B (final concentration 6 µg/ml)

STAIN: 5% Giemsa (pH 6.8)

NUMBER OF REPLICATIONS: 3

NUMBER OF CELLS EVALUATED: 1000 each (a total of 3000 cells per concentration)

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index
- Any supplementary information relevant to cytotoxicity: Mitotic index was calculated by the number of dividing cells/total number of the cells x 100

Evaluation criteria:

The cytokinesis block proliferation index (CBPI) was determined as follows: CBPI=N1+2N2+3(N3+N4)/500, where N1–N4 are the cells with one to four nuclei in 500 cells counted for each experiment.
The amount of cytostasis was determined as follows: % cytostasis=100-100 [(CBPI(T)-1)/(CBPI(C)-1)], where CBPI(T) was the CBPI rate of treatment and CBPI(C) was the CBPI rate of negative control.

Statistics:

Data were expressed as frequencies of micronuclei and mean +/- standard deviation (SD) of the mean for buds and CBPI rates. Results were statistically analyzed by Z-test and the non-parametric Kruskal–Wallis test (p<0.05).

Results and discussion

Test results

Species / strain:

lymphocytes: human

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 365 µg/ml

Untreated negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

The chemical composition of the tea tree oil was determined and the main constituent was observed to be terpinen-4 -ol with 42.8%.

Applicant's summary and conclusion

Conclusions:

Tea tree oil was tested negative under the conditions chosen in this micronucleus assay and thus, was considered to be non-mutagenic.

Executive summary:

The genotoxic potential of tea tree oil was investigated by the in vitro chromosome aberration assay using human lymphocytes derived from donors. Subjects were non-smoking, non-alcoholic, not under drug therapy and without recent history of exposure to mutagens. Human lymphocytes were treated with three concentrations ( 95, 182, and 365 µg/m) in triplicate. None of the concentrations caused a significant increase in the observed frequencies of micronuclei when compared to the negative control. The positive control mytomicin C induced a significant response. Cytotoxicity was observed at 365 µg/ml.