Commiphora myrrha, ext.

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

key study

Study period:

No data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

purity of test substance; details of acclimation; environmental conditions; evaluation criteria not reported

Data source

Reference

Reference Type:

publication

Title:

Evaluation of the genotoxic, cytotoxic, and antitumor properties of Commiphora molmol using normal and Ehrlich ascites carcinoma cell-bearing Swiss albino mice.

Author:

Qureshi S, al-Harbi MM, Ahmed MM, Raza M, Giangreco AB and Shah AH.

Year:

1993

Bibliographic source:

Cancer Chemother Pharmacol. 33(2):130-138.

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

yes

Remarks:

composition of test substance; details of acclimation; environmental conditions; evaluation criteria not reported

Principles of method if other than guideline:

Not applicable

GLP compliance:

not specified

Type of assay:

mammalian germ cell cytogenetic assay

Test material

Test material information

Constituent 1

Reference substance name:

Resinoid of Commiphora myrrha (Burseraceae) obtained from the gum by ethanol extraction

EC Number:

944-530-9

Cas Number:

84929-26-0

Molecular formula:

not applicable for UVCB

IUPAC Name:

Resinoid of Commiphora myrrha (Burseraceae) obtained from the gum by ethanol extraction

Test material form:

solid

Details on test material:

- Name: C. Molmol
- Source: collected from the local market in Riyadh, Saudi Arabia

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source of test material: Samples of oleo gum resin (Commiphora molmol) was collected from a local market in Riyadh, Saudi Arabia.

Test animals

Species:

mouse

Strain:

Swiss

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Experimental Animal Care Center, King Saud University, Saudi Arabia.
- Age at study initiation: 5-6 weeks
- Weight at study initiation: 20-25 g
- Assigned to test groups randomly: Yes; animals were randomly assigned to different control and treatment groups
- Diet: Purina chow diet, ad libitum
- Water, ad libitum

ENVIRONMENTAL CONDITIONS
- Animals were maintained under standard conditions of humidity, temperature, and light (12 h light/12 h dark cycle).

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: Distilled water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Test substance was given orally to animals as a fresh aqueous suspension.

Duration of treatment / exposure:

7 days

Frequency of treatment:

Daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

125 mg/kg bw/day

Doses / concentrations 2

Dose / conc.:

250 mg/kg bw/day

Doses / concentrations 3

Dose / conc.:

500 mg/kg bw/day

No. of animals per sex per dose:

5 females/dose

Control animals:

yes, concurrent vehicle

Positive control(s):

- Positive control: Cyclophosphamide
- Route of administration: Intraperitoneal
- Doses / concentrations: 100 mg/kg bw
- CP was injected 30 h before the animals were killed.

Examinations

Tissues and cell types examined:

The polychromatic erythrocytes (PCE/1000 per mouse) were screened for micronuclei, and reduction of the mitotic index was assessed on the basis of the ratio of polychromatic to normochromatic erythrocytes (PCE/NCE ratio).

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION:
The highest dose of oleo gum resin used in the present study (500 mg/kg bw/day) had previously been reported to be pharmacologically active and was found to be effective in a preliminary study on its cytotoxic activity.

TREATMENT AND SAMPLING TIMES:
In each case, animals were killed 30 h after the last treatment. The femurs were used for a micronucleus test

DETAILS OF SLIDE PREPARATION:
The micronucleus test procedure described by Schmid was followed. The femoral cells were collected in fetal calf serum. After centrifugation, the cells were spread on slides and air-dried. Coded slides were fixed in methanol and stained in May-Gruenwald solution followed by Giemsa stain.

METHOD OF ANALYSIS:
The polychromatic erythrocytes (PCE/1000 per mouse) were screened for micronuclei, and reduction of the mitotic index was assessed on the basis of the ratio of polychromatic to normochromatic erythrocytes (PCE/NCE ratio).

Statistics:

Statistical analysis was performed with Student's t-test.

Results and discussion

Test results

Key result

Sex:

female

Genotoxicity:

negative

Toxicity:

yes

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay):Test substance caused no significant difference in the incidence of micronucleated PCE in femoral cells of normal mice as compared with the controls.
- Ratio of PCE/NCE (for Micronucleus assay): There was a statistically significant decrease in the PCE/NCE ratio in the treatment groups, indicating the cytotoxic potential of test substance.
- Positive control: Cyclophosphamide significantly increased the number of micronucleated PCE and decreased the PCE/NCE ratio.

Any other information on results incl. tables

Table 7.6.2/1: Micronucleus test – results

Groups	Treatment and dose (mg/kg day)	PCE screened	Percentage of micronucleated PCE (mean ± SE)	NCE screened	PCE/NCE ratio (mean ± SE)
1	Control (Distilled water)	5996	0.43 ± 0.04	5690	1.10 ± 0.09
2	Cyclophosphamide 100	4472	4.20 ± 0.23***	6700	0.67 ± 0.10**
Test substance
3	125	5300	0.28 ± 0.09	6500	0.81 ± 0.10*
4	250	5000	0.30 ± 0.06	6600	0.76 ± 0.12*
5	500	5600	0.33 ± 0.02	8000	0.72 ± 0.08**

Groups 2, 3, 4, and 5 were statistically compared with group 1. Five mice were used in each group

*P <0.05, **P <0.01, ***P <0.001; Student's t-test

Applicant's summary and conclusion

Conclusions:

Under the test conditions, test substance did not show any evidence of causing an increase in the induction of micronucleated polychromatic erythrocytes in mice.

Executive summary:

In an in vivo micronucleus test conducted similarly to OECD 474 guideline, Swiss mice (5 females/dose) were administered with test substance by oral (gavage) at the dose levels of 125, 250 and 500 mg/kg bw/day for 7 days. Vehicle control group was administered with distilled water and positive control groups were given cyclophosphamide (100 mg/kg bw, IP). Animals were sacrificed 30 h after the last treatment and the femurs were used for a micronucleus test. The polychromatic erythrocytes (PCE/1000 per mouse) were screened for micronuclei, and reduction of the mitotic index was assessed on the basis of the ratio of polychromatic to normochromatic erythrocytes (PCE/NCE ratio).

There was a statistically significant decrease in the PCE/NCE ratio in the treatment groups, indicating the cytotoxic potential of test substance. Test substance caused no significant difference in the incidence of micronucleated PCE in femoral cells of normal mice as compared with the controls. Cyclophosphamide significantly increased the number of micronucleated PCE and decreased the PCE/NCE ratio.

 

Under the test conditions, test substance did not show any evidence of causing an increase in the induction of micronucleated polychromatic erythrocytes in mice.