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Diss Factsheets

Administrative data

Endpoint:
genetic toxicity in vivo
Remarks:
Type of genotoxicity: other: gene mutation chromosome aberration DNA damage and/or repair
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The methods reasonably state the materials/animals used and sufficient detail to understand exactly what was done.
Cross-reference
Reason / purpose for cross-reference:
reference to other study

Data source

Reference
Reference Type:
publication
Title:
Genotoxicity of cocoa examined by microbial and mammalian systems
Author:
H. W. Renner and R. Münzner
Year:
1981
Bibliographic source:
Mutation Research, 103 (1982) 275-281

Materials and methods

Test guideline
Qualifier:
no guideline followed
Guideline:
other: Not applicable
Deviations:
not applicable
GLP compliance:
no
Type of assay:
other: sister chromatid exchange assay in mammalian cells other: in vivo mammalian chromosome aberration test in vivo mammalian cell micronucleus test

Test material

Constituent 1
Reference substance name:
Cocoa powder (fat free)
IUPAC Name:
Cocoa powder (fat free)
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
- Name of test material (as cited in study report): cocoa powder roasted and unroasted, fat free (fat extracted with petroleum) cocoa butter
- Physical state: powder/solidsolid
- Analytical purity: no data, suitable for use in foodpuriss.

- Radiochemical purity (if radiolabelling): no data
- Specific activity (if radiolabelling): no data
- Locations of the label (if radiolabelling): no data
- Expiration date of radiochemical substance (if radiolabelling): no data
- Stability under test conditions: no data
- Storage condition of test material: no data
- Other:

Test animals

Species:
other: Species/strain: other: Chinese hamster polychromatic erythrocytes Chinese hamster bone marrow cells

Administration / exposure

Route of administration:
other: Stomach tube
Vehicle:
Water and Corn oil.
Frequency of treatment:
-dosage: theobromine – single dose, 2h after BrdU implantation; cocoa powder – 0.1 or 0.2 g/animal at the same time with the BrdU implantation, followed by 2 other administrations of 0.2 g each at 90 minutes intervals; (total doses 0.1; 0.3; 0.4 and 0.6g

Results and discussion

Additional information on results:
Species / strain:
other:
Chinese hamster polychromatic erythrocytes
Chinese hamster bone marrow cells




Metabolic activation:
with and without

Test system:
all strains/cell types tested

Genotoxicity:
Positive sister chromatid exchangeambiguous

Cytotoxicity:
no data

Vehicle controls valid:
not examined

Negative controls valid:
no data

Positive controls valid:
yes

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): other: The only result was a positive sister chromatid exchange (SCE) in vivo. No OECD method has been developed for this assay due to the high degree of variability in the results seen with the in vivo assay. The mechanisms driving the SCE are not known and an
The positive SCE was the only positive in vivo assay cocoa powder being negative in the in vivo mammalian chromosome aberration assay and the in vivo mammalian micronucleus assay. In the current ICH guidance on genotoxicity testing a negative in vivo micronucleus assay would be considered to be a good indication of a lack of genotoxicity with negative findings found in the in vitro assays (Ames, in vitro micronucleus or mouse lymphoma), This SCE positive result needs to be considered in the light of other studies.
Executive summary:

Unroasted or roasted cocoa powder dispersed in water and applied to Chinese hamsters by stomach tube caused elevated numbers of SCEs in the sister-chromatid exchange test (bone-marrow cells). Roasted cocoa freed from fat produced distinctly higher SCE values with a linear dose-response relationship, whereas cocoa butter had no influence on SCE levels. Positive results in the SCE test (1.5-fold values of the controls) were obtained after application of about 5 g cocoa/kg b.w. Positive test results were not found when cocoa was given in the diet instead of being administered by stomach tube. No evidence of genotoxicity was seen in the in vivo micronuclueus assay (max dose 0.6 g/animal) or in an in vivo mammalian chromosome aberration test (0.2 g/animal)The exact mechanisms driving the SCE assay are not known and an increase in SCE does not necessary indicate genotoxicity, which makes a positive result difficult to interpret on its own. This assay has an OECD guideline but only for the in vitro version of the test. The in vivo assay is no longer routinely performed.

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