Assessment of genotoxic potential of fragrance materials in the Chicken
Egg Assays
Abstract
The genotoxic and clastogenic/aneugeneic potentials of four α,
ß-unsaturated aldehydes, 2-phenyl-2-butenal, nona-2-trans-6-cis-dienal,
2-methyl-2-pentenal and p-methoxy cinnamaldehyde, which are used as
fragrance materials, were assessed in avian fetal livers using the
Chicken Egg Genotoxicity Assay (CEGA) and the Hen’s egg micronucleus
(HET-MN) assay, respectively. Selection of materials was based on their
chemical structures and the results of their assessment in the
regulatory in vitro and/or in vivo genotoxicity test
battery. Three tested materials, 2-phenyl-2-butenal,
nona-2-trans-6-cis-dienal and 2-methyl-2-pentenal, were negative in
both, CEGA and HET-MN assays. These findings were congruent with the
results of regulatory in vivo genotoxicity assays. In contrast,
p-methoxy cinnamaldehyde, which was also negative in the in vivo
genotoxicity assays, produced evidence of DNA damage, including DNA
strand breaks and DNA adducts in CEGA, however, no increase in the
micronucleus formation in blood was reported in the HET-MN study.
Pretreatment with a glutathione precursor, N-acetyl cysteine, negated
positive outcomes produced by p-methoxy cinnamaldehyde in CEGA,
indicating that difference in response observed in the egg and rodent
models can be attributed to rapid glutathione depletion. Additionally,
the dosing protocols for both HET-MN and CEGA assays are different,
which can also be an important contributing factor. Overall, our
findings support the conclusion that CEGA and/or HET-MN can be
considered as a potential alternative to animal testing as follow-up
strategies for assessment of genotoxic potential of fragrance materials
with evidence of genotoxicity in vitro.