   In this study, several short-term microbial and mammalian in
vitro assays were used to evaluate cytotoxicity and genotoxicity
of four plant volatiles showing antifungal activity:
cinnamaldehyde, carvacrol, thymol and S(+)-carvone. All
inhibited viability and proliferation of Hep-2 cells in a dose-
dependent manner. IC50 ranged from 0.3 mM (cinnamaldehyde) to
0.7 mM (thymol) in viability tests and from 0.2 mM (carvacrol)
to 0.9 mM (carvone) in the proliferation test. The morphological
analysis suggested an involvement of apoptosis in the cases of
carvone, carvacrol and cinnamaldehyde. At nontoxic doses,
carvacrol and thymol increased the number of revertants in the
Ames test by 1.5-1.7 times, regardless of metabolic activation.
In the SOS-chromotest, none of the four plant volatiles caused
DNA damage at non-toxic doses. In the DNA repair test, a marked
dose-dependent differential toxicity was observed with carvone
and, to a lesser extent, with cinnamaldehyde, while with thymol
and carvacrol, this effect was