Safety evaluation of certain food additives - ipcs inchem

ALKOXY-SUBSTITUTED ALLYLBENZENES 433
Increases in SCE in the presence of 0.5–810 μg safrole/ml were reported in CHO,
Chinese hamster V79 and human hepatoma strain G2 cells (Gulati et al., 1985; van
Went, 1985; Jain, 1989; Natarajan & Darroudi, 1991). In one of these studies, the
authors noted that the results, while positive, did not follow a concentrationdependent
increase in SCE induction (Jain, 1989). In another study, the authors
noted that the assay was positive only at the lowest concentration, 0.1 mmol/l; at
higher concentrations, there were not enough metaphases to evaluate SCE. Mitotic
indices were reduced by as much as 80% (Natarajan & Darroudi, 1991).
In vitro micronucleus induction studies with 0.162–243 μg safrole/ml showed
mixed results. In two studies using CHO cells, no induction of micronuclei was
observed in the presence or absence of metabolic activation (Douglas et al., 1985;
Kevekordes et al., 2001). In one study using human hepatoma G2 cells, induction
of micronuclei was reported to occur in a concentration-dependent manner
(Natarajan & Darroudi, 1991).
No evidence of chromosomal aberration was observed in the majority of
reported studies for safrole at concentrations ranging from 0.16 to 300 μg/ml in CHO,
Chinese hamster fibroblast, RL1 and Chinese hamster V79 cells (Dean, 1981;
Nararajan & van Kesteren-van Leeuwen, 1981; Danford, 1985; Gulati et al., 1985;
Parry, 1985; Jain, 1989). Three studies reported the occurrence of chromosomal
aberrations when 16.2–486 μg safrole/ml was incubated with CHO, Chinese
hamster lung fibroblast and rat hepatocyte cells (Ishidate & Sofuni, 1985; Palitti et
al., 1985; Bradley et al., 1987).
UDS in hepatocytes observed following treatment of rodents with alkoxysubstituted
allylbenzenes is most likely produced by CYP-mediated metabolism of
the compounds to 1-hydroxy metabolites. The dose–response for UDS is nonlinear,
and it is therefore important to consider the dose–response relationship for
formation of the 1-hydroxy metabolite.
Elemicin increased the occurrence of UDS in rat hepatocytes at
concentrations of 0.208–2083 μg/ml. The authors observed that UDS displayed
concentration-dependent increases up to 104 μg/ml (500 μmol/l). At higher
concentrations, marked cytotoxicity was observed, as manifested by increased LDH
leakage (Hasheminejad & Caldwell, 1994). In the same study, 0.192–1922 μg
myristicin/ml showed no increase in UDS levels, but the authors observed
cytotoxicity at concentrations of 192 μg/ml (0.001 mol/l) (Hasheminejad & Caldwell,
1994). A marked increase in UDS was reported when estragole at concentrations
of 10 3 –10 5 mol/l was incubated with primary rat hepatocytes (Müller et al., 1994).
Freshly prepared hepatocytes from male Fischer 344 rats were incubated
with methyl eugenol, safrole and estragole at concentrations in the range from
10 6 to 10 2 mol/l (Chan & Caldwell, 1992). A significant increase in UDS, as much
as 2.7 times control values, occurred at concentrations in the range from 10 4 to
10 2 mol/l for both substrates. Cytotoxicity, as measured by leakage of cytosolic
LDH from hepatocytes, was observed at concentrations in the range from 10 4 to
10 2 mol/l. Incubation with the 1-hydroxy metabolites of methyl eugenol and
estragole showed increased UDS at concentrations above 10 5 mol/l and
above 10 5 –10 6 mol/l, respectively. LDH leakage occurred at 10 4 mol/l for 1-