Phenethyl isothiocyanate (
PEITC) is an
isothiocyanate found in watercress as the
glucosinolate (
gluconasturtiin). The
isothiocyanate is converted from the
glucosinolate by intestinal microflora or when contacted with
myrosinase during the chopping and mastication of the vegetable.
PEITC manifested protection against chemically-induced
cancers in various tissues. A potential mechanism of
chemoprevention is by modulating the metabolism of
carcinogens so as to promote deactivation. The principal objective of this study was to investigate in rats the effect of
PEITC on
carcinogen-metabolising
enzyme systems such as
sulfotransferase (SULT), N-
acetyltransferase (
NAT), glucuronosyl
transferase (
UDP), and
epoxide hydrolase (EH) following exposure to low doses that simulate human dietary intake. Rats were fed for 2 weeks diets supplemented with
PEITC at 0.06 µmol/g (low dose, i.e., dietary intake), 0.6 µmol/g (medium dose), and 6.0 µmol/g (high dose), and the
enzymes were monitored in rat liver. At the Low dose, no induction of the SULT,
NAT, and EH was noted, whereas
UDP level was elevated. At the Medium dose, only SULT level was increased, whereas at the High dose marked increase in EH level was observed. It is concluded that
PEITC modulates
carcinogen-metabolising
enzyme systems at doses reflecting human intake thus elucidating the mechanism of its
chemoprevention.