Induction of epoxide hydrolase, glucuronosyl transferase, and sulfotransferase by phenethyl isothiocyanate in male Wistar albino rats.

Ahmad Faizal Abdull Razis,Noramaliza Mohd Noor,Nattaya Konsue

doi:10.1155/2014/391528

Ahmad Faizal Abdull Razis, Noramaliza Mohd Noor + Show 1 more

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https://doi.org/10.1155/2014/391528

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Abstract

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.

Highlights

Phenethyl isothiocyanate (PEITC) is a phytochemical with an aromatic side chain, found in cruciferous vegetables such as watercress, where it is present as a glucosinolate, so called gluconasturtiin [1]
Rats were treated with diets supplemented with 3 different doses, 0.06, 0.6, and 6.0 μmol PEITC/g diet for 14 days
The low dose is proportionate with human dietary intake of total glucosinolates, 75.5 mg/person/day or 1.07 mg/kg body weight for a 70 kg individual [29], which is comparable to an intake of 300 g watercress, the primary source of PEITC, based on 100 g watercress releasing approximately 25 mg PEITC [35]

Summary

Introduction

Phenethyl isothiocyanate (PEITC) is a phytochemical with an aromatic side chain, found in cruciferous vegetables such as watercress, where it is present as a glucosinolate, so called gluconasturtiin [1]. Whenever this vegetable is interrupted, for instance during mastication, the enzyme myrosinase (β-thioglucoside glucohydrolase) is released and induce the conversion of gluconasturtiin into PEITC as well as in the human intestine by microbial myrosinase [2]. The mercapturate of PEITC, an important metabolite, preserves its chemopreventive properties [12]

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