A mechanism of action of chemopreventive glucosinolates/isothiocyanates, established largely in vitro, is to modulate carcinogen-metabolising enzymes. Extrapolation in vivo involves relating in vitro concentrations to plasma/tissue concentrations attained in vivo, thus assuming that even transient exposure modulates enzyme activity. To test this hypothesis precision-cut rat liver slices were incubated with glucosinolates for up to 24 hours, and the O-dealkylation of methoxyresorufin and ethoxyresorufin determined; increased activities were observed only at incubations of at least 6 hours. To evaluate phase II enzymes, isothiocyanates, namely sulforaphane, erucin and phenethyl isothiocyanate, were similarly incubated; quinone reductase increased after incubation for 6 hours or longer. When glutathione S-transferase was monitored, the phenethyl isothiocyanate-manifested rise necessitated at least a 6-hour incubation, whereas in the case of sulforaphane and erucin activity was elevated after only 2 hours. It is inferred that a rise in carcinogen-metabolising enzymes by glucosinolates/isothiocyanates necessitates tissue exposure of at least 6 hours.
|Autori:||Abdull Razis, AF.;Bagatta, M.;De Nicola, GR.;Iori, R.;Plant, N.;Ioannides, C.|
|Data di pubblicazione:||2012|
|Titolo:||Characterisation of the temporal induction of hepatic xenobiotic-metabolising enzymes by glucosinolates and isothiocyanates: Requirement for at least a 6-hour exposure to elicit complete induction profile.|
|Rivista:||JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY|
|Appare nelle tipologie:||1.1 Articolo in rivista|