Anticancer enzyme-based dietary manipulating strategies: from the cruciferae extract to the isolated single constituent

Epidemiological and animal studies linking high and varied fruit and vegetable intake to lower cancer risk, suggest the theoretical possibility that regular, long-term mass administration of isolated naturally occurring dietary constituents can provide a means of controlling cancer incidence. Although no exact mechanism of molecular chemoprotection is known, it is believed that the up-regulation of phase-II metabolizing enzymes by phytoalexins, such as sulforaphane - released from its thioglucoside natural precursor, glucoraphanin, by myrosinase hydrolysis – an isothiocyanate found in Cruciferae, could provide a defence against carcinogens.With the aim to verify such hypothesis, the effects of glucoraphanin supplementation on xenobiotic metabolizing enzymes were thus investigated in male and female Sprague-Dawley rats (aged 6-7 weeks, 150±15 g) receiving per os daily either 24 or 48 mg/kg b.w. glucoraphanin and, for comparison, either 120 or 240 mg/kg b.w. of the palmizio cauliflower extract (PCE – OD74 containing the same amount of glucoraphanin) for four consecutive days; controls received saline only and liver microsomes tested for various CYPs.Glucoraphanin slightly affected phase-II “detoxifying” enzymes, but powerfully induced phase-I bioactivating enzymes (P