Effects of dietary broccoli on rat testicular xenobiotic metabolizing enzymes

Abstract

The effects of vegetables on the activities of various metabolizing enzymes in liver and intestine have been studied intensively, whereas studies on effects on testicular metabolizing enzymes are lacking. The present report is the first describing the effects of dietary broccoli on the activities of a number of xenobiotic metabolizing enzymes from rat testes. Groups of male Wistar rats were fed a semisynthetic diet with 10% (w/w) freeze-dried broccoli for 1 week. Different broccoli samples with varying content of glucosinolates were used. Dietary broccoli significantly increased the activities of two testicular phase II enzymes--glutathione S-transferase (1.6-fold) and UDP-glucuronosyl transferase (1.8-fold). The activities of these enzymes differed significantly depending on the conditions during cultivation of the broccoli, because of differences in the content of glucosinolates and other secondary plant metabolites. The levels of two glutathione S-transferase subunits, rGSTM2 and rGSTA, were determined using Western blotting analysis and the levels of both subunits were reduced in animals fed broccoli grown at low S-fertilizer level. Broccoli did not statistically significantly modulate the activities of the phase I enzymes, epoxide hydrolase or NAD(P)H quinone-oxidoreductase, or the phase II enzyme p-sulphotransferase, or the anti-oxidative enzymes catalase and total glutathione peroxidase in rat testes. In general, dietary broccoli affects phase I and phase II enzyme levels in rat testes much less than found in liver, however, two rat testicular phase II xenobiotic metabolizing enzymes were induced.

Dietary broccoli mildly improves neuroinflammation in aged mice but does not reduce lipopolysaccharide-induced sickness behavior

“…This is particularly important because SFN is not stable and is more bioactive when fed to rats in its glucosinolate precursor form than when hydrolyzed prior to being fed to rodents [34]. Addition of 10–20% freeze-dried broccoli to rodent diet has been reported to increase activity of hepatic and colonic ARE enzymes [58–60]. In contrast to these reports, 10% broccoli diet utilized in our studies did not increase ARE genes in brain or liver tissue of aged mice.…”

Food Matrix Effects on Bioactivity of Broccoli-Derived Sulforaphane in Liver and Colon of F344 Rats

“…When male F344 rats were given SF daily by gavage for 5 days, 500 or 1000, but not 200, µmol of SF/kg of BW caused significant increases in hepatic, pancreatic, and colonic QR and GST activities (18). Yet freezedried broccoli, added to the rodent diet at 10 or 20% and providing <200 µmol of SF/kg, has consistently been reported to up-regulate phase II detoxification enzymes such as GST and QR (4,19). Bioavailability, efficacy, and potency of glucosinolate hydrolysis products have not been addressed in detail.…”

Glucosinolate profiling of seeds and sprouts of B. oleracea varieties used for food

“…Transformation products from aliphatic glucosinolates have been shown to be particularly potent inducers of phase 2 enzymes (Barillari et al, 2005;Fahey et al, 1997;Staack et al, 1998;Talalay et al, 1995;Zhang et al, 1992) whereas hydrolysis products from indol-3-ylmethylglucosinolates are bifunctional inducers (Bonnesen et al, 1999;Prestera et al, 1993;Vang et al, 1995;Vang et al, 2001). In order to optimize the length of the sprouting period for maximum concentration of a particular group of glucosinolates it is therefore crucial to identify the individual glucosinolates present in brassicaceous sprouts.…”

“…Under certain experimental conditions, crambene, the nitrile derived from epi-progoitrin has shown similar effects to sulphoraphane . Other glucosinolate hydrolysis products, such as indol-3-ylcarbinol (I3C) and/or its derivatives produced in the hydrolysis of indol-3-ylmethylglucosinolates (Buskov et al, 2000a;Buskov et al, 2000b), show however a dual effect: at the same time as inducing phase 2 enzymes (Vang et al, 1995;Wortelboer et al, 1992) or contributing to cancer cell cycle arrest (Cover et al, 1998), they have also been associated to a higher risk of cancer development due to the induction of phase 1 enzymes, which are responsible for activation of carcinogens (Kim et al, 1997;Lee and Park, 2003;Stoewsand, 1995).…”