Food matrix effects on bioactivity of broccoli-derived sulforaphane in liver and colon of F344 rats.
Sulforaphane (SF) is considered to be the major anticarcinogenic component in broccoli. The effects of feeding rats purified SF (5 mmol/kg of diet), broccoli containing SF formed in situ during laboratory hydrolysis (broccoli-HP; 20% freeze-dried broccoli diet, 0.16 mmol of SF/kg of diet), and broccoli containing intact glucosinolates (broccoli-GS; 20% freeze-dried broccoli diet, 2.2 mmol of glucoraphanin/kg of diet) were compared. Rats (male F344 rats, five per group) were fed control (modified AIN-76 B-40), SF, broccoli-HP, or broccoli-GS for 5 days. In rats fed broccoli-GS, quinone reductase activities (QR) in the colon and liver were greater (4.5- and 1.4-fold over control, respectively) than in rats fed broccoli-HP (3.2- and 1.1-fold over control, respectively). Broccoli-GS and SF diets increased QR to the same extent, even though the broccoli-GS diet contained far less SF (as the unhydrolyzed glucosinolate, glucoraphanin) than the purified SF diet. In a second experiment, rats were fed one of six diets for 5 days: (1) control; (2) 20% broccoli-GS; (3) diet 2 + low SF (0.16 mmol/kg of diet); (4) diet 2 + high SF (5 mmol/kg of diet); (5) low SF (0.32 mmol/kg of diet); or (6) high SF (5.16 mmol/kg of diet). In both liver and colon, QR was increased most by high SF plus broccoli-GS; individually, high SF and broccoli-GS had similar effects, and adding the low-dose SF to broccoli-GS had either no effect or a negative effect. In both experiments, urinary SF-mercapturic acid correlated with QR activity, not with dietary intake. It was concluded that all diets were substantially more effective in the colon than in the liver and that broccoli-GS was more potent than SF or broccoli-HP.
Keck
Anna-Sigrid
AS
Division of Nutritional Sciences, University of Illinois, Urbana, Illinois 61801, USA.
Qiao
Qingyan
Q
Jeffery
Elizabeth H
EH
D000818:Animals; D001937:Brassica / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003106:Colon / Q000187:drug effects* / Q000201:enzymology; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D004032:Diet; D005961:Glucosinolates / Q000008:administration & dosage; D017879:Isothiocyanates; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D013454:Sulfoxides; D013861:Thiocyanates / Q000008:administration & dosage*
D005961:Glucosinolates; D017879:Isothiocyanates; D013454:Sulfoxides; D013861:Thiocyanates; D019363:Cytochrome P-450 CYP1A1; D016660:NAD(P)H Dehydrogenase (Quinone); C016766:sulforaphane