Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2002
Publication Date: 3/22/2002
Citation: Keck, A.S., Hintze, K.J., Finley, J.W., Jeffery, E. 2002. Dietary broccoli and pure sulforaphane upregulated detoxification enzymes and thioredoxin reductase, but decreased glutathione peroxidase when fed to f344 rats [abstract]. Journal of Federation of American Societies for Experimental Biology. 16(5):A1007.
Technical Abstract: Broccoli consumption, the primary source of sulforaphane (SF), correlates with lowered risk of cancer. We compared the effects of pure SF and SF in broccoli on detoxification and antioxidant enzymes. Rats were fed for 5 d: control (1), 20% broccoli (2), 3.2 umol SF/d (3), 51.6 umol SF/d (4), 20% broccoli+1.6 umol SF/d (5) or 20% broccoli+50 umol SF/d (6). Rats fed broccoli (diet 2, 5, 6) or pure SF (diet 4) had significantly increased quinone reductase (QR) activity in colon (1.8-2.9 fold) and a similar pattern was found in liver but to a lower extent (1.1-1.8 fold). Compared to control, broccoli, but not pure SF, significantly elevated cytochrome P4501A activities (1.2-1.5 fold). Although dietary selenium contents were similar (0.13-0.19 ppm), thioredoxin reductase (TR) activity was significantly increased 1.8 to 2.8 fold by broccoli (diet 2, 5, 6) and pure SF (diet 3). There was a positive correlation between SF excreted as SF mercapturate (SF-M) in the urine and QR activity in liver (p=0.0006) and colon (p<0.0001), a negative correlation between SF-M and glutathione peroxidase activity (p=0.002). We conclude that broccoli may promote human health by other mechanisms than through detoxification.