Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 12/1/2003
Publication Date: 3/24/2004
Citation: Finley, J.W., Hintze, K.J., Robbins, R.J., Keck, A. 2004. Activation of antioxidant responsive element (are) -regulated genes by bioactive components in broccoli - effects of fertilization with selenium (se) [abstract]. The Federation of American Societies for Experimental Biology Journal. 18:A892.
Technical Abstract: Broccoli consumption may reduce cancer; a potential mechanism is ARE-mediated transcriptional up-regulation of antioxidant enzymes by compounds such as sulforaphane (Sf). Se and Sf also up-regulate TR activity through translation. Other compounds that activate the ARE are uncharacterized; the effect of Se fertilization (increasing the Se from <2 to >500 µg Se/g broccoli) on the accumulation of bioactive compounds in broccoli is unknown. Derivatives of phenolic acids (PA) were determined by LC-MS in full scan and single ion monitoring modes. Relative to control broccoli, Se fertilization increased glycosylated flavonoids; fertilization decreased Sf by almost 80%. Broccoli extracts, purified Sf, ascorbic acid and PA were tested for ability to induce thioredoxin reductase and quinone reductase transcription in luciferase reporter gene constructs. PA did not activate transcription; ascorbic acid between 5 and 100uM resulted in significant, but relatively small induction. At Sf concentrations of 1 µM or less, purified Sf and broccoli extracts activated transcription equally well. These data suggest that Sf accounts for most of the ARE-activated transcriptional induction of antioxidant genes by broccoli. Further, Se enhancement alters production of potential bioactive compounds in broccoli, demonstrating the difficulty of maximizing all bioactive components in a single plant.