Transcription factor Nrf2 is essential for induction of NAD(P)H:quinone oxidoreductase 1, glutathione S-transferases, and glutamate cysteine ligase by broccoli seeds and isothiocyanates

J Nutr. 2004 Dec;134(12 Suppl):3499S-3506S. doi: 10.1093/jn/134.12.3499S.


Cruciferous vegetables contain glucosinolates that, after conversion to isothiocyanates (ITC), are capable of inducing cytoprotective genes. We examined whether broccoli seeds can elicit a chemoprotective response in mouse organs and rodent cell lines and investigated whether this response requires nuclear factor-erythroid 2 p45-related factor 2 (Nrf2). The seeds studied contained glucosinolate at 40 mmol/kg, of which 59% comprised glucoiberin, 19% sinigrin, 8% glucoraphanin, and 7% progoitrin. Dietary administration of broccoli seeds to nrf2(+/+) and nrf2(-/-) mice produced a approximately 1.5-fold increase in NAD(P)H:quinone oxidoreductase 1 (NQO1) and glutathione S-transferase (GST) activities in stomach, small intestine, and liver of wild-type mice but not in mutant mice; increased transferase activity was associated with elevated levels of GSTA1/2, GSTA3, and GSTM1/2 subunits. These seeds also increased significantly the level of glutamate cysteine ligase catalytic (GCLC) subunit in the stomach and the small intestine of nrf2(+/+) mice but not nrf2(-/-) mice. An aqueous broccoli seed extract was prepared for treatment of cultured cells that contained ITC at approximately 600 mumol/L, composed of 61% 3-methylsulfinylpropyl ITC, 30% sulforaphane, 4% allyl ITC, and 4% 3-butenyl ITC. This extract induced GSTA1/2, GSTA3, NQO1, and GCLC between 3-fold and 10-fold in mouse Hepa-1c1c7 and rat liver RL-34 cells. The broccoli seed extract affected increases in GSTA3, GSTM1, and NQO1 proteins in nrf2(+/+) mouse embryonic fibroblasts but not in nrf2(-/-) mouse embryonic fibroblasts. These experiments show that broccoli seeds are effective at inducing antioxidant and detoxication proteins, both in vivo and ex vivo, in an Nrf2-dependent manner.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brassica / chemistry*
  • Cell Line
  • DNA-Binding Proteins / deficiency
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology*
  • Diet
  • Enzyme Induction / drug effects
  • Gene Expression / drug effects
  • Glucosinolates / analysis
  • Glucosinolates / metabolism
  • Glutamate-Cysteine Ligase / biosynthesis*
  • Glutathione Transferase / biosynthesis*
  • Intestine, Small / enzymology
  • Isothiocyanates / administration & dosage
  • Isothiocyanates / analysis
  • Isothiocyanates / pharmacology*
  • Liver / enzymology
  • Mice
  • Mice, Knockout
  • Mutation
  • NAD(P)H Dehydrogenase (Quinone) / biosynthesis*
  • NF-E2-Related Factor 2
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology
  • Seeds / chemistry
  • Stomach / enzymology
  • Trans-Activators / deficiency
  • Trans-Activators / genetics
  • Trans-Activators / physiology*
  • Transfection


  • DNA-Binding Proteins
  • Glucosinolates
  • Isothiocyanates
  • NF-E2-Related Factor 2
  • Nfe2l2 protein, mouse
  • Plant Extracts
  • Trans-Activators
  • NAD(P)H Dehydrogenase (Quinone)
  • NQO1 protein, human
  • Glutathione Transferase
  • Glutamate-Cysteine Ligase