Chlorophyll, chlorophyllin and related tetrapyrroles are significant inducers of mammalian phase 2 cytoprotective genes.

  title={Chlorophyll, chlorophyllin and related tetrapyrroles are significant inducers of mammalian phase 2 cytoprotective genes.},
  author={Jed W. Fahey and Katherine K. Stephenson and Albena T. Dinkova-Kostova and Patricia A. Egner and Thomas W. Kensler and P. G. Talalay},
  volume={26 7},
Plant chlorophylls and carotenoids are highly colored, conjugated polyenes that play central roles in photosynthesis. Other porphyrins (tetrapyrroles), such as cytochromes, which are structurally related to chlorophyll, participate in redox reactions in many living systems. An unexpected new property of tetrapyrroles, including tetramethyl coproporphyrin III, tetrabenzoporphine, copper chlorin e4 ethyl ester, and of carotenoids including zeaxanthin and alpha-cryptoxanthin is their ability to… 

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Broccoli sprouts: an exceptionally rich source of inducers of enzymes that protect against chemical carcinogens.
  • J. Fahey, Y. Zhang, P. Talalay
  • Chemistry, Medicine
    Proceedings of the National Academy of Sciences of the United States of America
  • 1997
Induction of phase 2 detoxication enzymes [e.g., glutathione transferases, epoxide hydrolase, NAD(P)H: quinone reductase, and glucuronosyltransferases] is a powerful strategy for achieving protection
Direct evidence that sulfhydryl groups of Keap1 are the sensors regulating induction of phase 2 enzymes that protect against carcinogens and oxidants
This finding suggests that reaction of cysteine thiols is followed by rapid formation of protein disulfide linkages, which are the direct sensors of inducers of the phase 2 system.
Total intracellular accumulation levels of dietary isothiocyanates determine their activity in elevation of cellular glutathione and induction of Phase 2 detoxification enzymes.
Results showed that cellular accumulation levels of ITCs determine their activity in inducing cellular detoxification capacity and suggested that the intracellular AUC might be a valuable biomarker of the Phase 2 enzyme inducer activity of I TCs.
Non-specific inhibition of cytochrome P450 activities by chlorophyllin in human and rat liver microsomes.
Comparison of the apparent Ki for P450 inactivation with previously estimated constants for chlorophyllin-IQ complexation suggest that P450 inhibition should be the dominant mechanism of inhibition.
Potency of Michael reaction acceptors as inducers of enzymes that protect against carcinogenesis depends on their reactivity with sulfhydryl groups
Proton NMR spectroscopy provides no evidence for increased electrophilicity of the β-vinyl carbons (the presumed site of nucleophilic attack) on the hydroxylated inducers, and ortho-hydroxyl groups display a propensity for extensive intermolecular hydrogen bond formation, which may raise the reactivity and facilitate addition of mercaptans, thereby raising inducer potencies.