Induction of Phase II enzymes

Isothiocyanates are potent inducers of Phase II detoxification enzymes, such as quinone reductase and glutathione transferase (Faulkner et al. 1998 Fahey and Talalay 1999 Rose et al. 2000 Basten et al. 2002 Munday and Munday 2004). The induction of these enzymes enables the excretion of potential carcinogens prior to harmftil effects and is thought to be an effective mechanism to reduce the risk of carcinogenesis. The mechanism by which this occurs is likely to be by the activation of the transcription factors Nrl2. Upon exposure to 

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There is ample evidence from both animal experiments and tissue cultures studies to show that brassica vegetables and their constituents selectively induce Phase II enzymes. Evidence for the induction of Phase II enzymes by... 

Induction of phase II enzymes, which conjugate reactive electrophiles and act as indirect antioxidants, appears to be the means for achieving protection against a variety of carcinogens in animals and humans. Transcriptional control of the expression of these enzymes is mediated, at least in part,... 

Similarly, it has been shown that consumption of cruciferous vegetables is associated with a lower incidence of cancers. Induction of phase II enzymes such as the glutathione S-transferase (GST) and quinone reductase (QR) have been demonstrated in broccoli, cabbage, and brussel sprouts. Many natural isothiocyanates derived from cruciferous vegetables and some fruits have been shown to cause induction of phase II enzymes in cultured cells and rodents. 

Tissues, mainly gastrointestinal and liver. Involved In uptake and metabolism of external carcinogens and mutagens, such as heterocyclic amines, provide a first barrier to damage, and Induction of phase II enzymes plays an elementary role In protecting against toxic compounds of low-molecular weight [84]. 

Stimulation of carcinogen detoxification through induction of phase II enzymes Induction of apoptosis or differentiation in the cancerous cells Induction of cell cycle arrest Iiihibition of angiogenesis, metastasis and invasion Iiihibition of tinnor promotion Iiihibition of tumor promotion... 

Stimulation of carcinogen detoxification through induction of phase II enzyme Inhibition of tumor promotion... 

Su BN. Gu JQ, Kang YH, Park EJ, Pezzuto JM, Kinghom AD (2004) Induction of phase II enzyme, quinone reductase, by withanoUdes and norwithanolides from solanaceous species. Mini-Rev Org Chem 1 115-123... 

We have studied on physiological, pharmaceutical or therapeutic effects of various edible plants, especially the sulfor-containing compounds from onion 15,16). Our continuous screening for the induction of GST activity in RL34 cells resulted in isolation of MS-ITC from the ethyl acetate (EtOAc) extract of wasabi. In this study, we describe the isolation of MS-ITC from wasabi, and examined the protein levels of GST isozyme induced by MS-ITC. As a result from elucidation of the intracellular redox state of BITC instead of MS-ITC, the isothiocyanate moiety of these food foctors phtys an important role for the induction of phase II enzymes. 

Yang, J. and Liu, R.H. 2009. Induction of phase II enzyme, quinone reductase, in murine hepatoma cells in vitro by grape extracts and selected phytochemicals. Food Chem., 224 898-904. 

The essential oil of many plants which are commonly consumed contain a wide variety of monoterpenes such as limonene and perillyl alcohol (Figure 4). These compounds have been shown to have a wide spectrum of anticancer activities (72). These compounds can detoxify carcinogen via the induction of phase II enzymes. 

Dinkova-Kostova, A.T., Holtzclaw, W.D., Cole, R.N. et al. (2002) Direct evidence that sulfhydryl groups of Kepi are the sensors regulating induction of Phase II enzymes that protect against carcinogens and oxidants. Proc. Natl. Acad. Set. USA, 99,11908-11913. 

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