Elevation of quinone reductase activity by anticarcinogenic antioxidants

Presence of a heterozygous substitution and its relationship to DT-diaphorase activity

“…1994). This enzyme family is responsible for diverting potentially reactive electrophiles from damaging interactions with the nucleophilic groups of DNA and ultimately functions to protect tissue against carcinogenic and mutagenic compounds (Talalay and Benson, 1982). Twoelectron reduction bypasses the formation of the semiquinone, which in the presence of oxygen can be efficiently back-oxidised, leading to the production of active oxygen species (Lind et al.…”

Studies with 1,2-dithiole-3-thione as a chemoprotector of hydroquinone-induced toxicity to DBA/2-derived bone marrow stromal cells.

“…Extensive research since that time has demonstrated that induction of phase II enzymes as well as Significantly different from respective control by Student's t-test, p<0.05. glutathione is a useful strategy for enhancing the clearance and/or detoxification of chemically reactive intermediates (14,18,32). Quinone reductase (QR) has also been shown to be coordinately induced with other electrophile-processing phase II enzymes such as glutathione-S-transferases (14,17,18). Recently, the protection of hepatoma cells against the toxicity of a number of redox-active xenobiotics has been linked to the in vitro induction of QR (19).…”

“…Mechanistically, chemoprotection has been associated with the induction of three classes of detoxification enzymes: enzymes involved in ascorbic acid biosynthesis, the microsomal P450 class of enzymes, and soluble, cytosolic enzymes known collectively as phase II detoxification enzymes (17,31). Extensive research since that time has demonstrated that induction of phase II enzymes as well as Significantly different from respective control by Student's t-test, p<0.05. glutathione is a useful strategy for enhancing the clearance and/or detoxification of chemically reactive intermediates (14,18,32). Quinone reductase (QR) has also been shown to be coordinately induced with other electrophile-processing phase II enzymes such as glutathione-S-transferases (14,17,18).…”

“…""'*..e:---'X' ' 5 stromal element of the bone marrow (5 17-kD cytokine in purified murine bone marrow macrophages (10).~~~~~R ecently it was shown that quinone reductase (QR) activity and glutathione ...(GSH) concentration within stromal cells~~~r eimportant determinants of susceptibility to HQ-induced cytotoxicity (6,11,12 (13,14). In particular, QR catalyzes the two-electron reducof quinones to hydroquinones, which MF:~~~~~~~~~are then amenable to glucuronidation and excretion (15,16 (14,17,18). Recent studies bỹ…”

Electrophiles in Foods: The Current Status of Isothiocyanates and Their Chemical Biology

“…16) Subsequently, Talalay and his colleagues reported that administration of BHA to mice reduced the formation of mutagenic metabolites from benzo[a]pyrene and raised the activity levels of classical phase 2 detoxication enzymes such as GST in many tissues. 17) These observations led to the suggestion that the protective function of phenolic antioxidants, which can be metabolically converted into electrophiles, can be ascribed to the induction of the phase 2 response, that is electrophile counterattack responses. 18) In the following decades, the evidence supporting this suggestion became dramatically more convincing.…”