Antioxidant enzyme induction

Some metabolites of curcumin (particularly tetrahydrocurcumin) may also participate in producing the observed effects of curcumin in different models because these metabolites display greater stabilities than the parent curcumin molecule at physiological pH. Recent data show similar modes of action of curcumin metabolites regarding antioxidant enzyme induction and inhibition of multidrug-resistant proteins. " Additional data indicate that curcumin may even act against other types of diseases such as atherosclerosis " " and Alzheimer s disease. " - " ... 

Table 14.4 Antioxidant enzyme induction and pro-inflammatory blockage...

The rice bran phytochemicals and antioxidants have a profound influence on the induction of antioxidant enzymes at the cellular level and control hpid peroxidation at the cellular level. 

It is possible that dietary flavonoids participate in the regulation of cellular function independent of their antioxidant properties. Other non-antioxidant direct effects reported include inhibition of prooxidant enzymes (xanthine oxidase, NAD(P)H oxidase, lipoxygenases), induction of antioxidant enzymes (superoxide dismutase, gluthathione peroxidase, glutathione S-transferase), and inhibition of redox-sensitive transcription factors. 

Induction For example, antioxidant enzymes, mitochondrial, membrane hyperpolarization, mitochondrial biogenesis... 

Shertzer HG, Sainsbury M. 1991. Chemoprotective and hepatic enzyme induction properties of indole and indenoindole antioxidants in rats. Food Chem Toxicol 29 391-400. 

Both in MCI and AD patients, mean plasma levels of nonenzymatic antioxidants and activity of antioxidant enzymes appeared to be lower than in controls, with no parallel induction of antioxidant enzymes (Keller et al., 2005). In order to explain these results it has been suggested that the increased free radical production in MCI might lead to a rapid consumption of plasma antioxidants without a simultaneous activation of new molecules of antioxidant enzymes. Individuals with MCI, and subsequently with AD, are likely to have an inadequate antioxidant enzymatic activity, unable to counteract the increased production of free radicals during the pathogenesis of the disease. 

Key Words Allium sativum, antilipemic platelet inhibition antioxidants cancer prevention P450 enzyme induction. 

Heat shock proteins is a family of proteins which were identified in relation to heat stress response and they are categorized on the basis of their approximate molecular weights. Heat shock protein induction is a rapid response to altered redox state and closely corresponds to the activity of antioxidant enzymes such as catalase. Heat shock proteins are induced in response to a number of stresses, including sublethal heal, hypoxia, reoxygenation and ischemia and reperfusion. 

Oltipraz [4-methyl-5-(2-pyrazinyl)-l, 2-dithiole-3-thione] (OPZ), a synthetic derivative of 1, 2-dithiole-3-thione, has been extensively investigated for its chemopreventive properties first developed as an antischistosomal agent, this compound was found to increase cellular thiol levels and to induce enzymes involved in the maintenance of reduced glutathione (GSH) pools and in detoxification of electrophilic intermediates. Induction of phase 2 enzymes such as GSTs, epoxide hydrolases, and NADP(H) quinone reductases was considered to represent the key mechanism of chemoprotection of OPZ. More recently this compound was also found to modulate phase 1 enzymes, antioxidant enzymes, and other inactivating proteins, thereby indicating that its chemoprevention mechanism(s) are more complex than first envisaged. In this chapter, current information about the effects of OPZ on phase 1 and phase 2 enzymes is presented. 

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