Oxidative stress antioxidant protection

Scapagnini G, Colombrita C, Amadio M, D Agata V, Arcelli E, Sapienza M, Quattrona A, Calabrese Y. 2006. Curcumin activates defensive genes and protects neurons against oxidative stress. Antioxid Redox Signal 8 395-403. 

Scapagnini G, Butterfield DA, Colombrita C, Sultana R, Pascale A, Calabrese V. 2004. Ethyl ferulate, a lipophilic polyphenol, induces HO-1 and protects rat neurons against oxidative stress. Antioxid Redox Signal 6 811-818. 

It has been proposed that the development of the complications of diabetes mellitus may be linked to oxidative stress and therefore might be attenuated by antioxidants such as vitamin E. Furthermore, it is discussed that glucose-induced vascular dysfunction in diabetes can be reduced by vitamin E treatment due to the inactivation of PKC. Cardiovascular complications are among the leading causes of death in diabetics. In addition, a postulated protective effect of vitamin E (antioxidants) on fasting plasma glucose in type 2 diabetic patients is also mentioned but could not be confirmed in a recently published triple-blind, placebo-controlled clinical trial [3]. To our knowledge, up to now no clinical intervention trials have tested directly whether vitamin E can ameliorate the complication of diabetes. 

Mincing, cooking and maturing expose meat products to oxidative stress for a long time so that antioxidants added for lipid protection are slowly destroyed on storage. Onion juice is a powerful antioxidant in meat products, more efficient than garlic juice. Lipid hydroperoxides are reduced to inactive hydroxyl derivatives by reaction with sulphur compounds present in those juices. 

The protective effects of carotenoids against chronic diseases appear to be correlated to their antioxidant capacities. Indeed, oxidative stress and reactive oxygen species (ROS) formation are at the basis of oxidative processes occurring in cardiovascular incidents, cancers, and ocular diseases. Carotenoids are then able to scavenge free radicals such as singlet molecular oxygen ( O2) and peroxyl radicals particularly, and protect cellular systems from oxidation. 

Betalains have shown strong antioxidant activities in biological environments such as membranes and LDLs," -" suggesting that the consumption of betalain-colored foods may exert protective effects against certain oxidative stress-related diseases (i.e., cancers) in humans. Beetroot has been used as a treatment for cancer in Europe for several centuries. The high content of betanin in red beetroot (300 to 600 mg/kg) may be the explanation for the purported cancer chemopreventive effects of beets. 

An extract from Lactuca indica showed significant free radical scavenging activity, and protected phixl74 supercoiled DNA against strand cleavage and reduced oxidative stress in human promyelocytic leukemia HL-60 cells. On account of protocatechulic acid, methyl p-hydroxybenzoate, caffeic acid, 3,5-dicaffeoylquinic acid, luteolin 7-O-fT glucopyranoside, and quercetin 3-0-(3-g 1 ucopyranoside are the major antioxidative constituents (111). 

Over the past years it has become apparent that the cell type is an important determinant of the extent of oxidative stress that may occur. Both the latent activities of cytoprotective enzymes in specific cell types, as well as the ability of the cell to respond rapidly to an oxidative insult by the upregulation of such enzymes, will be important predeterminants of the fate of the cell. Table 10.1 shows the concentrations of both antioxidants and cytoprotective enzymes in a variety of tissues. While the liver is well provided with antioxidant protection, the brain has very low levels, so the ability to respond rapidly to an oxidative insult by upregulation of gene transcription and translation will be an important determinant of survival or death. Cells such as hepatocytes have high levels of expression and... 

Phytochemicals or phytonutrients are bioactive substances that can be found in foods derived from plants and are not essential for life the human body is not able to produce them. Recently, some of their characteristics, mainly their antioxidant capacity, have given rise to research related to their protective properties on health and the mechanisms of action involved. Flavonoids are a diverse group of phenolic phytochemicals (Fig. 6.1) that are natural pigments. One function of flavonoids is to protect plants from oxidative stress, such as ultraviolet rays, environmental pollution, and chemical substances. Other relevant biological roles of these pigments are discussed in other chapters of this book. 

Aside from these two vitamins, uric acid has also been assigned an important role as antioxidant [29], It has the ability to protect vitamin C from oxidizing [30], Under strong oxidative stress, bilirubin also seems to be important [31, 32],... 

This mechanism is now considered to be of importance for the protection of LDL against oxidation stress, Chapter 25.) The antioxidant effect of ubiquinones on lipid peroxidation was first shown in 1980 [237]. In 1987 Solaini et al. [238] showed that the depletion of beef heart mitochondria from ubiquinone enhanced the iron adriamycin-initiated lipid peroxidation whereas the reincorporation of ubiquinone in mitochondria depressed lipid peroxidation. It was concluded that ubiquinone is able to protect mitochondria against the prooxidant effect of adriamycin. Inhibition of in vitro and in vivo liposomal, microsomal, and mitochondrial lipid peroxidation has also been shown in studies by Beyer [239] and Frei et al. [240]. Later on, it was suggested that ubihydroquinones inhibit lipid peroxidation only in cooperation with vitamin E [241]. However, simultaneous presence of ubihydroquinone and vitamin E apparently is not always necessary [242], although the synergistic interaction of these antioxidants may take place (see below). It has been shown that the enzymatic reduction of ubiquinones to ubihydroquinones is catalyzed by NADH-dependent plasma membrane reductase and NADPH-dependent cytosolic ubiquinone reductase [243,244]. 

In conclusion, it should be mentioned that there are numerous proposals for the application of various food products having antioxidant activity for the protection against various free radical-mediated pathologies. For example, it has been suggested that nutritional interventions such as increasing dietary intake of fruits and vegetables can decrease the age-related declines in brain functions probably via the suppression of oxidative stress [368],... 

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