Antioxidative protection

As has already been stated, the carotenoids are lipophilic and are therefore absorbed and transported in association with the lipoprotein particles. In theory, this fortuitous juxtaposition of lipid and carotenoid should confer protection on the lipid through the antioxidant properties of the carotenoid. No doubt some antioxidant protection is afforded by the presence of the carotenoids derived from the diet. However, with one or two exceptions, human supplementation studies have not supported a role for higher dose carotenoid supplements in reducing the susceptibility of the low-density lipoproteins to oxidation, either ex vivo or in vivo (Wright et al, 2002 Hininger et al, 2001 Iwamoto et al, 2000). 

The antioxidant property of ferulic acid and related compounds from rice bran was reported by Kikuzaki et al, (2002). Their results indicated that these compounds elicit their antioxidant function through radical scavenging activity and their affinity with lipid substrates. Another recent study reported by Butterfield et al, (2002) demonstrated that ferulic acid offers antioxidant protection against hydroxyl and peroxyl radical oxidation in synaptosomal and neuronal cell culture systems in vitro. The effect of ferulic acid on blood pressure (BP) was investigated in spontaneously hypertensive rats (SHR). After oral administration of ferulic acid the systolic blood pressure (SBP) decreased in a dose-dependent manner. There was a significant correlation between plasma ferulic acid and changes in the SBP of the tail artery, suggesting... 

BUTTERFIELD D A, MARINA A, JAROSLAW K, ANTONIO s (2002) FeruUc add antioxidant protection against hydroxyl and peroxyl radical oxidation in synaptosomal and neuronal cell culture systems in vitro Structure activity studies. JNutri Biochem, 13(5) 273-81. 

Cross, C.E., Halliwell, B. and Allen, A. (1984). Antioxidant protection a function of tracheobronchial and gastrointestinal mucus. Lancet i, 1328-1330. 

Albee, W.E., Jacobs, J., Phillips, M.L., Fischer, L., Panetta, J.A. and Gidda, J.S. (1991). LY213829 an antioxidant protects against acetic acid induced colitis in rats. Gastroenterology 100, A556. 

B47. Brigham, K. L Meyrick, B., Berry, L. C Jr., and Repine, J. E., Antioxidants protect cultured bovine lung endothelial cells from injury by endotoxin. J. Appl. Physiol. 63, 840-850 (1987). 

Moreover, carotenoids themselves are very susceptible to oxidative damage and their oxidation products include deleterious aldehydes (Failloux et al., 2003 Hurst et al., 2005 Rozanowski and Rozanowska, 2005 Siems et al., 2000, 2002 Sommerburg et al., 2003). Therefore it is of interest to find out how carotenoids can offer antioxidant protection in cellular systems, how stable the carotenoids are within cells, and what the fate of the carotenoid degradation products is. 

Altogether, studies in cultured RPE indicate that lutein and zeaxanthin may provide antioxidant protection in the RPE but more research is required to determine the exact mechanisms responsible for the observed protective effects or the lack thereof. 

Horak, P, Zilmer, M, Saks, L, Ots, I, Kara, U, and Zilmer, K, 2006. Antioxidant protection, carotenoids and the costs of immune challenge in greenfinches. J Exp Biol 209,4329-4338. 

Riso, P, F Visioli, D Erba, G Testolin, and M Porrini. 2004. Lycopene and vitamin C concentrations increase in plasma and lymphocytes after tomato intake. Effects on cellular antioxidant protection. Eur J Clin Nutr 58 1350-1358. 

Imam, S.Z., Newport, G.D., Islam, F., Slikker, W.J., Ali, S.F. Selenium, an antioxidant, protects against methamphetamine-induced dopaminergic neurotoxicity. Brain Res. 18 575, 1999. 

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... 

Dithiocarbamates are polar in nature and thus will have a tendency to bloom when used in nonpolar rubbers. The worst bloom problems will be encountered with the dimethyl derivatives higher alkyl chain types have better solubility in non-polar rubbers. Some dithiocarbamates also confer antioxidant protection. 

Antioxidative protection mechanisms can be classified into at least four categories [2], i.e., compartmentation, detoxification, repair, and utilization the first two have a direct relationship to antioxidizability. 

Table 2 Antiradical Activity of Red and White Wines (ACWw) and Their Antioxidative Protective Effectiveness in the Test System of the Cu2+-Initiated LDL Oxidation...

Ardelt BK, Borowitz JL, Isom GE. 1989. Brain lipid peroxidation and antioxidant protectant mechanisms following acute cyanide intoxication. Toxicology 56 147-154. 

Selenium is a significant component of the enzymatic system of the glutafion for antioxidant protection. It is included in the composition of 200 enzymes engaged in different biochemical reactions, demonstrates the immune-tropic, antiteratogenic and anticancer properties, betters the functional state of muscles, especially myocarditis, and takes part in hormones synthesis of the thyroid gland. Selenium s deficit in soil is the cause of hearth deficiency in endemic zones. 

Oz,H.S. etal. (2004) Diverse antioxidants protect against acetaminophen hepatotoxicity. Journal of Biochemical and Molecular Toxicology, 18 (6), 361-368. 

Friel, J. K., Martin, S. M., Langdon, M., Herzberg, G. R., and Buettner, G. R. (2002). Milk from mothers of both premature and full-term infants provides better antioxidant protection than does infant formula. Pediutr. Res. 51, 612-618. 

Some tissues obviously are able to accumulate micronutrients selectively and to use them predominantly for specific functions. It has, for instance, been known for a long time that the accumulation of p-carotene in the skin does not only provide a golden-yellow color but considerable antioxidative protection as well. Yet... 

Meng QH, Hockerstedt A, Heinonen S et al. Antioxidant protection of lipoproteins containing estrogens in vitro evidence for low- and high-density lipoproteins as estrogen carriers. Biochim. Biophys. Acta 1439, 331-340, 1999. 

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