Inhibition of Lipid Peroxidation

His Methyl linoleate Imidazolelactic acid, Imidazoleacetic acid 

Cys Ethyl arachidonate Cystine, H2S, cysteic acid, alanine, cystine-disulfoxide 

Lys Methyl linoleate Diaminopentane, aspartic acid, glycine, alanine, a-aminoadipic acid, pipecolinic acid, 1,10-diamino-1,10-dicarboxydecane 

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Despite the fact that phloem is rich in catechins the amount of these ingested daily in our phloem study was rather small when compared to previously conducted studies. In similar studies the amount of catechins ingested in the form of tea or red wine per day has varied from 81 mg to as high as 2490 mg (de Rijke et al., 1996 Carbormeau et al., 1997 Nigdikar et al., 1998 Princen et al., 1998). It would be interesting to test in the future whether increasing the ingested amount of phloem would further reduce the inhibition of lipid peroxidation. 

SEERAM N P and NAIR M G (2002) Inhibition of lipid peroxidation and structure-activity-related studies of the dietary constituents autocyanins, autocyanidins, and catechins, JAgric Food Chem, 50, 5308-12. 

Younes, M., Mohr, A., Schoenberg, M.H. and Schildbeig, F.W. (1987). Inhibition of lipid peroxidation by superoxide dismutase following regional intestinal ischaemia and reperfiision. Res. Exp. Med. 187, 9-17. 

Steroids have long been used in the treatment of neurological injury. These highly lipophilic compounds have a high aflSnity for membrane bilayers. This property is key to their role in inhibition of lipid peroxidation. 

As mentioned earlier, when NO concentration exceeds that of superoxide, nitric oxide mostly exhibits an inhibitory effect on lipid peroxidation, reacting with lipid peroxyl radicals. These reactions are now well studied [42-44]. The simplest suggestion could be the participation of NO in termination reaction with peroxyl radicals. However, it was found that NO reacts with at least two radicals during inhibition of lipid peroxidation [50]. On these grounds it was proposed that LOONO, a product of the NO recombination with peroxyl radical LOO is rapidly decomposed to LO and N02 and the second NO reacts with LO to form nitroso ester of fatty acid (Reaction (7), Figure 25.1). Alkoxyl radical LO may be transformed into a nitro epoxy compound after rearrangement (Reaction (8)). In addition, LOONO may be hydrolyzed to form fatty acid hydroperoxide (Reaction (6)). Various nitrated lipids can also be formed in the reactions of peroxynitrite and other NO metabolites. 

Quercetin and rutin suppressed photosensitized hemolysis of human erythrocytes with ho values equal to 40 p.mol l-1 and 150 jjlmt>I I 1, respectively [139]. Suppression of photohemolysis was accompanied by inhibition of lipid peroxidation. Morin inhibited oxygen radical-mediated damage induced by superoxide or peroxyl radicals to the human cells in the cardiovascular system, erythrocytes, ventricular myocytes, and saphenous vein endothelial cells [140]. Rutin protected against hemoglobin oxidation inside erythrocytes stimulated by prooxidant primaquine [141],... 

Despite the conclusions in the cited literature about direct MT interaction with free radicals, the mechanism of MT antioxidant activity remains obscure. Markant and Pallauf [339] concluded that cysteine groups and not zinc are responsible for the inhibition of lipid peroxidation in hepatocytes. Maret and Vallee [340,341] also questioned the possibility of direct scavenging of free radicals by MT and suggested that zinc release is a major mechanism of antioxidant effects of metallothioneins. 

The inhibition of lipid peroxidation by metalloporphyrins apparently depends on metal ions because only compounds with transition metals were efficient inhibitors. Therefore, the most probable mechanism of inhibitory effects of metalloporphyrins should be their disuniting activity. Manganese metalloporphyrins seem to be more effective inhibitors than Trolox (/5o = 204 pmol I 1) and rutin (/50 112 pmol I 1), and practically equal to SOD (/50= 15 pmol I 1). The mechanism of inhibitory activity of manganese and zinc metalloporphyrins might be compared with that of copper- and iron-flavonoid complexes [167,168], which exhibited enhanced antiradical properties due to additional superoxide-dismuting activity. 

For the NO studies that show inhibition of lipid peroxidation, we used HL-60 cells made more oxidizable by adding 32 pM docosahexaenoic acid (22 6q)3 ) to the growth media. When unenriched cells were examined, inhibition of oxidation was qualitatively identical, but the magnitude of the effect was less, and therefore more difficult to measure. The effect of lipid unsaturation will be developed below. 

Dogterom P, Nagelkerke JF, van Steveninick J, et al. 1988. Inhibition of lipid peroxidation by disulfiram and diethydithiocarbamate does not prevent hepatotoxin-induced cell death in isolated rat hepatocytes. A study with allyl alcohol, tert-butyl hydroperoxide, diethyl maleate, bromoisovalerylurea and carbon tetrachloride. Chem Biol Interact 66 251-265. 

ZO037 Reddy, A. C., and B. R. Lokesh. Studies on spice principles as antioxidants in the inhibition of lipid peroxidation of rat liver microsomes. Mol Cell Biochem 1992 111(1-2) 117-124. 

Wiseman H, Cannon M, Arnstein HRV, Halliwell B. Mechanism of inhibition of lipid peroxidation by tamoxifen and 4-hydroxytamoxifen introduced into liposomes. Similarity to cholesterol... 

It is not known why the rat manunary gland is more responsive to CLA-mediated inhibition of lipid peroxidation than the liver, especially since CLA treated mouse liver microsomes exhibit inhibition of lipid peroxidation. Based on these observations it might be assumed that CLA affords different degrees of protection from oxidation in different tissues and sfpecies. In order to answer these questions, we are studying liver microsomes from rats and mice fed identical CLA-treated diets. 

Broussochalcone A (32) Antioxidant activity (inhibition of lipid peroxidation) Inhibition of cyclooxygenase Inhibition of nitric oxide production Inhibition of respiratory burst in neutrophils Platelet aggregation inhibitory activity1 [42] [431 [42] [44] [431... 

Broussoflavonol F (45) Antioxidant activity (inhibition of lipid peroxidation) Antiproliferative activity Inhibition of aromata eb Inhibition of cyclooxygenase Platelet aggregation inhibitory activity11 [45] [45] [41] [43] [43]... 

Protection of vascular endothelial cells from oxygen free radical damages Enhancement of SOD, catalase and peroxidase in the cytosol of kidney Protection of pulmonary endothelium against free radicals in rabbits Protection of lipid peroxidation in liver and cardiac muscle in rats Inhibition of lipid peroxidation of rat liver and brain microsomes Inhibition of lipid peroxidation in serum and liver in rats Protective effect of ginsenosides on reperfusion injuries... 

Chlorogenic and caffeic acids have suppressed the formation of hydroxyl radical via the Fenton reaction, probably due to chelation of these acids with iron [44], Indeed, recent studies report that chlorogenic acid shows chelating activity or reducing activity on iron required for the production of superoxide and hydroxyl radicals, resulting in the inhibition of lipid peroxidation induced Fenton reaction [45, 63],... 

In terms of human dietary requirements, much of the wheat for breadmaking in the United States is produced in selenium-adequate sections of the country. Bread is generally a good source of dietary selenium, Selenomethionine decomposes lipid peroxides and inhibits in vivo lipid peroxidation in tissues of vitamin-E-deficient chicks. Selenocysdne catalyzes the decomposition of organic hydroperoxides. Selenoproteins show a high degree of inhibition of lipid peroxidation in livers of sheep, chickens, and rats, Thus, some forms of selenium exhibit in vivo antioxidant behavior,... 

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