Ascorbic acid vitamin E and

Shukla A, Rasik A, Patnaik M (1997) Depletion of reduced glutathione, ascorbic acid, vitamin E and antioxidant defense enzymes in healing cutaneous wounds. Free Radic Res 26(2) 93-101... 

Peroxynitrite is a very reactive species capable of reacting with many biomolecules including the antioxidants ascorbic acid, vitamin E, and uric acid [97-99], thiols [100], DNA [101], phospholipids [102], etc (see later). Because of this, a great interest has been drawn to the mechanisms of peroxynitrite reactions. 

Diced turkey bologna was dipped in water (none) or different antioxidants solutions before irradiated at 3 kGy. The antioxidants tested were 20 mM of ascorbic acid, vitamin E, and sesamol, or 0.75% of rosemary extract (rosemary). Volatile compounds were measured the next day, and expressed as square root of peak area count. The numbers were means of four replicates... 

FIA methods based on ferric reducing power similar to the FRAP principle reaction have been used for the determination of ascorbic acid, vitamin E, and total iron. Table 30.1 summarizes most of these studies. Spectrophotometric detection is also used in many of these studies because of the chromogenic effect from Fe oxidation, which changes with complex ligands, such as TPTZ, o-phenanthroline, cyanide, and DPPH. Different FIA manifolds have also been investigated and proposed, from single to multiple lines. Therefore, like other chromogenic antioxidant tests, the FRAP assay has the potential for several flow injection adaptations. 

Finally, metabolism and inactivation of Cd-induced ROS by cells and tissues can also be perceived as indirect processes that contribute to Cd detoxification. The cellular antioxidative defense mechanisms responsible for ROS scavenging have been thoroughly reviewed [474,489]. They include antioxidative enzymes (e.g., superoxide dismutases, catalases, glutathione peroxidases, antioxidative metabolites (GSH, ascorbic acid, vitamin E) and the enzymes involved in their regeneration (thioredioxins, glutaredoxins, glutathione reductases). 

Eberlein-Konig B, Placzek M, Pryzbilla B (1998) Protective effect against sunburn of combined systemic ascorbic acid (vitamin C) and d-alpha-tocopherol (vitamin E). J Am Acad Dermatol 38 45-48... 

Cyanobacteria and algae have evolved a complex defense system against ROS, including non-enzymatic antioxidants like carotenoids, tocopherols (vitamin E), ascorbic acid (vitamin C) and reduced glutathione (Asada 1994). 

Fumed silica A-200 (Pilot plant at the Institute of Surface Chemistry, Kalush, Ukraine specific surface area Ascorbic acid (vitamin C) and all-rac-a-Tocopheryl acetate (vitamin E acetate) were used as adsorbates. Folin-Ciocalteu s phenol reagent (Merck) was used to measure the total polyphenolic index. Silica samples with different degree of surface silylation were obtained using gas-phase chemical modification of highly disperse silica (A-200) surface by trimethylchlorosilane.6... 

The processes that cause oxidation of LDL involve superoxide radicals, nitric oxide, hydrogen peroxide, and other oxidants (see Chapter 24). Antioxidants, such as vitamin E, ascorbic acid (vitamin C), and carotenoids, may be involved in protecting LDL from oxidation. 

Recent studies in biological systems have revealed the presence of a variety of compounds of many structural types that appear to function as antioxidants. The plant kingdom is especially rich in these materials (Larson, 1988). They include flavonoids and other phenolic compounds, alkaloids and other amines, reduced sulfur compounds, uric acid, ascorbic acid. Vitamin E, carotenoids, and many other substances. Often, their principal mechanism of action appears to be the quenching of peroxy radicals, removing them from the autooxidation chain. Vitamin E, for example, reacts with these radicals in a manner entirely analogous to that of BHT ... 

Tomato (Solarium lycopersicwn L.) is extensively cultivated worldwide, and its fruits have assumed the status of functional foods as a result of epidemiological evidence of reduced risks of certain types of cancers and cardiovascular diseases [180,181]. They are a reservoir of diverse antioxidant molecules, such as lycopene, ascorbic acid, vitamin E, carotenoids, flavraioids, and phenolics, and may provide a significant part of the total intake of beneficial phytochemicals, as a result of then-high consumption rates. Among carotenoids, lycopene has a strong antioxidant activity and is able to induce cell-to-ceU communications and modulate hormones, immune systems, and other metabolic pathways [182]. 

The ascorbic acid-vitamin E interaction is also important to maintain the protease-antiprotease balance in the lung. Ascorbic acid reacts with glutathione, and through antioxidant synergism it can increase the effectiveness of vitamin E. The following series of enzymatic reduction reactions that occur in the cells illustrates the participation of ascorbic acid in the inhibition of lipid peroxidation. 

Antioxidants are chemical compoimds that can bind to free radicals and thus prevent them from damaging healthy cells. Antioxidants can be divided into enzymatic and non-enzymatic subtypes. Several antioxidant enzymes are produced by the body, with the three major classes being catalase, the glutathione (GSH) peroxidases, and the superoxide dismutases (SODs). Non-enzymatic antioxidants include the irmate com-poimd glutathione as well as antioxidant vitamins obtained through the diet, such as a-tocopherol (vitamin E), ascorbic acid (vitamin C), and P-carotene. 

Thus, it is uncertain to what extent the apparent protective effects of fruit and vegetable consumption on risk of stomach cancer can be attributable to their phytoestrogen content. This appears not to have been studied directly, and other constituents such as ascorbic acid (vitamin C), a-tocopherol (vitamin E) and /1-carotene may be potentially protective. 

Commercial green tea leaves contain ascorbic acid (vitamin C) about 280 mg per 100 g dried leaves. Vitamin E in tea leaves is around 24-80 mg/lOOg dry weight but, because of its lipophilicity, solubility is low in tea infusions. The content of B vitamins in tea is around 8-15 mg/lOOg (Cheng and Chen 1994). 

Nonaqueous Systems In nonaqueous (nonpolar) solvent systems, nitrosatlon also proceeds. In these solvents, alpha-tocopherol acts as a lipid soluble blocking agent in much the same fashion as ascorbic acid functions in the aqueous phase. Alpha-tocopherol reacts with a nitrosating agent and reduces it to nitric oxide. At the same time, alpha-tocopherol is oxidized to tocoquinone, which is the first oxidation product of vitamin E and also a normal metabolite in vivo. 

Well-characterized transition metal complexes of vitamin C (ascorbic acid) are rare, and a select number of these exhibit anticancer properties. Hollis et al. have described the first examples to be fully characterized by X-ray crystallography.316 Treatment of [Pt(H20)2L2]2+ (L = NH3, MeNH2 L2 = en, 1,2-chxn) with ascorbic acid gives either the mono- or bisascorbate species of the type cis-[PtL2(C2,Os-ascorbate)] (e.g., (125)) or m-[PtL2(C2-ascorbate)(03-ascorbate)], respectively. Interestingly, in both types of complexes, platinum(II) forms a bond with the C-2 atom of ascorbic... 

The results of the lymphocyte experiments with N02 and ONOO- are given in Tables 14.4 and 14.5. The major finding is that cells that are treated with the (3-CAR in addition to vitamins E and C in vivo and exposed to N02 show the cell staining of 6.0% whereas, without the antioxidants, the cell staining was 61.4%. That is, the presence of all three of the antioxidants leads to a protection factor (PF) of 10.2. the protection by (3-CAR alone gave a PF of only 2.0, for a-tocopherol alone it was 1.8 and for ascorbic acid 1.2. 

The synergistic effect observed in the presence of all three antioxidants implies that there is an interaction between the individual antioxidant components. The direct interaction of the a-tocopherol radical and ascorbic acid is already well established (Bisby and Parker 1995) and a study by Mayne and Parker (1989) on chicks deficient in vitamin E and selenium showed that the... 

The best known and undoubtedly most important natural antioxidants are a-tocopherol (vitamin E) and ascorbic acid (vitamin C), which are major biological antioxidants in lipid... 

The possible involvement of free radicals in the development of hypertension has been suspected for a long time. In 1988, Salonen et al. [73] demonstrated the marked elevation of blood pressure for persons with the lowest levels of plasma ascorbic acid and serum selenium concentrations. In subsequent studies these authors confirmed their first observations and showed that the supplementation with antioxidant combination of ascorbic acid, selenium, vitamin E, and carotene resulted in a significant decrease in diastonic blood pressure [74] and enhanced the resistance of atherogenic lipoproteins in human plasma to oxidative stress [75]. Kristal et al. [76] demonstrated that hypertention is accompanied by priming of PMNs although the enhancement of superoxide release was not correlated with the levels of blood pressure. Russo et al. [77] showed that essential hypertension patients are characterized by higher MDA levels and decreased SOD activities. 

Small-molecule antioxidants include glutathione, ascorbic acid (vitamin C), vitamin E and a number of dietary flavonoids. Because humans, in contrast to most other animals, are unable to synthesize vitamin C, this important antioxidant must be supplied entirely from dietary intake. Other proteins, such as thioredoxin and metallothionein, may also contribute to some extent to the cellular antioxidant pool. 

Chromium compounds interact synergistically or antagonistically with many chemicals. For example, potassium dichromate administered by subcutaneous injection potentiated the effects of mercuric chloride, citrinin, and hexachloro-1,3-butadiene on rat kidneys (USPHS 1993). Chromium effects were lessened by ascorbic acid and Vitamin E, and N-acetyl cysteine was effective in increasing urinary excretion of chromium in rats (USPHS 1993)... 

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