Tocopherols, Carotenoids and The Glutathione System

Sies, Helmut; Murphy, Michael E.; Mascio, Paolo Di; Stahl, Wilhelm

doi:10.1007/978-3-0348-7432-8_14

Cited by 10 publications

(6 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By far, the most extensive and clinically applicable research on dietary factors in carcinogenesis relates to vitamin A, p-carotene, and vitamin C. The underlying biochemical mechanisms are unknown, but there is evidence for a role of the antioxidative capacity of p-carotene and vitamin C (1,2).…”

Section: Introductionmentioning

confidence: 99%

Serum carotene, vitamin A, and vitamin C levels in breast cancer and cancer of the uterine cervix

Ramaswamy

Krishnamoorthy

1996

Nutrition and Cancer

View full text Add to dashboard Cite

Levels of carotene, vitamin A, and vitamin C measured in the serum of patients with cancer of the breast and uterine cervix were compared with levels in healthy controls and patients with benign diseases of the breast and cervix. Serum ascorbate levels were significantly lower in patients with benign diseases of the breast and cervix than in controls. In cancer patients, there was a significant trend of lower serum vitamin levels with increasing stage of the disease.

show abstract

Section: Introductionmentioning

confidence: 99%

Serum carotene, vitamin A, and vitamin C levels in breast cancer and cancer of the uterine cervix

Ramaswamy

Krishnamoorthy

1996

Nutrition and Cancer

View full text Add to dashboard Cite

show abstract

“…In the circulation, tocopherol can be exchanged between all types of lipoproteins without passing through the liver [21]. ·-Tocopherol is the most important chain-breaking antioxidant present in human membranes [30,75]. It reacts with an organic peroxyl radical to form the corresponding organic hydroperoxide and the tocopheryl radical.…”

Section: Introductionmentioning

confidence: 99%

“…Vitamin E protects against atherosclerosis and cancerogenesis, and decreases mortality from cardiac ischemia. High concentrations of vitamin E may have prooxidative activity [16,28,30,63,75].…”

Section: Introductionmentioning

confidence: 99%

Oxidative Stress, Metabolism of Ethanol and Alcohol-Related Diseases

Zima

Fialová

Mestek

et al. 2001

Journal of Biomedical Science

View full text Add to dashboard Cite

Alcohol-induced oxidative stress is linked to the metabolism of ethanol. Three metabolic pathways of ethanol have been described in the human body so far. They involve the following enzymes: alcohol dehydrogenase, microsomal ethanol oxidation system (MEOS) and catalase. Each of these pathways could produce free radicals which affect the antioxidant system. Ethanol per se, hyperlactacidemia and elevated NADH increase xanthine oxidase activity, which results in the production of superoxide. Lipid peroxidation and superoxide production correlate with the amount of cytochrome P450 2E1. MEOS aggravates the oxidative stress directly as well as indirectly by impairing the defense systems. Hydroxyethyl radicals are probably involved in the alkylation of hepatic proteins. Nitric oxide (NO) is one of the key factors contributing to the vessel wall homeostasis, an important mediator of the vascular tone and neuronal transduction, and has cytotoxic effects. Stable metabolites – nitrites and nitrates – were increased in alcoholics (34.3 ± 2.6 vs. 22.7 ± 1.2 µmol/l, p < 0.001). High NO concentration could be discussed for its excitotoxicity and may be linked to cytotoxicity in neurons, glia and myelin. Formation of NO has been linked to an increased preference for and tolerance to alcohol in recent studies. Increased NO biosynthesis also via inducible NO synthase (NOS, chronic stimulation) may contribute to platelet and endothelial dysfunctions. Comparison of chronically ethanol-fed rats and controls demonstrates that exposure to ethanol causes a decrease in NADPH diaphorase activity (neuronal NOS) in neurons and fibers of the cerebellar cortex and superior colliculus (stratum griseum superficiale and intermedium) in rats. These changes in the highly organized structure contribute to the motor disturbances, which are associated with alcohol abuse. Antiphospholipid antibodies (APA) in alcoholic patients seem to reflect membrane lesions, impairment of immunological reactivity, liver disease progression, and they correlate significantly with the disease severity. The low-density lipoprotein (LDL) oxidation is supposed to be one of the most important pathogenic mechanisms of atherogenesis, and antibodies against oxidized LDL (oxLDL) are some kind of epiphenomenon of this process. We studied IgG oxLDL and four APA (anticardiolipin, antiphosphatidylserine, antiphosphatidylethanolamine and antiphosphatidylcholine antibodies). The IgG oxLDL (406.4 ± 52.5 vs. 499.9 ± 52.5 mU/ml) was not affected in alcoholic patients, but oxLDL was higher (71.6 ± 4.1 vs. 44.2 ± 2.7 µmol/l, p < 0.001). The prevalence of studied APA in alcoholics with mildly affected liver function was higher than in controls, but not significantly. On the contrary, changes of autoantibodies to IgG oxLDL revealed a wide range of IgG oxLDL titers in a healthy population. These parameters do not appear to be very promising for the evaluation of the risk of atherosclerosis. Free radicals increase the oxidative modification of LDL. This is one of the most important mechanism...

show abstract

“…Aliphatic thiol structures are commonly considered to be antioxidants, which are also active under biological conditions, i.e., within living cells. Gluthathione, for example, is well-known as a regulating and repairing antioxidant . In the course of the reaction cycle of gluthathione with ascorbate, the intermediate thiyl radicals are considered to be harmless in that they do not undergo further transformations or induce any damage.…”

Section: Resultsmentioning

confidence: 99%

Reactivity and Selectivity of Reactions of Small Radicals with a Multifunctional Heterocyclic Molecule: 3-(Mercaptoethyl)chinazoline-2,4-(1H,3H)dione

et al. 2000

View full text Add to dashboard Cite

Using pulse radiolysis, we studied the reactions of small radicals (e- aq, OH • , N3 • , and • CH2OH) with 3-(mercaptoethyl)chinazoline-2,4-(1H,3H)dione in aqueous solution. Whereas the solvated electron adds selectively to the carbonyl group near the aromatic moiety, the hydroxyl radical reacts by addition to the aromatic ring as well as by H abstraction at >N(1)H and −SH groups. Also, azide radicals nonspecifically oxidize the aromatic ring, the thiol group, or the thiolate anion and the amine group at N(1), as identified by subsequent radical products. In contrast, hydroxymethyl radicals (derived from methanol) abstract hydrogen selectively at the thiol group. The thiyl radical formed was used to study the kinetics of H abstraction in the bisallylic positions of linolenic acid. Product transient identification was performed by kinetic analysis as well as by comparison with reactions of molecules with structures less complex than that of the title compound, exhibiting relevant functional groups.

show abstract

Tocopherols, Carotenoids and The Glutathione System

Cited by 10 publications

References 32 publications

Serum carotene, vitamin A, and vitamin C levels in breast cancer and cancer of the uterine cervix

Serum carotene, vitamin A, and vitamin C levels in breast cancer and cancer of the uterine cervix

Oxidative Stress, Metabolism of Ethanol and Alcohol-Related Diseases

Reactivity and Selectivity of Reactions of Small Radicals with a Multifunctional Heterocyclic Molecule: 3-(Mercaptoethyl)chinazoline-2,4-(1H,3H)dione

Contact Info

Product

Resources

About