Interest in nutrition and food consumption in advanced countries has become an important instrument of active care for maintaining the population's health. Basic orientation in food composition and in topical knowledge about the effectiveness of individual nutrients in the human organism form an indispensable part of nutrition and health consciousness and it can significantly facilitate and improve activity in both professionals and non-professionals, or it can correct some subjective opinions and deep-rooted imaginations. At the end of the last century progress in molecular biological research led to better knowledge about previously unknown functions of nutrients in the metabolism and also knowledge about relationships among the individual nutrients. The interest of research institutes was concentrated on selected nutrient groups and also on vitamins. Attention was focused on verification of the role of vitamin E and beta carotene in strengthening the antioxidative capacity of the organism and immunity system as prevention against degenerative diseases, atherosclerosis and tumorous diseases. Attention was attracted to the fact that folacin acts preventively against defects of the neural tube and against hyperhomocysteinemia as an independent atherosclerosis risk factor. Also the data about the organism's needs, for example vitamins, are mostly not quite complete, especially in the sphere of detailed knowledge of their preventive effect concerning the so-called civilization diseases, their use in the organism and the reaction of the organism to their insufficient or redundant supply.

• MeSH
• antioxidancia farmakologie   MeSH
• fyziologie výživy * MeSH
• lidé MeSH
• vitaminy farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• antioxidancia MeSH
• vitaminy MeSH

The following extraction techniques have been used for extracting antioxidants (apigenin, coumarin, esculetin, umbelliferone, bergapten, quercetin, rutin, scopoletin and xanthotoxin) from plant material: supercritical fluid extraction, pressurized liquid extraction, extraction by means of Soxhlet apparatus, ultrasonic extraction in ultrasonic bath, and by means of ultrasonic probe. The analytical method based on HPLC-UV detection for the determination of selected antioxidants was developed. For all extracts the antioxidant capacity based on the reduction of free 2,2-diphenyl-1-picrylhydrazyl radical was also determined. Comparing all results the ultrasonic probe method using 0.75 g of sample extracted by 50 mL of acetonitrile in water (30%, v/v) for 25 min at room temperature and with amplitude at 60% (equal to 90 W) without pulsation was evaluated as the best tool. The most significant indicator demonstrating this statement is the antioxidant capacity expressed as gallic acid equivalent where the ultrasonic probe method showed the best results in 10 of 16 samples. Also the operability of ultrasonic probe extraction method compared to other tested methods is more favorable.

• Klíčová slova
• Antioxidant capacity, Antioxidants, Extraction methods, HPLC−UV, Plants,
• MeSH
• antioxidancia analýza   MeSH
• listy rostlin chemie   MeSH
• rostlinné extrakty analýza   MeSH
• rostliny chemie   MeSH
• spektrofotometrie ultrafialová MeSH
• superkritická fluidní chromatografie * MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• antioxidancia MeSH
• rostlinné extrakty MeSH

Tocochromanols (tocopherols, tocotrienols and plastochromanol-8), isoprenoid quinone (plastoquinone-9 and plastoquinol-9) and carotenoids (carotenes and xanthophylls), are lipid-soluble antioxidants in the chloroplasts, which play an important defensive role against photooxidative stress in plants. In this study, the interplay between the antioxidant activities of those compounds in excess light stress was analyzed in wild-type (WT) Arabidopsis thaliana and in a tocopherol cyclase mutant (vte1), a homogentisate phytyl transferase mutant (vte2) and a tocopherol cyclase overexpressor (VTE1oex). The results reveal a strategy of cooperation and replacement between α-tocopherol, plastochromanol-8, plastoquinone-9/plastoquinol-9 and zeaxanthin. In the first line of defense (non-radical mechanism), singlet oxygen is either physically or chemically quenched by α-tocopherol; however, when α-tocopherol is consumed, zeaxanthin and plastoquinone-9/plastoquinol-9 can provide alternative protection against singlet oxygen toxicity by functional replacement of α-tocopherol either by zeaxanthin for the physical quenching or by plastoquinone-9/plastoquinol-9 for the chemical quenching. When singlet oxygen escapes this first line of defense, it oxidizes lipids and forms lipid hydroperoxides, which are oxidized to lipid peroxyl radicals by ferric iron. In the second line of defense (radical mechanism), lipid peroxyl radicals are scavenged by α-tocopherol. After its consumption, plastochromanol-8 overtakes this function. We provide a comprehensive description of the reaction pathways underlying the non-radical and radical antioxidant activities of α-tocopherol, carotenoids, plastoquinone-9/plastoquinol-9 and plastochromanol-8. The interplay between the different plastid lipid-soluble antioxidants in the non-radical and the radical mechanism provides step by step insights into protection against photooxidative stress in higher plants.

• Klíčová slova
• Antioxidants, Arabidopsis thaliana, Lipid peroxidation, Photooxidative stress, Plastoquinone-9, Singlet oxygen, Tocochromanols,
• MeSH
• antioxidancia MeSH
• Arabidopsis * genetika   MeSH
• chloroplasty MeSH
• světlo MeSH
• tokoferoly MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antioxidancia MeSH
• tokoferoly MeSH

A physiological level of oxygen/nitrogen free radicals and non-radical reactive species (collectively known as ROS/RNS) is termed oxidative eustress or "good stress" and is characterized by low to mild levels of oxidants involved in the regulation of various biochemical transformations such as carboxylation, hydroxylation, peroxidation, or modulation of signal transduction pathways such as Nuclear factor-κB (NF-κB), Mitogen-activated protein kinase (MAPK) cascade, phosphoinositide-3-kinase, nuclear factor erythroid 2-related factor 2 (Nrf2) and other processes. Increased levels of ROS/RNS, generated from both endogenous (mitochondria, NADPH oxidases) and/or exogenous sources (radiation, certain drugs, foods, cigarette smoking, pollution) result in a harmful condition termed oxidative stress ("bad stress"). Although it is widely accepted, that many chronic diseases are multifactorial in origin, they share oxidative stress as a common denominator. Here we review the importance of oxidative stress and the mechanisms through which oxidative stress contributes to the pathological states of an organism. Attention is focused on the chemistry of ROS and RNS (e.g. superoxide radical, hydrogen peroxide, hydroxyl radicals, peroxyl radicals, nitric oxide, peroxynitrite), and their role in oxidative damage of DNA, proteins, and membrane lipids. Quantitative and qualitative assessment of oxidative stress biomarkers is also discussed. Oxidative stress contributes to the pathology of cancer, cardiovascular diseases, diabetes, neurological disorders (Alzheimer's and Parkinson's diseases, Down syndrome), psychiatric diseases (depression, schizophrenia, bipolar disorder), renal disease, lung disease (chronic pulmonary obstruction, lung cancer), and aging. The concerted action of antioxidants to ameliorate the harmful effect of oxidative stress is achieved by antioxidant enzymes (Superoxide dismutases-SODs, catalase, glutathione peroxidase-GPx), and small molecular weight antioxidants (vitamins C and E, flavonoids, carotenoids, melatonin, ergothioneine, and others). Perhaps one of the most effective low molecular weight antioxidants is vitamin E, the first line of defense against the peroxidation of lipids. A promising approach appears to be the use of certain antioxidants (e.g. flavonoids), showing weak prooxidant properties that may boost cellular antioxidant systems and thus act as preventive anticancer agents. Redox metal-based enzyme mimetic compounds as potential pharmaceutical interventions and sirtuins as promising therapeutic targets for age-related diseases and anti-aging strategies are discussed.

• Klíčová slova
• Aging, Antioxidants, Metals, Oxidative stress, ROS, Signaling pathways, Toxicity,
• MeSH
• antioxidancia * MeSH
• chronická nemoc MeSH
• lidé MeSH
• oxidační stres * MeSH
• reaktivní formy kyslíku MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• antioxidancia * MeSH
• reaktivní formy kyslíku MeSH

Sulfur mustard (SM) is a vesicant chemical warfare agent that persists as a serious menace from the viewpoint of acute and chronic toxicity, simple synthesis and no effective treatment currently being available. The two most deleterious basic molecular mechanisms in SM poisoning are: inflammation and over-activation of poly(ADP-ribose) polymerase and the resulting DNA alkylation. Oxidative stress is the common consequence of these pathway activations. In the present review, the significance of oxidative stress in SM poisoning is discussed along with research on antioxidant therapy as a suitable antidote. The temporal dynamics of the redox imbalance, the antioxidant depletion and impact this has on tissues are described as the pathologies induced by SM. Special attention is paid to ameliorating the damage using low molecular weight antioxidants. Melatonin, epigallocatechin gallate and flavone derivatives, in particular, have been studied in recent experiments. The suitability of these antioxidants for therapy purposes is considered in a separate chapter. The review concludes with a view to the future and the studies needed on antioxidant therapy as a countermeasure to SM poisoning.

• MeSH
• antioxidancia chemie   farmakologie   terapeutické užití   MeSH
• chemické bojové látky metabolismus   otrava   MeSH
• lidé MeSH
• oxidační stres účinky léků   MeSH
• poly(ADP-ribosa)-polymerasy metabolismus   MeSH
• poškození DNA účinky léků   MeSH
• yperit metabolismus   otrava   MeSH
• zánět chemicky indukované   farmakoterapie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• antioxidancia MeSH
• chemické bojové látky MeSH
• poly(ADP-ribosa)-polymerasy MeSH
• yperit MeSH

Various reactive oxygen species (ROS) may be produced from normal biochemical, essential metabolic processes or from external sources as exposure to a variety of agents presented in the environment. Lipids, proteins, carbohydrates and DNA are all capable of reacting with ROS and can be implicated in etiology of various human disorders (rheumatoid arthritis, reperfusion injury, atherosclerosis, lung diseases etc.). In the organism damage by ROS is counteracted with natural antioxidants (glutathione peroxidases, superoxide dismutases, catalase, glutathione, ubiquinol, uric acid, and essential minerals) and nutritional antioxidants from diet (i.e. vitamins E, C, carotenoids). Possible mechanisms of nutritional depletion and side effects of high intake are in the article described.

• MeSH
• antioxidancia škodlivé účinky   terapeutické užití   MeSH
• homeostáza MeSH
• karbonylace proteinů účinky léků   MeSH
• lidé MeSH
• oxidační stres účinky léků   MeSH
• peroxidace lipidů účinky léků   MeSH
• poškození DNA MeSH
• potravní doplňky * škodlivé účinky   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• vápník metabolismus   MeSH
• vitaminy škodlivé účinky   terapeutické užití   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• antioxidancia MeSH
• reaktivní formy kyslíku MeSH
• vápník MeSH
• vitaminy MeSH

Phytochemical investigations of Matricaria chamomilla L. (Asteraceae) stated the presence of several compounds with an established therapeutic and antioxidant potential. The chamomile non-enzymatic antioxidant system includes low molecular mass compounds, mainly polyphenols such as cinnamic, hydroxybenzoic and chlorogenic acids, flavonoids and coumarins. The objective of this work was to evaluate the role of the non-enzymatic antioxidant system after stimulation by ethylene in tetraploid chamomile plants. Seven days of ethylene treatment significantly increased the activity of phenylalanine ammonia-lyase, which influenced the biosynthesis of protective polyphenols in the first step of their biosynthetic pathway. Subsequently, considerable enhanced levels of phenolic metabolites with a substantial antioxidant effect (syringic, vanillic and caffeic acid, 1,5-dicaffeoylquinic acid, quercetin, luteolin, daphnin, and herniarin) were determined by HPLC-DAD-MS. The minimal information on the chlorogenic acids function in chamomile led to the isolation and identification of 5-O-feruloylquinic acid. It is accumulated during normal conditions, but after the excessive effect of abiotic stress, its level significantly decreases and levels of other caffeoylquinic acids enhance. Our results suggest that ethephon may act as a stimulant of the production of pharmaceutically important non-enzymatic antioxidants in chamomile leaves and thus, lead to an overall change in phytochemical content and therapeutic effects of chamomile plants, as well.

• Klíčová slova
• antioxidants, chamomile, chlorogenic acids, ethylene,
• MeSH
• antioxidancia metabolismus   MeSH
• biosyntetické dráhy fyziologie   MeSH
• ethyleny metabolismus   MeSH
• fenoly metabolismus   MeSH
• fenylalaninamoniaklyasa metabolismus   MeSH
• fyziologický stres fyziologie   MeSH
• heřmánek, heřmánkovec, rmen, rmenec metabolismus   MeSH
• kyselina chinová analogy a deriváty   metabolismus   MeSH
• kyselina chlorogenová metabolismus   MeSH
• kyseliny kávové metabolismus   MeSH
• listy rostlin metabolismus   MeSH
• Matricaria metabolismus   MeSH
• polyfenoly metabolismus   MeSH
• rostlinné extrakty metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antioxidancia MeSH
• caffeic acid MeSH Prohlížeč
• caffeoylquinic acid MeSH Prohlížeč
• ethyleny MeSH
• fenoly MeSH
• fenylalaninamoniaklyasa MeSH
• kyselina chinová MeSH
• kyselina chlorogenová MeSH
• kyseliny kávové MeSH
• polyfenoly MeSH
• rostlinné extrakty MeSH

The role of platelets in hemostasis may be influenced by alteration of the platelet redox state-the presence of antioxidants and the formation of reactive oxygen and nitrogen species. We investigated the effects of two antioxidants, resveratrol and trolox, on platelet activation. Trolox and resveratrol inhibited aggregation of washed platelets and platelet-rich plasma activated by ADP, collagen, and thrombin receptor-activating peptide. Resveratrol was a more effective agent in reducing platelet static and dynamic adhesion in comparison with trolox. The antioxidant capacity of resveratrol was, however, the same as that of trolox. After incubation of platelets with antioxidants, the resveratrol intraplatelet concentration was about five times lower than the intracellular concentration of trolox. Although both antioxidants comparably lowered hydroxyl radical and malondialdehyde production in platelets stimulated with collagen, TxB(2) levels were decreased by resveratrol much more effectively than by trolox. Cyclooxygenase 1 was inhibited by resveratrol and not by trolox. Our data indicate that antioxidants, apart from nonspecific redox or radical-quenching mechanisms, inhibit platelet activation also by specific interaction with target proteins. The results also show the importance of studying platelet activation under conditions of real blood flow in contact with reactive surfaces, e.g., using dynamic adhesion experiments.

• MeSH
• agregace trombocytů účinky léků   fyziologie   MeSH
• antioxidancia farmakologie   MeSH
• buněčná adheze účinky léků   fyziologie   MeSH
• chromany (dihydrobenzopyrany) farmakologie   MeSH
• cyklooxygenasa 1 metabolismus   MeSH
• hemostáza účinky léků   MeSH
• kolagen farmakologie   MeSH
• kultivované buňky MeSH
• lidé MeSH
• malondialdehyd metabolismus   MeSH
• resveratrol MeSH
• stilbeny farmakologie   MeSH
• thromboxan B2 metabolismus   MeSH
• trombocyty účinky léků   fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid MeSH Prohlížeč
• antioxidancia MeSH
• chromany (dihydrobenzopyrany) MeSH
• cyklooxygenasa 1 MeSH
• kolagen MeSH
• malondialdehyd MeSH
• resveratrol MeSH
• stilbeny MeSH
• thromboxan B2 MeSH

BACKGROUND AND OBJECTIVES: Blood is exposed to oxidation stress and therefore has a high antioxidant capacity (AOC). With the many factors increasing the demands on the AOC, there may be damage to erythrocytes by free radicals. This study was to investigate evidence of erythrocyte damage in stored donor blood and to affect this by premedication of blood donors. MATERIALS AND METHODS: Blood samples of 15 healthy donors were collected in CPDA-1 solution and analyzed immediately, and then again after 10 days of incubation at 4 degrees C and 1 day of incubation at 37 degrees C. Prior to incubation, the following parameters were evaluated: Na+, K+, malondialdehyde (MDA), hemoglobin (Hb), AOC in the supernatant, superoxide dismutase (SOD) in erythrocytes, and glutathione peroxidase (GSHPx) in whole blood. Blood donors of group 1 were not given any drugs or vitamins before blood sampling. The same blood donors were then supplemented with the following daily doses of antioxidants for 10 days before the next blood sampling: 36 mg of beta-carotene, 300 mg of vitamin E, 200 mg of vitamin C, and 40 mg of selenium. RESULTS: The blood from donors of group 2 had a significantly smaller increase in MDA, K+, and Hb, and a smaller decrease in Na+ and AOC in the supernatant compared with that of group 1, while the activity of SOD and GSHPx did not change during blood storage. CONCLUSIONS: These results suggest that antioxidants given to blood donors can improve red cell storage parameters by reducing cell damage caused by free radicals.

• MeSH
• antioxidancia MeSH
• dárci krve * MeSH
• erytrocyty MeSH
• konzervace krve * MeSH
• lidé MeSH
• oxidační stres MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antioxidancia MeSH

• MeSH
• antioxidancia terapeutické užití   MeSH
• kardiovaskulární nemoci prevence a kontrola   MeSH
• polyfenoly terapeutické užití   MeSH
• rostliny chemie   MeSH
• Publikační typ
• úvodníky MeSH
• Názvy látek
• antioxidancia MeSH
• polyfenoly MeSH