Antioxidants and cytoprotection

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Effects of ethanol and arachidonic acid pathway inhibitors on the effectiveness of gastric mucosa cytoprotection

Effects of ethanol and arachidonic acid pathway inhibitors on the effectiveness of gastric mucosa cytoprotection

Numerous experimental studies and clinical obser- vations indicate that the arachidonic acid (AA) path- way products are important elements of the natural protective system of the gastric mucosa. Many years ago, Robert showed the antiulcerous actions of pros- taglandins, initiating the studies on cytoprotection defined as the protective actions of an organism against damaging factors. According to Robert, cy- toprotection in the stomach consists in increased mucus secretion, intensified and modified mucous circulation and activated bicarbonate secretion to the stomach [33]. Prostaglandins, activating the mucus and bicarbonate secretion and dilating the vessels, intensify cytoprotection [28,32]. Moreover, cytoprotection is maintained due to the actions of antioxidants synthesised, among others, as a result of the generation of oxygen free radicals formed during inflammatory or haematogenic tissue inju- ries [31]. Leukotrienes, thromboxane and platelet
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NF-κB and Nrf2 as prime molecular targets for chemoprevention and cytoprotection with anti-inflammatory and antioxidant phytochemicals

NF-κB and Nrf2 as prime molecular targets for chemoprevention and cytoprotection with anti-inflammatory and antioxidant phytochemicals

Dissociation of the Nrf2-Keap1 complex is also assumed to be stimulated through the phosphorylation of Nrf2 by distinct upstream kinases such as MAPKs, PKC, PI3K, etc. As in the case of NF-jB, phosphorylation of Nrf2 is also considered to facilitate the interaction of this redox-sensi- tive transcription factor with CBP/p300. Many antioxidants derived from dietary and medicinal plants have been found to modulate Nrf2-Keap1 signaling, thereby potentiating cellular antioxidant capacity or facilitating detoxification of carcinogens and other toxicants [4, 5]. It is noteworthy that there is a good correlation between anti-inflammatory activity of some chemopreventive/cytoprotective agents and their ability to induce antioxidant gene expression [6]. In this context, it is interesting to note that Nrf2 plays a role in protecting cells from not only oxidative stress but also Fig. 1 Regulation of NF-jB activation by cellular signaling mole- cules. Upon stimulation of cells, activation of protein kinases such as phosphatidylinositol 3-kinase (PI3K), protein kinase C (PKC), c-Jun NH 2 -terminal kinase (JNK), and extracellular signal-regulated kinase
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Upregulation of HSP70 Extends Cytoprotection to Fish Brain under Xenobiotic Stress

Upregulation of HSP70 Extends Cytoprotection to Fish Brain under Xenobiotic Stress

An imbalance between proxidant and antioxidant leads to altered cell viability and damage to biological macromolecules resulting in the developement of oxidative stress (OS). Enriched poly unsaturated fatty acid (PUFA) and lowered antioxidants and related enzymes makes the brain highly susceptable to free radical induced oxidative stress (FRIOS). Peroxidation of unsaturated lipids in cell membranes produce unstable lipid hydroperoxides which is further decomposed to highly reactive product that threaten cell integrity. In addition, these products are converted to free radicals that can initiate the destructive cycle of lipid peroxidation chain reactions (Genestra, 2007). These free radicals are quenched by an array of antioxidants which can be enzymatic or non- enzymatic. Thioredoxin (Trx) is one of the redox components of the cell that exists either in a reduced form with dithiol or in an oxidized form, with an intramolecular disulfide bridge (Powis et al. 2000). The redox activity by reversible oxidation of its active center dithiol to disulfide is essential for its functions such as cell growth, apoptosis.
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Role of Vagus Nerve in Gastroduodenal Adaptation and Cytoprotection

Role of Vagus Nerve in Gastroduodenal Adaptation and Cytoprotection

participation of some hormones. Experiments with false feeding, similar to the Pavlov’s classic experiment, have shown that, in addition to the vagus nerve stimulation, the level of several gastric hormones was significantly increased. This set of regulators includes gastrin, cholecystokinin, histamine, gastrin-releasing peptide, ghrelin, etc. [8]. Also was observed a slight increase of some inhibitory hormones, such as pancreatic polypeptide YY (PYY), leptin, and secretin in the blood plasma [9]. The intensity of cerebral phase depends on multiple settings: activation of conditioned reflexes by the sense of smell and taste receptors of the tongue, and mechanical stimulation of the stomach and intestine chemoreceptors. Afferents activation of the gastroduodenal mucosa leads to the switching on of local (intramural) and vago-vagal (or extramural) reflexes that impact on the motility, mucus and secretion of the digestive juices and cytoprotection in GDA [10]. However, what signals determine the activation of afferent nerve fibers, and how does local protective system responses against the effects of aggressive exogenous and endogenous factors? - Little is known. This explains the interest in structure and functional role of sensory nerve endings.
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THE HEALTH BENEFITS AND RISKS OF ANTIOXIDANTS

THE HEALTH BENEFITS AND RISKS OF ANTIOXIDANTS

The ability to utilize oxygen provides benefit of metabolizing fats, proteins and carbohydrates for energy. Being highly reactive oxygen atom is capable of becoming part of potentially damaging molecules known as “free radicals”. Free radicals are not only capable of attacking the healthy cells of the body, but also causing them to lose their structure and function. 1 Free radicals have been implicated in the etiology of several human diseases as well as ageing. 2,3 Cell damage caused by free radicals appears to be a major contributor to aging and to degenerative diseases of aging such as cardiovascular disease, cataracts, cancer, brain dysfunction and immune system decline. 4 Overall, it is found that free radicals have been implicated in the pathogenesis of at least 50 diseases. 1 Antioxidants are able to scavenge free radicals from the body cells and thus prevent or reduce the damage caused by oxidation. 5 Rich diet of antioxidants may reduce the risk of many diseases.
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<p>Colon Targeting of Naringin for Enhanced Cytoprotection Against Indomethacin-Induced Colitis in Rabbits</p>

<p>Colon Targeting of Naringin for Enhanced Cytoprotection Against Indomethacin-Induced Colitis in Rabbits</p>

Methodology: This study involved the formulation of compression-coated tablets of nar- ingin employing mixtures of pH-sensitive Eudragit L100-55 (EUD-L100-55) and different time-dependent polymers including ethyl cellulose (EC), sodium alginate (ALG) and sodium carboxymethyl cellulose (SCMC). Drug – polymer interaction during release was assessed using Fourier transform-infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Tablets were evaluated in vitro. Surface morphology of the optimized tablets either before or after exposure to the different release media was examined employing scanning electron microscopy (SEM). Cytoprotection potential of the optimized tablets against indo- methacin-induced colitis in rabbits was screened and compared to core tablets through a histopathological examination of colon, measurement of serum perinuclear antineutrophil cytoplasmic antibodies (pANCA) and immunohistochemical localization of tumor necrosis factor-alpha (TNF- α ).
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Quantitative determination of low molecular weight antioxidants and their effects on different antioxidants in chicken blood plasma

Quantitative determination of low molecular weight antioxidants and their effects on different antioxidants in chicken blood plasma

In our research work we assume that participating anti- oxidants form a network which carry out regulation, in- ducibility, interactivity and balance between the members. To test such hypothesis it was necessary to develope suitable methodologies for assessing the amount of anti- oxidants and their activity in tissues and biological fluids. Obtained results may give us more rational recom- mendations for dietary intake, and help to explain the effects of specific antioxidants. Today, still many questions accompany the beneficial or harmful effects of LMWA

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Oxidative Stress and Salivary Antioxidants

Oxidative Stress and Salivary Antioxidants

Oxidative stress is caused by a shift in the balance between highly reactive molecules, such as reactive oxygen spe- cies, and antioxidant body’s defense system. Reactive oxygen species play a pivotal role in the human body and are produced by a living organism as a result of normal cellular metabolism and environmental factors, such as pollutants and cigarette smoke. However, their high activity might have important biological consequences. ROS can be considered as a significant mediator of damage to major biomolecules and cell structures. It is also well documented that oxidative stress takes part in a growing number of pathological states and diseases, especially when inflammation is prominent. Aerobic organisms have developed an antioxidant system and are effective in opposing the effect of ROS. These antioxidants can be divided into the following: enzymatic and non-enzymatic. In pathological conditions the antioxidant system may be overwhelmed, which leads to oxidative stress. The purpose of this mini-review is to introduce the important findings concerning the ROS and salivary antioxidants (Dent. Med. Probl. 2013, 50, 4, 461–466).
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Synergistic combinatorial antihyperlipidemic study of selected natural antioxidants; modulatory effects on lipid profile and endogenous antioxidants

Synergistic combinatorial antihyperlipidemic study of selected natural antioxidants; modulatory effects on lipid profile and endogenous antioxidants

Similarly the antioxidant effect of catechin, hesperidin, ferulic acid and quercetin were observed at low doses in- dividually up to certain levels but became pro-oxidant as the dose increased above that threshold level, while combinations presented enhanced effects at various doses [40]. This effect is due to the preventive behavior for one another. The same proposal was focused in current research to reduce the chances of single drug dose bulking, system saturation and negative effects. A study on oligomeric proanthocyanidins (OPC) reported dose dependent results up to certain doses [52]. Simi- larly in another study poor antihypertensive results were obtained in high doses [53], may be due to pro-oxidant effect [54] reducing its own activity. A parallel study on pterostilbene and quercetin revealed significant results in reducing lipid levels at lower doses but at higher doses the effect was not as predicted indicating the ceiling effect [55]. Niacin efficacy in combination with conventional drug therapies and natural antioxidants are already reported of providing synergistic effects on blood Table 4 Quantification of water soluble endogenous antioxidants levels in various test groups
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Antioxidants - A Boon of A Bane- An Update

Antioxidants - A Boon of A Bane- An Update

The discussion in this review shows that the biological effects of antioxidants in humans are controversial. Depending on the oxidative status of cells, antioxidants can be protective against cancer or cancer promoting. Since ROS induce oxidative carcinogenic damage in DNA, antioxidants can prevent cancer in healthy people harboring increased levels of ROS. However, since ROS in moderate concentrations act as indispensable mediators of cancer-protective apoptosis and phagocytosis, in people with a low ROS level, an excess of antioxidants can block these cancer-preventive mechanisms and interfere with apoptosis to further promote cancer.
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Macro Coumarins as Novel Antioxidants

Macro Coumarins as Novel Antioxidants

The antioxidant activities of individual compounds were tested against stable free radical 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH), hydrogen peroxide (H 2 O 2 ) and FRAP (ferric r[r]

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A REVIEW ON ROLE OF ANTIOXIDANTS IN DIABETES

A REVIEW ON ROLE OF ANTIOXIDANTS IN DIABETES

Diabetes mellitus is an insistent metabolic disorder characterized by an aberrantly upraised level of blood glucose due to the deficit in insulin secretion by the β-cells of the pancreas and/or resistance toward the exploit of hormone insulin associated with disturbances in the carbohydrates, lipids, and proteins metabolism which leads to long-term complications. International Diabetes Federation conferring 371 million people affected by diabetes and the number likely to elevate 552 million by 2030. Based on the previous experimental and clinical studies recommend that oxidative stress plays a main role in the pathogenesis of diabetes. This article reviews the role of antioxidants in diabetes [1].
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Oxidants, antioxidants and the ischemic brain

Oxidants, antioxidants and the ischemic brain

at pH·7.4 (Goldstein et al., 2003a). The compounds variously have selective SOD-like properties [Mn cyclic(II) polyamines (Salvemini et al., 1999)], modest catalase-like activity [Mn(III) salen derivatives (Baker et al., 1998) and Mn(III) porphyrins (Day et al., 1997)], potential to oxidize nitric oxide [oxoMn(V) salen derivatives) (Sharpe et al., 2002) and Mn(III) porphyrins (Spasojevic et al., 2000) and oxidized nitroxides, i.e. oxoammonium cations (Goldstein et al., 2004)], and ability to eliminate peroxynitrite [Mn(III) salen derivatives (Sharpe et al., 2002), Mn(III) porphyrins (Ferrer-Sueta et al., 2003) and oxoammonium cations (Goldstein et al., 2004)] or peroxynitrite-derived products such as nitrogen dioxide radical (nitroxides; Goldstein et al., 2004, 2003b) and carbonate radical [Mn(III) porphyrins (Ferrer-Sueta et al., 2003) and nitroxides (Goldstein et al., 2004)]. Reactivity of antioxidants towards a wide range of ROS/RNS would make them more versatile antioxidants, i.e. protective in different cellular environments. Mn(III) porphyrins have been most intensively investigated in models of cerebral ischemia/reperfusion. The cationic Mn(III) porphyrins, ortho N-ethylpyridylporphyrin (MnTE-2-PyP 5+ , AEOL 10113) and di-ortho N,N′-
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Reactive antioxidants for peroxide crosslinked polyethylene

Reactive antioxidants for peroxide crosslinked polyethylene

Although considerable amount of work has been published on the stabilisation and assessment of the lifetime performance of PEX pipes in the presence of thermal antioxidants, one of the main issues remains to be associated with the physical and chemical loss of conventional thermal antioxidants (AOs) which ultimately leads to brittle fracture and failure of the pipes [8-15]. The high free radical scavenging ability of hindered phenolic and aminic AOs, which are critical to their antioxidant action, would also inadvertently lead to their ‘sacrificial’ chemical loss due to their interference with the free radical crosslinking process [16-18]. In addition, antioxidant losses have been shown [9, 10] to occur through physical migration and leaching into the contact environment. This would not only compromise the long-term stabilising performance of the antioxidants but could give also health and safety concerns for potable water pipe applications.
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A Review of Natural Antioxidants In Medicinal Plants

A Review of Natural Antioxidants In Medicinal Plants

Natural antioxidants are widely distributed in medicinal plants. These natural antioxidants, especially polyphenols and carotenoids, exhibit a wide range of biological effects, including anti- inflammatory, anti-aging, anti-atherosclerosis and anticancer. The medicinal plants are crucial to explore the potential antioxidant sources and promote the application in functional foods. The present paper provides comprehensive informa- tion on the green extraction technologies of natu- ral antioxidants, assessment of antioxidant activi- ty at chemical and cellular based levels and their main resources from food and medicinal plants Oxygen free radicals induce damage due to peroxidation to biomembranes and also to DNA, which lead to tissue damage, thus cause occurrence of a number of diseases. Antioxidants neutralise the effect of free radicals through different ways and may prevent the body from various diseases. Antioxidants may be synthetic or natural. Synthetic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) have recently been reported to be dangerous for human health. Thus, the search for effective, non-toxic natural compounds with antioxidative activity has been intensified in recent years. The present review
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Antioxidants: saviors against mental diseases

Antioxidants: saviors against mental diseases

The diet in consideration involves variety of foods which contain legume, vegetables, cereal, dairy products, fruits and refreshing items. Estimation of the relevant antioxidants from each element of the diet have been calculated and added up to get the net result. The result so obtained has been compared with the daily intake amount necessary as precautionary measure against the diseases mentioned earlier and the medicinal doses essential for treatment of the patients already affected with the diseases.

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Oxidative stress and plant deriving antioxidants

Oxidative stress and plant deriving antioxidants

The interest of the scientific community in wild plants grows with the establishment of compounds showing biological activity and positive effects on the human body. The involvement of free radicals in the aging process and a number of chronic degenerative diseases like cancer, cardiovascular diseases, etc. has been proven. The preventive and curative role of antioxidants makes it an interesting subject for research base to create food with healthy and functional effects. By enriching the knowledge of plants, as an indispensable source of biologically active components, ways to use natural ingredients in foods with expected health effects are being looked for.
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Antioxidants Modify Diazepam Toxicity in Mice

Antioxidants Modify Diazepam Toxicity in Mice

Diazepam overdose causes CNS and respiratory depression which may lead to coma and death. Experimental data show that acute administration of high doses of diazepam results in a cascade of oxidative changes and significantly diminishes cell antioxidant defense, especially the intracellular levels of reduced glutathione [2]. In these conditions the role of antioxidants seems predictable.

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Dietary intake of antioxidants in the Czech RepublicDietary

Dietary intake of antioxidants in the Czech RepublicDietary

In Spain, coffee was also the largest source of antioxidant intake (44.5%), similar to results obtained in other countries. Other important contributors to the antioxidant intake included wine (approximately 14% of all antioxidants), fruits (13%), vegetables (including potatoes) (7%), nuts (4.4%), and pulses (3.5%). Cereals provided only 3% of the antioxidant capacity of the Spanish diet, while tea provided only 2.7% and vegetable oils less than 1% (Saura-Calixto & Goñi 2006). Unfortunately, this study did not evaluate the contribution of cocoa products to the intake of antioxidants. However, in a subsequent study, cocoa products were found to contribute between 7.3% and 9.5% of the antioxidant intake in Spain (depending on the method used for antioxidant capacity determination; Taberneto et al. 2006). Table 3. Intake of antioxidants (AO) from the particular food groups
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Antioxidants: Friend or foe for tuberculosis patients

Antioxidants: Friend or foe for tuberculosis patients

per se. Therefore, it is important to understand the role of vitamin E in various concentrations in presence and ab- sence of other antioxidants, on the re-ox capacity of in- tracellular nascent ROS. Similar examples may be cited with all the commonly used antioxidants and the role of commonly used antioxidants in intracellular ROS pro- duction/function is unclear as on date. Such knowledge is important keeping in mind the prevalence of the infec- tious diseases and the consumption habit of antioxidants of public at large. In this article the same will be at- tempted to be reviewed in the context of tuberculosis.
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