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71.
Antioxidant properties and cytoprotective activity of flavonoids (rutin, dihydroquercetin, quercetin, epigallocatechin gallate (EGCG), epicatechin gallate (ECG)) were studied. All these compounds inhibited both NADPH- and CCl4-dependent microsomal lipid peroxidation, and the catechins were the most effective antioxidants. The I
50 values calculated for these compounds by regression analysis were close to the I
50 value of the standard synthetic antioxidant ionol (2,6-di-tert-butyl-4-methylphenol). The antiradical activity of flavonoids to O
2
was studied in a model photochemical system. Rate constants of the second order reaction obtained by competitive kinetics suggested flavonoids to be more effective scavengers of oxygen anion-radicals than ascorbic acid. By competitive replacement all flavonoids studied were shown to be chelating agents capable of producing stable complexes with transition metal ions (Fe2+, Fe3+, Cu2+). The flavonoids protected macrophages from asbestos-induced damage, and the protective effect increased in the following series: rutin < dihydroquercetin < quercetin < ECG < EGCG. The cytoprotective effect of flavonoids was in strong positive correlation with their antiradical activity to O
2
. 相似文献
72.
Oxidative damage following cerebral ischemia depends on reperfusion - a biochemical study in rat 总被引:11,自引:1,他引:10
Nita DA Nita V Spulber S Moldovan M Popa DP Zagrean AM Zagrean L 《Journal of cellular and molecular medicine》2001,5(2):163-170
The extent of brain injury during reperfusion appears to depend on the experimental pattern of ischemia/reperfusion. The goals of this study were: first, to identify the rate of free radicals generation and the antioxidant activity during ischemia and reperfusion by means of biochemical measurement of lipid peroxidation (LPO) and both enzymatic (superoxid dismutase - SOD, catalase - CAT, glutathion peroxidase - GPx) and non-enzymatic antioxidants activity (glutathione - GSH); and second, to try to find out how the pattern of reperfusion may influence the balance between free radical production and clearance. Wistar male rats were subject of four-vessel occlusion model (Pulsinelly & Brierley) cerebral blood flow being controlled by means of two atraumatic arterial microclamps placed on carotid arteries. The level of free radicals and the antioxidant activity were measured in ischemic rat brain tissue homogenate using spectrophotometrical techniques. All groups subjected to ischemia shown an increase of LPO and a reduction of the activity of enzymatic antioxidative systems (CAT, GPx, SOD) and non-enzymatic systems (GSH). For both groups subjected to ischemia and reperfusion, results shown an important increase of LPO but less significant than the levels found in the group with ischemia only. Statistically relevant differences (p<0.01) between continuous reperfusion and fragmented reperfusion were observed concerning the LPO, CAT, SOD and GSH levels, oxidative aggresion during fragmented reperfusion being more important. 相似文献
73.
The role of astroglia on the survival of dopamine neurons 总被引:5,自引:0,他引:5
Mena MA de Bernardo S Casarejos MJ Canals S Rodríguez-Martín E 《Molecular neurobiology》2002,25(3):245-263
Glial cells play a key role in the function of dopamine (DA) neurons and regulate their differentiation, morphology, physiological
and pharmacological properties, survival, and resistance to different models of DA lesion. Several studies suggest that glial
cells may be important in the pathogenesis of Parkinson’s disease (PD), a common neurodegenerative disorder characterized
by degeneration of the nigrostriatal DA system. In this disease the role of glia could be due to the excessive production
of toxic products such as nitric oxide (NO) or cytokines characteristic of inflammatory process, or related to a defective
release of neuroprotective agents, such as small antioxidants with free radical scavenging properties or peptidic neurotrophic
factors. 相似文献
74.
Antonella Del Corso Pier Giuseppe Vilardo Mario Cappiello Ilaria Cecconi Massimo Dal Monte Daniela Barsacchi Umberto Mura 《Archives of biochemistry and biophysics》2002,397(2):392-398
Glutathione is one of the most relevant antioxidants present in cells. It exerts its scavenging action through the involvement of efficient and ubiquitous enzymes. GSH on the other hand, because of its chemical features, can scavenge reactive oxygen species without the involvement of enzymatic systems. The study deals with the mobilization of GSH pool in a nonenzymatic antioxidant system by other physiological thiols (i.e., cysteine and cysteinyl-glycine), which are far more sensitive than GSH to oxidative conditions. These thiol compounds, in the presence of iron/EDTA, can promote oxygen activation through their oxidation to disulfides. GSH, through trans-thiolation reactions, can regenerate Cys and CysGly, which can then recycle, thus inducing a massive GSH oxidation. In these conditions, making use of bovine lens aldose reductase as a protein model, evidence is given that Cys and CysGly promote specific protein S-thiolation reactions. The possibility that GSH may be recruited in controlling cellular oxygen tension is considered. 相似文献
75.
Barnali?Baisakhi Jita?Patra Rabindra?K.?Panigrahy Brahma?B.?PandaEmail author 《Acta Physiologiae Plantarum》2003,25(4):357-363
Tolerant and non-tolerant clones of Chloris barbata Sw. obtained, respectively, from an erstwhile mercury contaminated solid waste dump site near a chloralkali plant and a non-contaminated
(control) site were subjected to cadmium-stress by growing the rooted cuttings in water containing CdSO4, 13 and 130 μM. Differences between the two clones in their response to cadmium-stress were noted in root growth, and also
with respect to certain biochemical parameters. Whereas catalase activity decreased and non protein-thiol levels increased
in the non-tolerant clone, the level of protein-thiol alone increased significantly in the tolerant clone in response to cadmium-stress.
No remarkable differences between the clones, however, were noted with respect to total soluble protein, peroxidase activity
and lipid peroxidation. Remarkably the two clones responded differently to buthionine sulfoximine, an inhibitor of glutathione
and/or phytochelatin synthesis, which inhibited root growth significantly in non-tolerant clone but not in the tolerant clone.
Buthionine sulfoximine, nonetheless, could potentate cadmium toxicity in either of the clones, but more effectively in the
tolerant clone. The high sensitivity of tolerant-clone to the combined treatment of BSO and Cd in the present study could,
therefore, be attributed to the cumulative oxidative stress generated synergistically by BSO and Cd. 相似文献
76.
This study was designed to measure the effect of iron supplementation on antioxidant status in iron-deficient anemia, including
the time for hemoglobin normalization and at the time of filling of iron body stores. The extent of plasma lipid peroxidation
was evaluated by measuring the levels of malondialdehyde and glutathione peroxidase (GSH-Px), and the activities of superoxide
dismutase (SOD) and catalase in 63 patients with iron-deficiency anemia before and after 6 wk of iron supplementation and
at the time when body iron stores are saturated. After 6 wk of iron supplementation, a significant decrease of oxidative stress
was observed in the treated subjects relative to controls (p<0.05). No significant differences existed between treated patients at 6 wk and at the end of the study. The erythrocyte levels
of catalase, SOD, and GSH-Px were significantly lower in treated patients relative to controls (p<0.05). These levels increased after 6 wk of supplementation (p<0.05) and showed no significant differences with those at the end of the study. 相似文献
77.
Increased resistance to oxidation of betalain-enriched human low density lipoproteins 总被引:5,自引:0,他引:5
Tesoriere L Butera D D'Arpa D Di Gaudio F Allegra M Gentile C Livrea MA 《Free radical research》2003,37(6):689-696
Betalains are natural pigments recently considered as compounds with potential antioxidative properties. In this work, ex vivo plasma spiking of pure either betanin or indicaxanthin, followed by isolation of low density lipoprotein (LDL), and measurement of its resistance to copper-induced oxidation, has been used to research if these betalains can bind to LDL and prevent oxidation of LDL lipids. When pooled human plasma from 10 healthy volunteers was incubated in the presence of 25-100 μM either betanin or indicaxanthin, incorporation of both compounds in LDL was observed, with a maximum binding of 0.52±0.08, and 0.51±0.06 nmoles of indicaxanthin and betanin, respectively, per mg LDL protein. Indicaxanthin-enriched and betanin-enriched LDL were more resistant than homologous native LDL to copper-induced oxidation, as assessed by the elongation of the induction period. The incorporated indicaxanthin, however, appeared twice as effective as betanin in increasing the length of the lag phase, while both compounds did not affect the propagation rate. Both betalains were consumed during the inhibition period of lipid oxidation, and delayed consumption of LDL-beta carotene. Indicaxanthin, but not betanin, prevented vitamin E consumption at the beginning of LDL oxidation, and prolonged the time of its utilization. The resistance of LDL to oxidation when vitamin E and indicaxanthin acted separately in a sequence, was lower than that measured when they were allowed to act in combination, indicating some synergistic interaction between the two molecules. No prooxidant effect over a large concentration range of either betanin or indicaxanthin was observed, when either betalain was added to the LDL system undergoing a copper-induced oxidation.
These results show than indicaxanthin and betanin may bind to LDL, and are highly effective in preventing copper-induced lipid oxidation. Interaction with vitamin E appears to add a remarkable potential to indicaxanthin in the protection of LDL. Although molecular mechanisms remain uncompletely understood, various aspects of the action of betanin and indicaxanthin in preventing LDL lipid oxidation are discussed. 相似文献
These results show than indicaxanthin and betanin may bind to LDL, and are highly effective in preventing copper-induced lipid oxidation. Interaction with vitamin E appears to add a remarkable potential to indicaxanthin in the protection of LDL. Although molecular mechanisms remain uncompletely understood, various aspects of the action of betanin and indicaxanthin in preventing LDL lipid oxidation are discussed. 相似文献
78.
Oxidative stress in Caenorhabditis elegans: protective effects of superoxide dismutase/catalase mimetics 总被引:3,自引:1,他引:2
The lifespan of Caenorhabditis elegans can be extended by the administration of synthetic superoxide dismutase/catalase mimetics (SCMs) without any effects on development or fertility. Here we demonstrate that the mimetics, Euk-134 and Euk-8, confer resistance to the oxidative stress-inducing agent, paraquat and to thermal stress. The protective effects of the compounds are apparent with treatments either during development or during adulthood and are independent of an insulin/IGF-I-like signalling pathway also known to affect thermal and oxidative stress resistance. Worms exposed to the compounds do not induce a cellular stress response and no detrimental effects are observed. 相似文献
79.
Effects of melatonin on oxidative-antioxidative status of tissues in streptozotocin-induced diabetic rats 总被引:6,自引:0,他引:6
In view of the antioxidant properties of melatonin, the effects of melatonin on the oxidative-antioxidative status of tissues affected by diabetes, e.g. liver, heart and kidneys, were investigated in streptozotocin (STZ)-induced diabetic rats in the present study. Concentrations of malondialdehyde (MDA) and reduced glutathione (GSH), and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the tissues were compared in three groups of 10 rats each (control non-diabetic rats (group I), untreated diabetic rats (group II) and diabetic rats treated with melatonin (group III)). In the study groups, diabetes developed 3 days after intraperitoneal (i.p.) administration of a single 60 mg kg(-1) dose of STZ. Thereafter, while the rats in group II received no treatment, the rats in group III began to receive a 10 mg kg(-1) i.p. dose of melatonin per day. After 6 weeks, the rats in groups II and III had significantly lower body weights and higher blood glucose levels than the rats in group I (p < 0.001 and p < 0.001, respectively). MDA levels in the liver, kidney and heart of group II rats were higher than that of the control group (p < 0.01, p < 0.05, p < 0.01, respectively) and diabetic rats treated with melatonin (p < 0.05). The GSH, GSH-Px and SOD levels increased in diabetic rats. Treatment with melatonin changed them to near control values. Our results confirm that diabetes increases oxidative stress in many organs such as liver, kidney and heart and indicate the role of melatonin in combating the oxidative stress via its free radical-scavenging and antioxidant properties. 相似文献
80.
Gastropathy and defense mechanisms in common bile duct ligated portal hypertensive rats 总被引:6,自引:0,他引:6
Kaur S Kaur U Tandon C Dhawan V Ganguly NK Majumdar S 《Molecular and cellular biochemistry》2000,203(1-2):79-85
Portal hypertensive gastropathy is associated with a broad spectrum of gastric mucosal damage inspite of decreased gastric acid secretion, suggestive of compromised endogenous protective mechanisms. To determine the mechanisms of damage in portal hypertensive gastropathy we measured lipid peroxidation, glutathione, antioxidant and lysosomal enzymes in gastric mucosal homogenates from male Wistar rats with elevated intrasplenic pulp pressure, eighteen days after common bile duct ligation. Thiobarbituric acid-reactive substances and lysosomal enzymes (-glucuronidase and acid phosphatase) were increased in the common bile duct ligated group as compared to the sham-operated group. The levels of antioxidant defense enzymes, superoxide dismutase, glutathione peroxidase, catalase and glutathione were decreased as compared to the sham-operated controls. Pre-operative vitamin E administration decreased mucosal lipid peroxidation increased the levels of antioxidant defense enzymes and lowered the lysosomal enzymes. The plasma vitamin E levels in this group were lower when compared to animals receiving it post-operatively. In conclusion, free radical and lysosomal enzyme mediated damage may play a role in portal hypertensive gastropathy. 相似文献