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Powerful Antioxidants (powerful + antioxidant)
Selected AbstractsMelatonin reduces experimental subarachnoid hemorrhage-induced oxidative brain damage and neurological symptomsJOURNAL OF PINEAL RESEARCH, Issue 3 2009Mehmet Ersahin Abstract:, Oxidative stress has detrimental effects in several models of neurodegenerative diseases, including subarachnoid hemorrhage (SAH). This study investigated the putative neuroprotective effect of melatonin, a powerful antioxidant, in a rat model of SAH. Male Wistar albino rats were divided as control, vehicle-treated SAH, and melatonin-treated (10 mg/kg, i.p.) SAH groups. To induce SAH, 0.3 mL blood was injected into cisterna magna of rats. Forty-eight hours after SAH induction, neurological examination scores were measured and the rats were decapitated. Brain tissue samples were taken for blood,brain barrier (BBB) permeability, brain water content, histological examination, or determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO), and Na+ -K+ -ATPase activities. Formation of reactive oxygen species in brain tissue samples was monitored by using a chemiluminescence (CL) technique. The neurological examination scores were increased in SAH groups on the second day of SAH induction and SAH caused a significant decrease in brain GSH content and Na+ -K+ -ATPase activity, which was accompanied with significant increases in CL, MDA levels, and MPO activity. On the other hand, melatonin treatment reversed all these biochemical indices as well as SAH-induced histopathological alterations, while increased brain water content and impaired BBB were also reversed by melatonin treatment. This study suggests that melatonin, which can easily cross BBB, alleviates SAH-induced oxidative stress and exerts neuroprotection by preserving BBB permeability and by reducing brain edema. [source] Ethanol Consumption Increases Nitric Oxide Production in Rats, and Its Peroxynitrite-Mediated Toxicity Is Attenuated by PolyenylphosphatidylcholineALCOHOLISM, Issue 6 2002Enrique Baraona Background: Nitric oxide generally mediates beneficial responses but becomes deleterious when coexistence with enhanced superoxide formation leads to the synthesis of peroxynitrite, a potent oxidant and nitrating agent. Methods: To study the effects of ethanol and polyenylphosphatidylcholine on nitric oxide metabolism and toxicity, 36 rats were pair-fed liquid diets with 36% of energy either as ethanol or as additional carbohydrate for 24 days and were killed 90 min after intragastric feeding. Half received polyenylphosphatidylcholine in the diet (3 g/liter), and the other half equivalent amounts of essential fatty acids and choline. Nitric oxide was measured by chemiluminescence in arterial blood and liver cytosol and as a product of the inducible nitric oxide synthase activity. Peroxynitrite formation was assessed by the increase in nitrotyrosine protein residues, measured immunochemically. Results: In blood, administration of ethanol with or without polyenylphosphatidylcholine doubled nitric oxide levels. In the liver, ethanol increased nitric oxide by 52% (p < 0.01), and polyenylphosphatidylcholine attenuated this effect. Ethanol consumption increased the cytosolic activity of the inducible nitric oxide synthase and induced microsomal cytochromes P-450 capable of producing both nitric oxide and superoxide. This was associated with an 18% (p < 0.01) increase in nitrotyrosine protein residues, products of peroxynitrite toxicity, which occurred predominantly in steatotic hepatocytes. Polyenylphosphatidylcholine attenuated these changes by decreasing the ethanol effect on both the cytosolic and the microsomal activities, in addition to acting as a powerful antioxidant. Acute administration of the same ethanol dose increased nitric oxide levels, but did not affect nitrotyrosine protein residues. Conclusions: Chronic, but not acute, ethanol administration increases peroxynitrite hepatotoxicity by enhancing concomitant production of nitric oxide and superoxide, both of which are prevented by polyenylphosphatidylcholine. [source] Influence of PROP taster status on the consumer acceptability of food made from tannin sorghumsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2009Rosemary I Kobue-Lekalake Abstract BACKGROUND: Condensed tannins in sorghum are powerful antioxidants, beneficial for health. However, tannin sorghums are believed to be unpalatable. The objective was to determine the influence of 6- n -propylthiouracil (PROP) taster status on consumer acceptability of food from tannin sorghums. Consumers (n = 194) classified by PROP taster status (super, medium and non) evaluated the appearance, flavour, overall liking and texture of sorghum rice from two tannin-free sorghums, PAN 8564 and Phofu, and two tannin sorghums, PAN 3860 (82 g catechin equivalents (CE) kg,1) and NS 5511 (18 g CE kg,1), with high antioxidant activity. RESULTS: The PROP tasters could distinguish differences among the sorghum cultivars varying in tannin content levels, finding PAN 3860 less acceptable than the other sorghums. The non tasters preferred all the cultivars equally, presumably because they could not detect taste (bitter and astringent) differences between the sorghums. With the exception of appearance, tannin sorghum NS 5511 was generally equally preferred by PROP tasters to tannin-free sorghums. CONCLUSION: There appear to some tannin sorghums that are palatable, even to PROP tasters, because the level of tannins is below a sensitivity threshold (ca 20 g CE kg,1). Hence such tannin sorghums could be used to produce acceptable high-antioxidant activity foods. Copyright © 2009 Society of Chemical Industry [source] Antioxidant and other biological activities of phenols from olives and olive oilMEDICINAL RESEARCH REVIEWS, Issue 1 2002Francesco Visioli Abstract Olive oil is the principal source of fats in the Mediterranean diet, which has been associated with a lower incidence of coronary heart disease and certain cancers. Phenolic compounds, e.g., hydroxytyrosol and oleuropein, in extra-virgin olive oil are responsible for its peculiar pungent taste and for its high stability. Recent findings demonstrate that olive oil phenolics are powerful antioxidants, both in vitro and in vivo, and possess other potent biological activities that could partially account for the observed healthful effects of the Mediterranean diet. © 2001 John Wiley & Sons, Inc. Med Res Rev, 22, No. 1, 65,75, 2002 [source] Comparative Study of Activities between Verbascoside and Rutin by Docking MethodMOLECULAR INFORMATICS, Issue 1 2003Kun Gao Abstract Verbascoside and rutin possess anti-cancer properties and are capable of repairing DNA damaged by oxygen radicals, acting as powerful antioxidants. Based on kinetic measurements and experiments on tumor cells, docking studies of the two ligand molecules with the receptor telomeric DNA fragments have been carried out. The docking calculations performed using JUMNA software showed that the both molecules can be docked into the minor groove of telomeric DNA and form complexes with suitable geometry for electron transfer between guanine radical and ligands. The reaction mechanism via the electron transfer process is further confirmed through energy calculations for transition states using MOPAC 93 program. Complexes can be formed without major distortion of DNA structure and are further stabilized by the interaction of DNA with the saccharide side-groups. By comparing their energies, the difference of activities of the two compounds can be explained. [source] Antioxidant Activity of Newly Synthesized 2,7-DiazaphenothiazinesARCHIV DER PHARMAZIE, Issue 5 2010Beata Morak-M, odawska Abstract A series of 19 derivatives of 2,7-diazaphenothiazine was synthesized and evaluated for their antioxidant activity bearing in mind the structural similarity with "classical" phenothiazines several of which are considered powerful antioxidants. Among the new derivatives that inhibited in vitro Fe2+/ascorbate-induced lipid peroxidation of rat liver microsomal membranes, several exhibited significant antioxidant activity with IC50 values in the range of 64,125 ,M. Although N -substitution led to a variable degree of antioxidant activity, the latter appears to correlate with the lipophilicity (expressed as clogP values) of the substituted derivatives. Reduced lipophilicity may also explain the relatively lower protection offered by these derivatives against lipid peroxidation when compared to their "classical" phenothiazine counterparts. Thus, modification of the phenothiazine structure by a substitution of two benzene rings with pyridine rings to form this new type of azaphenothiazines does not enhance antioxidant activity, although it retains it. [source] Carotenoids in evolutionary ecology: re-evaluating the antioxidant roleBIOESSAYS, Issue 10 2009Lorenzo Pérez-Rodríguez Abstract The antioxidant role of carotenoids in the living organism was proposed as a possible basis for the honesty of carotenoid-based signals. However, recent studies have questioned the relevance of carotenoids as powerful antioxidants in vivo. Current evidence does not seem to support the "antioxidant role" hypothesis, but it does not allow us to reject it either. This paper proposes some steps to solve this controversy, such as taking a dynamic approach to antioxidant responses, designing protocols that expose individuals to oxidative challenges, analyzing tissues other than blood, and obtaining measures of antioxidant capacity and oxidative damage simultaneously. However, it should be considered that, irrespective of their antioxidant potential, carotenoids might still give information on oxidative stress levels if they are particularly sensitive to free radicals. Finally, lumping together the immunostimulatory and antioxidant roles of carotenoids should be avoided as these functions are not necessarily associated. [source] | |||||||||||||