VII.—The oxidation of organic acids in presence of ferrous iron. Part I

Fenton, H. J. H.; Jones, HE

doi:10.1039/ct9007700069

Cited by 69 publications

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“…Under these conditions lipid peroxyl or alkoxyls formed may have resulted in oxidation of unsaturated lipids, as predicted by Halliwell and Gutteridge [15,16]. Following Fenton's demonstration [10] that ferrous salts can act ''catalytically'' with H 2 O 2 to yield hydroxyl radicals [20], we have observed that at millimolar levels, FeCl 2 has a dose-response relationship with the biophysical properties of surfactant. Iron is the most abundant transition metal in the body, and because of wide variations in its redox potential it can behave as a prooxidant to participate in free radical production.…”

Section: Discussionmentioning

confidence: 82%

Inhibitory Effects of Oxyradicals on Surfactant Function: Utilizing in Vitro Fenton Reaction

Amirkhanian

Merritt

1998

Lung

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The inhibitory effects of reactive oxygen species (ROS) on the surface tension-lowering abilities of three surfactants were compared: natural lung surfactant (NLS), KL4 surfactant containing synthetic peptide resembling the hydrophobic/hydrophilic domains of SP-B in an aqueous dispersion of phospholipids, and Survanta (SUR) containing SP-B and SP-C. The inhibitory concentrations of Fenton reactants (i.e. 0.65 mM FeCl2, 0.65 mM EDTA, 30 mM H2O2), deduced from dose-response plots of FeCl2 on minimum surface tension (MST) of SUR, were used to assess the Fenton effect on biophysical properties of various surfactants. Neither H2O2 (30 mM) nor FeCl2 with EDTA (both 0.65 mM) alone affected surfactant function, but when mixed together significantly increased (p < 0.01) the MST of SUR compared with KL4 (p < 0.05) in a FeCl2 concentration-dependent manner. This effect on NLS was not significant (p = 0.05) at similar phospholipid concentrations. Also, the range of increases in surface adsorption in mN/m at equilibrium surface tension (EST) was 27-40 for SUR, 36-44 for KL4, and 24-25 for NLS. We speculate that the presence of SP-A and the catalase content in NLS may have protective effects on inactivation of NLS by ROS. We conclude that the in vitro Fenton effect could be a valuable test system for comparing the inactivation range of surfactants by oxyradicals.

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Section: Discussionmentioning

confidence: 82%

Inhibitory Effects of Oxyradicals on Surfactant Function: Utilizing in Vitro Fenton Reaction

Amirkhanian

Merritt

1998

Lung

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“…Hence we examined the possibility of reversing oxyradical-induced physiological damage to lenses in culture by using pyruvate. Pyruvate was selected because in addition to its action as an oxyradical scavenger [12][13][14] , it has been found to act as a metabolic agonist and even inhibit glycation of tissue proteins associated with cataract formation [15,16] . The results were in accordance with this hypothesis.…”

Section: Introductionmentioning

confidence: 99%

Oxidative Damage to Lens in Culture: Reversibility by Pyruvate and Ethyl Pyruvate

2005

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It is generally believed that prophylactic intake of antioxidants is beneficial in delaying the onset of some aging manifestations such as cataract. However, whether such a supplementation will also be effective if the pathophysiogical process has already set in remains a largely open question. We examined this possibility with lens changes leading to cataract formation, since cataract genesis is intimately related to a continued generation of reactive oxygen species (ROS) in the aqueous humor. Since the formation of cataract is a well-defined progressive disease, starting with an early refractive change and leading to gradual enhancement of opacification, we hypothesized that even a belated start with an appropriate anti-oxidant could halt the pathological process and delay cataract maturation and vision impairment. Using lens cultures, we tested this hypothesis with pyruvate, known to be an effective and highly potent ROS scavenger. Adding pyruvate to the culture medium after lenses had sustained a 50% damage was significantly effective in preventing progress. This was apparent by better maintenance of the active rubidium transport activity in these lenses compared to controls without pyruvate treatment. Glutathione levels were also higher in the pyruvate group.

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“…Epidemiological studies investigating the association of antioxidant vitamins and a lowered incidence of cataracts have yielded results that are yet equivocal [13][14][15]. Hence we considered the desirability of studying the anti-cataractogenic potential of certain endogenously derived ROS scavengers such as pyruvate, a keto acid metabolite well-known to scavenge various ROS, with rate constants of reaction reaching the diffusion limit [16,17]. This is especially true with respect to hydroxyl radical [18].…”

Section: Research Articlementioning

confidence: 99%

Stimulation of Glycolysis in the Lens by Pyruvate. Implications in Protection against Oxidative Stress

Hegde¹,

Varma²

2015

J Metabolic Synd

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Objective: We have previously demonstrated that pyruvate protects the lens against oxidative stress in vitro as well as prevents cataract formation in vivo induced by oxidative stress. The effects have been attributed to its property of scavenging various reactive oxygen species (ROS). Additionally we hypothesize that the preventive effect is also due to its effect of stimulating glycolysis.Methods: This has been tested as follows: freshly isolated mice lenses were incubated for 4 hours in Tyrode medium containing 5-3 H-glucose as a tracer in the presence and absence of 2 mM sodium pyruvate and determining generation of 3 H2O and 3 H-lactate separated by column chromatography in succession through homemade anion exchange column followed by the phenylboronate and formate mini-columns.Results: the concentration of 3 H 2 O in the medium at the end of incubation was 95 µM in the controls incubated without pyruvate. In the presence of pyruvate (2 mM) added to the medium, the concentration of 3 H 2 O attained in the medium was 152 µM. The corresponding value expressed on the basis of lens weight was 46 nanomoles/lens in the control group vs. 88 nanomoles/lens with 2 mM pyruvate. Conclusion:As hypothesized, pyruvate was found to stimulate glycolysis in the lens as indicated by the enhanced generation of both 3 H 2 O and 3 H-lactate in lenses incubated in its presence as compared to controls. The observed metabolic stimulation is attributed to recycling of NAD generated during the reduction of pyruvate to lactate, NAD being the required cofactor in the oxidation of glyceraldehyde-3-phosphate to 1,3-diphosphoglycerate. That such stimulation is involved in its protective effect is also apparent by our previous reports showing higher ATP levels in the lenses cultured in medium generating ROS in the presence of pyruvate than in its absence, the primary source of ATP in lens being glycolysis.

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VII.—The oxidation of organic acids in presence of ferrous iron. Part I

Abstract: THE oxidation of various organic substances by means of hydrogen dioxide and other agents in presence of small quantities of iron salts, has formed the subject of a considerable number of communications to the Society and elsewhere (compare Fenton,

Cited by 69 publications

References 0 publications

Inhibitory Effects of Oxyradicals on Surfactant Function: Utilizing in Vitro Fenton Reaction

Inhibitory Effects of Oxyradicals on Surfactant Function: Utilizing in Vitro Fenton Reaction

Oxidative Damage to Lens in Culture: Reversibility by Pyruvate and Ethyl Pyruvate

Stimulation of Glycolysis in the Lens by Pyruvate. Implications in Protection against Oxidative Stress

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