Hydrophilic Vitamin Research Articles

Anti-oxidant vitamins reduce normal tissue toxicity induced by radio-immunotherapy.

Our purpose was to determine whether the administration of anti-oxidant vitamins could reduce dose-limiting toxicity from radio-immunotherapy (RAIT) and thereby allow higher escalation of RAIT doses. Lipophilic vitamins A and E were administered i.p. and hydrophilic vitamin C was administered i.m. for 14 days (3 days pre-RAIT through 11 days post-RAIT) alone or with bone marrow transplantation (BMT) to either BALB/c mice for toxicity studies or to nude mice bearing s.c. GW-39 human colonic cancer xenografts for therapy studies. The maximal tolerated dose (MTD) of RAIT ((131)I-MN14 anti-CEA IgG) that results in no lethality was determined for mice that did not receive vitamins or BMT and those that did receive one or both interventions. Body weight, peripheral white blood cell (pWBC) and platelet (PLT) counts and tumor growth were also measured. Administration of vitamins (equivalent of 3.5 IU/day vitamin A, 0.107 IU/day vitamin E and 4.0 mg/day ascorbic acid) to mice along with BMT increased the MTD by 42% and reduced body weight loss associated with RAIT. Vitamins also reduced the magnitude of RAIT-induced myelosuppression. As early as day 7 after RAIT, vitamins increased WBC counts following both a 400 microCi and a 500 microCi dose. On day 14 after the 400 microCi dose of RAIT (day 7 post-BMT), the additive effect of BMT and vitamin could be detected. Tumor growth was not adversely affected by vitamin administration.

Protection of low density lipoprotein oxidation by the antioxidant agent IRFI005, a new synthetic hydrophilic vitamin E analogue

The oxidative modification of low density lipoprotein (LDL) is thought to be an important factor in the initiation and development of atherosclerosis. Antioxidants have been shown to protect LDL from oxidation and to inhibit atherosclerosis development in animals. Potent synthetic antioxidants are currently being tested, but they are not necessarily safe for human use. We here characterize the antioxidant activity of IRFI005, the active metabolite of Raxofelast (IRFI0016) that is a novel synthetic analog of vitamin E under clinical development, and demonstrate that it prevents oxidative modification of LDL. IFI005 inhibited the oxidative modification of LDL, measured through the generation of MDA, electrophoretic mobility and apo B100 fluorescence. During the oxidation process IRFI005 was consumed with the formation of the benzoquinone oxidation product. The powerful antioxidant activity of IRFI005 is at least in part mediated by a chain breaking mechanism as it is an efficient peroxyl radical scavenger with a rate constant k (IRFI005 + LOO °) of 1.8 × 10 6 M −1s −1. 4. IRFI005 substantially preserved LDL-associated antioxidants, α-tocopherol and carotenoids, and when co-incubated with physiologic levels of ascorbate provoked a synergistic inhibition of LDL oxidation. Also the co-incubation of IRFI005 with Trolox caused a synergistic effect, and a lag phase in the formation of the trolox-benzoquinone oxidation product. A synergistic inhibition of lipid peroxidation was also demonstrated by co-incubating IRFI005 and α-tocopherol incorporated in linoleic acid micelles. These data strongly suggest that IRFI005 can operate by a recycling mechanism similar to the vitamin E/ascorbate system.

Peroxidase-catalyzed effects of indole-3-acetic acid and analogues on lipid membranes, DNA, and mammalian cells in vitro

This study aimed to explore the mechanisms and molecular parameters which control the cytotoxicity of derivatives of indole-3-acetic acid (IAA) when oxidatively activated by horseradish peroxidase (HRP). Lipid peroxidation was measured in liposomes, damage to supercoiled plasmid DNA assessed by gel electrophoresis, free radical intermediates detected by EPR following spin trapping, binding of IAA-derived products demonstrated by 3H labelling, stable products measured by HPLC, and cytotoxicity in hamster fibroblasts measured by clonogenic survival. IAA, and nine analogues more easily oxidized by HRP, caused lipid peroxidation in liposomes, but not detectably in membranes of hamster fibroblasts, and were cytotoxic after HRP activation to varying degrees. Cytotoxicity was not correlated with activation rate. The hydrophilic vitamin E analogue, Trolox, inhibited cytotoxicity, whereas loading fibroblasts with vitamin E was ineffective, consistent with an oxidative mechanism in which radical precursors to damage are intercepted by Trolox in the aqueous phase. However, two known oxidation products were nontoxic (the 3-carbinol and 3-aldehyde, both probably produced from 3-CH 2OO · peroxyl radicals via the 3-CH 2 · [skatolyl] radical following decarboxylation of the radical cation). The skatolyl radical from IAA was shown by EPR with spin trapping to react with DNA; electrophoresis showed binding to occur. Treatment of hamster fibroblasts with 5- 3H-IAA/HRP resulted in intracellular bound 3H. Together with earlier results, the new data point to unknown electrophilic oxidation products, reactive towards intracellular targets, being involved in cytotoxicity of the IAA/HRP combination, rather than direct attack of free radicals, excited states, or membrane lipid peroxidation.

Beneficial effects of raxofelast (IRFI 016), a new hydrophilic vitamin E-like antioxidant, in carrageenan-induced pleurisy.

1. Peroxynitrite is a strong oxidant that results from reaction between NO and superoxide. It has been recently proposed that peroxynitrite plays a pathogenetic role in inflammatory processes. Here we have investigated the therapeutic efficacy of raxofelast, a new hydrophilic vitamin E-like antioxidant agent, in rats subjected to carrageenan-induced pleurisy. 2. In vivo treatment with raxofelast (5, 10, 20 mg kg(-1) intraperitoneally 5 min before carrageenan) prevented in a dose dependent manner carrageenan-induced pleural exudation and polymorphonuclear migration in rats subjected to carrageenan-induced pleurisy. Lung myeloperoxidase (MPO) activity and malondialdehyde (MDA) levels, as well as histological organ injury were significantly reduced by raxofelast. 3. Immunohistochemical analysis for nitrotyrosine, a footprint of peroxynitrite, revealed a positive staining in lungs from carrageenan-treated rats. No positive nitrotyrosine staining was found in the lungs of the carrageenan-treated rats, which received raxofelast (20 mg kg 1) treatment. 4. Furthermore, in vivo raxofelast (5, 10, 20 mg kg(-1)) treatment significantly reduced peroxynitrite formation as measured by the oxidation of the fluorescent dihydrorhodamine 123, prevented the appearance of DNA damage, the decrease in mitochondrial respiration and partially restored the cellular level of NAD+ in ex vivo macrophages harvested from the pleural cavity of rats subjected to carrageenan-induced pleurisy. 5. In conclusion, our study demonstrates that raxofelast, a new hydrophilic vitamin E-like antioxidant agent, exerts multiple protective effects in carrageenan-induced acute inflammation.

Inhibitory effect of a hydrophilic alpha-tocopherol analogue, MDL 74,405, on generation of free radicals in stunned myocardium in dogs.

A previous study has demonstrated that the hydrophilic (alpha-tocopherol analogue, MDL 74,405, attenuates postischemic myocardial dysfunction ("stunning") in dogs. The present study was undertaken to determine directly whether the salutary effect of this drug on myocardial stunning results from inhibition of the generation of oxygen-derived free radicals. Open-chest dogs undergoing a 15-min coronary artery occlusion and 3 h of reperfusion received an intravenous infusion of either saline (controls, n = 7) or MDL 74,405 (n = 6) starting 30 min before coronary occlusion and ending 60 min after reflow at a dose of 0.3 mg/kg/h. To measure free radical production, all dogs received an intravenous infusion of the spin trap alpha-phenyl N-tert-butyl nitrone (PBN) and local coronary venous plasma was analyzed by electron paramagnetic resonance (EPR). In control dogs, the myocardial production of PBN adducts exhibited an initial burst immediately after the onset of reflow and remained elevated until 10 min after reperfusion. Dogs treated with MDL 74,405 demonstrated a marked decrease in PBN adduct production. This effect of MDL 74,405 could not be attributed to nonspecific factors such as differences in ischemic zone size, collateral flow, arterial pressure, heart rate, coronary flow or other hemodynamic variables. These results demonstrate that the hydrophilic vitamin E analogue, MDL 74,405, inhibits free radical generation after myocardial ischemia-reperfusion in vivo. This finding provides direct evidence that the salutary effects of MDL 74,405 on myocardial stunning are due to attenuation of oxidative stress.

The Influence of pH and Acetonitrile on the High Performance size Exclusion Profile of Proteins

Abstract The concentration of the organic modifier, acetonitrile and pH were altered to measure their effects on the retention of various hydrophilic proteins and vitamin B12 using high performance size exclusion chromatography (HPSEC). The best separations were obtained with 0.1 or 0.2M sodium phosphate in the pH range of 6.0 to 7.0. In the absence of TFA, up to 25% acetonitrile did not dramatically influence the size exclusion profile of the protein components. Although 30 to 40% acetonitrile and 0.1% TFA for elution was not acceptable for the chromatography of hydrophilic proteins, hydrophobic apolipoproteins were nicely resolved under these conditions.