ascorbic-acid and hydrazine

A one-pot synthesis method for the fabrication of biomass-derived activated carbon-zinc oxide (ZAC) nanocomposites using sugarcane bagasse as a carbon precursor and ZnCl2 as an activating agent is reported. For the first time, we used ZnCl2 as not only an activating agent and also for the synthesis of ZnO nanoparticles on the AC surface. ZAC materials with varying ZnO loading were prepared and characterized by a variety of analytical and spectroscopic techniques such as FE-SEM, FE-TEM, XRD, EA, XPS, and Raman spectroscopy. ZAC-modified glassy carbon electrodes (GCEs) were found to exhibit remarkable electrochemical properties for simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA) as well as hazardous pollutants such as hydrogen peroxide (H2O2) and hydrazine (N2H4) with desirable sensitivity, selectivity, and detection limits. Moreover, ZAC-modified stainless steel electrodes also showed superior performances for supercapacitor applications. The ZAC nanocomposites, which may be mass produced by the reported facile direct route from sugarcane bagasse, are not only eco-friendly but also cost-effective, and thus, are suitable as a practical platform for bio-sensing and energy storage applications.

Topics: Ascorbic Acid; Biosensing Techniques; Carbon; Cellulose; Chlorides; Dopamine; Electric Capacitance; Electric Power Supplies; Electrodes; Green Chemistry Technology; Hydrazines; Hydrogen Peroxide; Limit of Detection; Nanocomposites; Particle Size; Porosity; Saccharum; Uric Acid; Zinc Compounds; Zinc Oxide

A simple and efficient procedure was employed for the synthesis of N'-(1,4-naphtho-quinone-2-yl) isonicotinohydrazide (NIH) by the reaction of 2-hydroxy-1,4-naphthaquinone (lawsone) and isonicotinoyl hydrazine in methanol using ultrasonic irradiation. Lawsone is the principal dye, isolated from the leaves of henna (Lawsonia inermis). Structural modification was done on the molecule aiming to get a more active derivative. The structure of the parent compound and the derivative was characterized by elemental analyses, infrared, electronic, (1)H, (13)C NMR and GC-MS spectra. The fluorescence spectral investigation of the compound was studied in DMSO and ethanol. Single crystal X-ray diffraction studies reveal that NIH crystallizes in monoclinic space group. The DNA cleavage study was monitored by gel electrophoresis method. The synthesized compound was found to have significant antioxidant activity against DPPH radical (IC50=58 μM). The in vitro cytotoxic studies of the derivative against two human cancer cell lines MCF-7 (human breast cancer) and HCT-15 (human colon carcinoma cells) using MTT assay revealed that the compound exhibited higher cytotoxic activity with a lower IC50 value indicating its efficiency in killing the cancer cells even at low concentrations. These results suggest that the structural modifications performed on lawsone could be considered a good strategy to obtain a more active drug.

Topics: Ascorbic Acid; Biphenyl Compounds; Carbon-13 Magnetic Resonance Spectroscopy; Cell Death; Cell Line, Tumor; Crystallography, X-Ray; DNA Cleavage; Electrophoresis, Agar Gel; Free Radical Scavengers; Gas Chromatography-Mass Spectrometry; Humans; Hydrazines; Hydrogen Bonding; Isoniazid; Molecular Conformation; Picrates; Proton Magnetic Resonance Spectroscopy; Reference Standards; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared

Herein we report a synthesis of copper nanoparticles (Cu-NPs) in chitosan (Cts) media via a chemical reaction method. The nanoparticles were synthesized in an aqueous solution in the presence of Cts as stabilizer and CuSO(4)·5H(2)O precursor. The synthesis proceeded with addition of NaOH as pH moderator, ascorbic acid as antioxidant and hydrazine( )as the reducing agent. The characterization of the prepared NPs was done using ultraviolet-visible spectroscopy, which showed a 593 nm copper band. The Field Emission Scanning Electron Microscope (FESEM) images were also observed, and found to be in agreement with the UV-Vis result, confirming the formation of metallic Cu-NPs. The mean size of the Cu-NPs was estimated to be in the range of 35-75 nm using X-ray diffraction. XRD was also used in analysis of the crystal structure of the NPs. The interaction between the chitosan and the synthesized NPs was studied using Fourier transform infrared (FT-IR) spectroscopy, which showed the capping of the NPs by Cts.

Topics: Ascorbic Acid; Chitosan; Copper; Hydrazines; Hydrogen-Ion Concentration; Metal Nanoparticles; Particle Size; Sodium Hydroxide; Spectroscopy, Fourier Transform Infrared; Water; X-Ray Diffraction

We report the preparation, using electrochemical and solid-phase synthesis, and characterisation of a 26 member library of 13 dihydroxybenzene derivatives covalently attached to glassy carbon through ethylenediamine (EDA) and C(6)H(4)CH(2)NH linkers. First, Boc-protected EDA or Boc-NHCH(2)C(6)H(4) were electrochemically attached to the GC surface. After Boc-deprotection, dimethoxybenzoyl chlorides were coupled to the EDA and C(6)H(4)CH(2)NH linkers using solid-phase synthesis followed by deprotection of the methoxy groups to give the corresponding dihydroxybenzene compounds. Surface coverage and electrochemical parameters of the dihydroxybenzene modified electrodes were evaluated in parallel using cyclic voltammetry. The mid-peak potentials, E(mp), and surface coverages for the 13 dihydroxybenzene derivatives were found to be independent of the choice of linker. The mid-peak potentials of the immobilised dihydroxybenzene derivatives varied between 0.0 and 260 mV vs. SCE and their surface coverages varied between 0.07 and 1.1 nmol cm(-2), depending on the pattern of substitution of the dihydroxybenzene ring. The electrocatalytic activities of the library were evaluated for mediation of NADH oxidation, and the ortho-dihydroxybenzene derivatives were found to have higher catalytic activity.

Topics: Ascorbic Acid; Carbon; Catalysis; Electrochemistry; Electrodes; Glass; Hydrazines; Hydrogen-Ion Concentration; NAD; Oxidation-Reduction; Phenols

Second-generation carnosine analogs bearing the histidyl-hydrazide moiety have been synthesized and tested for their efficiency in scavenging malondialdehyde (MDA) derived from lipid peroxidation and for their ability to reverse the glycation process in the glucose-ethylamine Schiff base model. The data obtained indicate that this class of compounds maintains the activity profile of carnosine and is a suitable candidate for the treatment of disorders caused by oxidative stress.

Topics: Ascorbic Acid; Carnosine; Glycosylation; Histidine; Hydrazines; Iron; Lipid Peroxidation; Liposomes; Magnetic Resonance Spectroscopy; Malondialdehyde; Oxidative Stress; Schiff Bases; Thiobarbituric Acid Reactive Substances

A palladium hexacyanoferrate (PdHCF) film as an electrocatalytic material was obtained at an aluminum (Al) electrode by a simple electroless dipping method. The modified Al electrode demonstrated a well-behaved redox couple due to the redox reaction of the PdHCF film. The PdHCF film showed an excellent electrocatalytic activity toward the oxidation of hydrazine. The electrocatalytic oxidation of hydrazine was studied by cyclic voltammetry and rotating disk electrode voltammetry techniques. A calibration graph obtained for the hydrazine consisted of two segments (localized at concentration ranges 0.39-10 and 20-75 mM). The rate constant k and transfer coefficient alpha for the catalytic reaction and the diffusion coefficient of hydrazine in the solution D, were found to be 3.11 x 10(3) M(-1) s(-1), 0.52 and 8.03 x 10(-6) cm2 s(-1) respectively. The modified electrode was used to amperometric determination of hydrazine in photographic developer. The interference of ascorbic acid and thiosulfate were investigated and greatly reduced using a thin film of Nafion on the modified electrode. The modified electrode indicated reproducible behavior and a high level of stability during electrochemical experiments, making it particularly suitable for analytical purposes.

Topics: Aluminum; Ascorbic Acid; Calibration; Catalysis; Electrochemistry; Electrodes; Ferrocyanides; Fluorocarbon Polymers; Hydrazines; Oxidation-Reduction; Reproducibility of Results; Thiosulfates

A simplified method for inorganic phosphate determination has been developed. The method is sensitive, easy, economic, and applicable for estimation of phosphate released in both enzymatic and nonenzymatic reactions. A mixture of hydrazine sulfate and ascorbic acid was used as the reducing agent and the conditions for the development of the molybdenum blue color were optimized. Thus in the 4.0 ml assay system, 0.4 ml of the reducing agent solution containing 20 mg each of hydrazine sulfate and ascorbic acid per milliliter of 1.0 N H2SO4 gave a rapid optimum color development with absorption maximum at 820 nm. Color development showed a linear relationship up to 10 microg Pi concentration. Thus the method has a 2.5x higher range of Pi estimation than that of the Bartlett method. The molar extinction coefficient at 820 nm was higher than that obtained in the Bartlett procedure. Also the molybdenum blue color formed was stable up to 24 h. Under the standard assay conditions, interference from acid-labile phosphate as in the case of Na+,K+ ATPase was at the minimum. The applicability of the method for assay of microsomal Na+,K+ ATPase and glucose-6-phosphatase was checked in microassays (final volume 0.1 ml) in comparison to the conventional procedures which use 3-4 times higher volumes. Likewise the applicability of the method for phospholipid analysis was compared with that of the conventional Bartlett method. Under both test systems the results obtained by the micromethod were identical to those obtained by the conventional methods. In general the method, which rapidly produces quantitatively molybdenum blue color, not only is rapid economical, and convenient but also has wide applicability.

Topics: Animals; Ascorbic Acid; Color; Glucose-6-Phosphatase; Hydrazines; Liver; Molybdenum; Oxidation-Reduction; Phosphates; Phosphoric Monoester Hydrolases; Rats; Sodium-Potassium-Exchanging ATPase; Sulfuric Acids

Analogs (6-deoxyascorbic acid, erythroascorbic acid, and associated glycosides) of L-ascorbic acid (AA) contained in mushrooms were allowed to react with hydrazine to form osazones, and the conditions for separative determination by HPLC using a Zorbax SIL column were examined. Separation was started using solvent system 1 (ethylacetate/n-hexane/acetone/acetic acid, 50:50:1:1, v/v) as the mobile phase, and switching after 15 min to solvent system 2 (ethylacetate/acetone/acetic acid, 100:1:1, v/v). Detection was performed by absorbance at 500 nm. Because these analogs showed different formation rates for osazone, calibration curves were prepared for each substance. The recovery rate in the load test was 93-105%. By this method, AA and the analogs contained in eight species of edible mushrooms have been determined. The results revealed that: (1) the main constituents of all mushrooms are AA analogs rather than AA itself; (2) only one species contained AA in a very small amount (2 mumol/kg); (3) the types of AA analogs present differed according to the species of mushrooms, and (4) the total amount of AA analogs was between ca. 100-500 mumol/kg (2-9 mg per 100 g, converted to AA). In addition, a new AA analog was found in Pleurotus ostreatus and identified as 5-O-(alpha-D-xylopyranosyl)-D-erythroascorbic acid in structural analyses by NMR and other methods.

Topics: Ascorbic Acid; Basidiomycota; Chromatography, High Pressure Liquid; Glycosides; Hydrazines; Magnetic Resonance Spectroscopy; Spectrophotometry

Topics: Antineoplastic Agents; Antioxidants; Ascorbic Acid; Attitude to Health; Canada; Clinical Trials as Topic; Complementary Therapies; Cooperative Behavior; Government Agencies; Humans; Hydrazines; Neoplasms; Voluntary Health Agencies

Ribonucleotide reductase is a key enzyme for DNA synthesis. Its small component, named protein R2, contains a tyrosyl radical essential for activity. Consequently, radical scavengers are potential antiproliferative agents. In this study, we show that the reactivity of the tyrosyl radical towards phenols, hydrazines, hydroxyurea, dithionite and ascorbate can be finely tuned by relatively small modifications of its hydrophobic close environment. For example, in this hydrophobic pocket, Leu77-->Phe mutation resulted in a protein with a much higher susceptibility to radical scavenging by hydrophobic agents. This might suggest that the protein is flexible enough to allow small molecules to penetrate in the radical site. When mutations keeping the hydrophobic character are brought further from the radical (for example Ile74-->Phe) the reactivity of the radical is instead very little affected. When a positive charge was introduced (for example Ile74-->Arg or Lys) the protein was more sensitive to negatively charged electron donors such as dithionite. These results allow us to understand how tyrosyl radical sites have been optimized to provide a good stability for the free radical.

Topics: Amino Acid Substitution; Ascorbic Acid; Binding Sites; Crystallography, X-Ray; Dithionite; Escherichia coli; Free Radical Scavengers; Free Radicals; Hydrazines; Hydroxyurea; Kinetics; Leucine; Models, Structural; Mutagenesis, Site-Directed; Oxidation-Reduction; Phenols; Phenylalanine; Protein Conformation; Recombinant Proteins; Ribonucleotide Reductases; Substrate Specificity; Tyrosine

Topics: Antineoplastic Agents; Ascorbic Acid; Humans; Hydrazines; Male; Neoplasms; Smoking

By the use of electron spin resonance (ESR) spectroscopy and of spin-trapping technique, the effects of ascorbic acid on the formation of the free radical intermediates due to isoniazid (INAH) and its metabolites were investigated with a microsomal system. When alpha-(4-pyridyl 1-oxide)-N-tert butylnitrone (4-POBN) was used as a spin trapping agent, the ESR signal due to hydrazine (Hy) was formed to be most intensive among others. Therefore, it was presumed that Hy is a potent intermediate to cause an INAH-induced hepatic injury. In the presence of ascorbic acid (AA), the free radical formation of Hy, INAH and acetyl hydrazine was significantly inhibited, suggesting that AA may affect the INAH-hepatitis. By the addition of inhibitors of cytochrome P-450 like metyrapone and CO, the generation of the radical from Hy decreased, confirming that the radical is formed by the cytochrome P-450 dependent microsome systems. The 4-POBN-trapped radical species generated from Hy was presumed to be the hydrazyl radical by the results of mass spectrometry.

Topics: Animals; Ascorbic Acid; Chemical and Drug Induced Liver Injury; Free Radical Scavengers; Free Radicals; Hydrazines; In Vitro Techniques; Isoniazid; Microsomes, Liver; Rats; Rats, Inbred Strains

The activities of enzymes associated with the synthesis and degradation of L-ascorbic acid were studied in hydrazine-treated rats supplemented with pyridoxine. The effects of hydrazine in vitro were also examined on these enzymes. The activity of liver D-glucuronoreductase was reduced in hydrazine-treated rats even after receiving pyridoxine in excess. But, the decreased activities of liver and kidney dehydroascorbatases in hydrazine-treated rats were reversed by pyridoxine supplementation. Hydrazine in vitro could not inhibit the activity of liver D-glucuronoreductase or L-gulonooxidase. The drug was also unable to inhibit in vitro the activity of liver and kidney dehydroascorbatases. Studies with dialyzed liver homogenates showed that the diminished activity of D-glucuronoreductase in the liver of hydrazine-treated rats was maintained even after dialyzing the tissue preparations. In contrast, the reduced activity of dehydroascorbatase in the liver of hydrazine-treated rats was abolished following dialysis of the liver preparations. It has been suggested that the diminished activity of liver D-glucuronoreductase after hydrazine treatment might arise from the reduced synthesis of enzyme protein, while the reduction in the activity of dehydroascorbatase following hydrazine treatment could be ascribed to depletion in vivo of pyridoxal phosphate and/or to the involvement of some dialyzable factors.

Topics: Animals; Ascorbic Acid; Carbohydrate Dehydrogenases; Carboxylic Ester Hydrolases; Dehydroascorbatase; Hydrazines; Kidney; L-Gulonolactone Oxidase; Liver; Male; Pyridoxine; Rats; Sugar Alcohol Dehydrogenases

Topics: Ascorbic Acid; Complement System Proteins; Humans; Hydrazines; Kinetics

Topics: Ascorbic Acid; Dinitrobenzenes; Humans; Hydrazines; Vitamins

Topics: Ascorbic Acid; Hydrazines; Leukocytes; Vitamins

Topics: Ascorbic Acid; Hydrazines; Phenylhydrazines