Action of biologically-relevant oxidizing species upon uric acid. Identification of uric acid oxidation products

1990 ◽  
Vol 73 (2-3) ◽  
pp. 235-247 ◽  
Author(s):  
Harparkash Kaur ◽  
Barry Halliwell
Keyword(s):  
Uric Acid ◽  
Oxidation Products ◽  
Acid Oxidation ◽  
Biologically Relevant

scholarly journals Impact of Advanced Oxidation Products on Nanofiltration Efficiency

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 541 ◽  
Author(s):  
Renata Żyłła ◽  
Rafał Milala ◽  
Irena Kamińska ◽  
Marcin Kudzin ◽  
Marta Gmurek ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Membrane Filtration ◽  
Main Product ◽  
Membrane Separation ◽  
Negative Impact ◽  
Microscopic Analysis ◽  
Contact Angles ◽  
Oxidation Products ◽  
Acid Oxidation ◽  
Dihydroxybenzoic Acid

The aim of the work was to determine the influence of salicylic acid (SA) oxidation products on the effectiveness of their further removal in the membrane filtration process. Two commercial polyamide-based polymer membranes, HL (GE Osmonics) and TS80 (TriSepTM), were used and characterized by SEM microscopic analysis, contact angles, and free surface energy. The products of salicylic acid oxidation, 2,3- and 2,5-dihydroxybenzoic acid and catechol, were determined and their impact on the removal of unreacted salicylic acid in the nanofiltration process was investigated. It was also checked to what extent and why they were retained or not by the membranes. The results of the research have shown that the main product of salicylic acid oxidation, 2,3-dihydroxybenzoic acid, has a negative impact on the retention of salicylic acid in the nanofiltration stage, while the other product, catechol, improves SA retention. The determined values of contact angles correlate well with solubility (S) of the tested compounds, which increases in the following order SSA < S2,3-DHBA < SCAT, while the contact angle of the membrane decreases. Nevertheless, it has been shown that some oxidation products can penetrate the environment due to poorer membrane separation properties of these products.

Chlorogenic Acid Oxidation by a Crude Peroxidase Preparation: Biocatalytic Characteristics and Oxidation Products

2009 ◽  
Vol 5 (1) ◽  
pp. 243-251 ◽  
Author(s):  
Ali Osman ◽  
Ayman El Agha ◽  
Dimitris P. Makris ◽  
Panagiotis Kefalas
Keyword(s):  
Chlorogenic Acid ◽  
Oxidation Products ◽  
Acid Oxidation

scholarly journals Determination of uric acid in human serum by an enzymatic method using N-methyl-N-(4-aminophenyl)-3-methoxyaniline reagent

2003 ◽  
Vol 68 (8-9) ◽  
pp. 691-698 ◽  
Author(s):  
Milena Jelikic-Stankov ◽  
Predrag Djurdjevic ◽  
Dejan Stankov
Keyword(s):  
Uric Acid ◽  
Human Serum ◽  
Limit Of Detection ◽  
Ascorbate Oxidase ◽  
Acid Oxidation ◽  
Uric Acid Concentration ◽  
Enzymatic Method ◽  
Limit Of Quantification ◽  
Relative Standard

In this work a new enzymatic method for the determination of uric acid in human serum has been developed. The method is based on the oxidative coupling reaction between the N-methyl-N-(4-aminophenyl)-3-methoxyaniline (NCP) reagent and the hydrogen ? donor reagent N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3-methylaniline (TOOS), in the system involving three enzymes: uricase, peroxidase and ascorbate oxidase. Using this method uric acid could be determined in concentrations up to 1.428 mmol/L, with a relative standard deviation of up to 1.8 %. The effect of the medium pH and the NCP concentration on the linearity of the chromogen absorbance versus the uric acid concentration curve was investigated. The influence of the uricase activity on the maximum rate of uric acid oxidation was also examined. The use of the NCP reagent demonstrated a more precise and more sensitive determination of the uric acid compared to the determination with 4-aminoantipyrine (4-AA) as the coupling regent. The sensitivity of the method determined from the calibration curve was 0.71 absorbance units per mmol/L of uric acid; the limit of detection was LOD = 0.0035 mmol/L and the limit of quantification was LOQ = 0.015 mmol/L of uric acid.

scholarly journals Hydrogen Sulfide and Persulfides Oxidation by Biologically Relevant Oxidizing Species

Antioxidants ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 48 ◽  
Author(s):  
Dayana Benchoam ◽  
Ernesto Cuevasanta ◽  
Matías Möller ◽  
Beatriz Alvarez
Keyword(s):  
Hydrogen Sulfide ◽  
Oxidation Products ◽  
Physiological Effects ◽  
Metal Centers ◽  
Biologically Relevant ◽  
Mammalian Tissues ◽  
Sulfenic Acids ◽  
Electrophilic Character

Hydrogen sulfide (H2S/HS–) can be formed in mammalian tissues and exert physiological effects. It can react with metal centers and oxidized thiol products such as disulfides (RSSR) and sulfenic acids (RSOH). Reactions with oxidized thiol products form persulfides (RSSH/RSS–). Persulfides have been proposed to transduce the signaling effects of H2S through the modification of critical cysteines. They are more nucleophilic and acidic than thiols and, contrary to thiols, also possess electrophilic character. In this review, we summarize the biochemistry of hydrogen sulfide and persulfides, focusing on redox aspects. We describe biologically relevant one- and two-electron oxidants and their reactions with H2S and persulfides, as well as the fates of the oxidation products. The biological implications are discussed.

scholarly journals Oxidation of Alkylaromatics

2007 ◽  
Vol 4 (1) ◽  
pp. 1-13 ◽  
Author(s):  
T. S. S. Rao ◽  
Shubhra Awasthi
Keyword(s):  
Transition Metal ◽  
Benzoic Acid ◽  
Oxidation Product ◽  
Alkali Metals ◽  
Oxidation Products ◽  
Metal Salts ◽  
Acid Oxidation ◽  
Transition Metal Salts ◽  
Strong Acids ◽  
Primary Oxidation

Hydroperoxide atα-position to the aromatic ring is the primary oxidation product formed. In all cases monoalkylbenzenes lead to the formation of benzoic acid. Oxidation in the presence of transition metal salts not only accelerate but also selectively decompose the hydroperoxides. Alkyl naphthalenes mainly produce the corresponding naphthalene carboxylic acids. Hock-rearrangement by the influence of strong acids converts the hydroperoxides to hemiacetals. Peresters formed from the hydroperoxides undergo Criegee rearrangement easily. Alkali metals accelerate the oxidation while CO2as co-oxidant enhances the selectivity. Microwave conditions give improved yields of the oxidation products.

scholarly journals Sex Differences in Biomarkers Associated With Insulin Resistance in Obese Adolescents: Metabolomic Profiling and Principal Components Analysis

2014 ◽  
Vol 99 (12) ◽  
pp. 4730-4739 ◽  
Author(s):  
Dorothee Newbern ◽  
Pinar Gumus Balikcioglu ◽  
Metin Balikcioglu ◽  
James Bain ◽  
Michael Muehlbauer ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Insulin Resistance ◽  
Uric Acid ◽  
Fatty Acid ◽  
Acid Oxidation ◽  
Z Score ◽  
Obese Adolescents ◽  
Metabolic Signature ◽  
Components Analysis

Objective Obesity and insulin resistance (IR) predispose to type 2 diabetes mellitus. Yet only half of obese adolescents have IR and far fewer progress to type 2 diabetes mellitus. We hypothesized that amino acid and fatty acid metabolites may serve as biomarkers or determinants of IR in obese teens. Research Design and Methods Fasting blood samples were analyzed by tandem mass spectrometry in 82 obese adolescents. A principal components analysis and multiple linear regression models were used to correlate metabolic components with surrogate measures of IR: homeostasis model assessment index of insulin resistance (HOMA-IR), adiponectin, and triglyceride (TG) to high-density lipoprotein (HDL) ratio. Results Branched-chain amino acid (BCAA) levels and products of BCAA catabolism were higher (P &lt; .01) in males than females with comparable body mass index (BMI) z-score. In multivariate analyses, HOMA-IR in males correlated positively with BMI z-score and a metabolic signature containing BCAA, uric acid, and long-chain acylcarnitines and negatively with byproducts of complete fatty acid oxidation (R2 = 0.659, P &lt; .0001). In contrast, only BMI z-score correlated with HOMA-IR in females. Adiponectin correlated inversely with BCAA and uric acid (R2 = 0.268, P = .0212) in males but not females. TG to HDL ratio correlated with BMI z-score and the BCAA signature in females but not males. Conclusions BCAA levels and byproducts of BCAA catabolism are higher in obese teenage boys than girls of comparable BMI z-score. A metabolic signature comprising BCAA and uric acid correlates positively with HOMA-IR in males and TG to HDL ratio in females and inversely with adiponectin in males but not females. Likewise, byproducts of fatty acid oxidation associate inversely with HOMA-IR in males but not females. Our findings underscore the roles of sex differences in metabolic function and outcomes in pediatric obesity.

scholarly journals Tetragonia tetragonoides (Pall.) Kuntze (New Zealand Spinach) Prevents Obesity and Hyperuricemia in High-Fat Diet-Induced Obese Mice

Nutrients ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1087 ◽  
Author(s):  
Young-Sil Lee ◽  
Seung-Hyung Kim ◽  
Heung Yuk ◽  
Geung-Joo Lee ◽  
Dong-Seon Kim
Keyword(s):  
Uric Acid ◽  
New Zealand ◽  
High Fat Diet ◽  
Body Weight Gain ◽  
Gastrointestinal Diseases ◽  
Acid Oxidation ◽  
Obese Mice ◽  
High Fat ◽  
Edible Plant ◽  
Garcinia Cambogia

Tetragonia tetragonoides (Pall.) Kuntze, called New Zealand spinach (NZS), is an edible plant used in salad in Western countries and has been used to treat gastrointestinal diseases in traditional medicine. We examined the anti-obesity and anti-hyperuricemic effects of NZS and the underlying mechanisms in high-fat diet (HFD)-induced obese mice. Mice were fed a normal-fat diet (NFD); high-fat diet (HFD); HFD with 75, 150, or 300 mg/kg NZS extract; or 245 mg/kg Garcinia cambogia (GC) extract. NZS decreased body weight gain, total white adipose tissue (WAT), liver weight, and size of adipocytes and improved hepatic and plasma lipid profiles. With NZS, the plasma levels of the leptin and uric acid were significantly decreased while the levels of the adiponectin were increased. Furthermore, NZS decreased the expression levels of adipogenesis-related genes and xanthine oxidoreductase (XOR), which is involved in uric acid production, while increasing that of proteins associated with fatty acid oxidation. UPLC analysis revealed that NZS contained 6-methoxykaempferol-3-O-β-d-glucosyl(1′′′→2′′)-β-d-glucopyranoside, 6-methoxykaempferol-3-O-β-d-glucosyl(1′′′→2′′)-β-d-glucopyranosyl-(6′′′′-caffeoyl)-7-O-β-d-glucopyranoside, and 6,4′-dimethoxykaempferol-3-O-β-d-glucosyl(1′′′→2′′)-β-d-glucopyranosyl-(6′′′′-caffeoyl)-7-O-β-d-glucopyranoside. These results suggest that NZS exerts anti-obesity, anti-hyperlipidemia, and anti-hyperuricemic effects in HFD-induced obese mice, which are partly explained by regulation of lipid-metabolism-related genes and proteins and decreased expression of XOR.

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