Oxyhalogen–Sulfur Chemistry: Kinetics and Mechanism of Oxidation of Tiopronin by Acidified Bromate and Aqueous Bromine

2015 ◽  
Vol 68 (2) ◽  
pp. 262 ◽  
Author(s):  
Wilbes Mbiya ◽  
Risikat Adigun ◽  
Thai Tran ◽  
Yadana Htwe ◽  
Reuben H. Simoyi
Keyword(s):  
Reaction Network ◽  
Clinical Applications ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Direct Reaction ◽  
Sulfinic Acid ◽  
Sulfenic Acid ◽  
Sulfur Chemistry ◽  
Thiyl Radicals ◽  
Wide Range

N-2-(Mercaptopropionyl)glycine (MPG) is a free-radical scavenger, a detoxicating synthetic aminothiol which also acts as an antioxidant with a wide range of clinical applications. The oxidation of MPG by aqueous bromine and acidified bromate has been studied by spectrophotometric techniques. The stoichiometry for the reaction of acidic bromate with MPG is 1 : 1, HS(CH3)CH(=O)N(H)CH2COOH + BrO3– → HO3S(CH3)CH(=O)N(H)CH2COOH + Br–, with reaction occurring only at the thiol centre. The involvement of thiyl radicals in the oxidation of MPG competes with a non-radical pathway involving two-electron oxidations of the sulfur centre. A bimolecular rate constant of 5.68 (±0.94) × 103 M–1 s–1 for the direct reaction of MPG with bromine was determined. Electrospray ionization spectral data show that MPG is oxidized through its sulfinic acid, by-passing the unstable sulfenic acid. A simplified reaction network consisting of 19 reactions was simulated and it gave a very good fit to the experimental data.

Elaeocarpus floribundus Bl. seeds as a new source of bioactive compounds with promising antioxidant and antimicrobial properties

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ayorinde V. Ogundele ◽  
Saikat Haldar ◽  
Archana Yadav ◽  
Archana M. Das
Keyword(s):  
Bioactive Compounds ◽  
Antioxidant Activities ◽  
Antimicrobial Properties ◽  
Ethanolic Extract ◽  
Ethyl Acetate Fraction ◽  
Antimicrobial Activities ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Medicinal Uses ◽  
Wide Range

AbstractThe fruits of Elaeocarpus floribundus Bl. (Elaeocarpaceae) are edible and are normally prescribed for treatment of diseases. The medicinal uses of the fruit create considerable quantities of seeds as wastes. In an attempt to valorise this biomass, we studied the antimicrobial and antioxidant activities of the ethanolic seed extract. The extract inhibited the growth of the tested pathogens and was also a very strong scavenger of DPPH free radicals. Consequently, the extract was phytochemically investigated and this study reports the initial isolation of five phenolic compounds from this source. The structures of the isolated compounds were elucidated by spectra analyses including HR-ESI-MS, 1D and 2D NMR experiments. The isolated compounds exhibited a wide range of antimicrobial activities against the tested pathogens. Gallic acid (4) showed the most activity against Bacillus subtilis with a minimum inhibitory concentration (MIC) value of 30 µg/mL, while the MIC values of the antimicrobial standards range between 10 and 35 µg/mL. Compound 4, crude ethanolic extract, and the ethyl acetate fraction were more a potent free radical scavenger of DPPH compared to ascorbic acid. Hence, the seeds of E. floribundus could be considered as a new source of bioactive compounds for pharmaceutical and food-related industries.

Oxyhalogen–Sulfur Chemistry: Oxidation of a Thiourea Dimer, Formamidine Disulfide, by Chlorine Dioxide

2013 ◽  
Vol 66 (3) ◽  
pp. 362 ◽  
Author(s):  
Bice S. Martincigh ◽  
Morgen Mhike ◽  
Kayode Morakinyo ◽  
Risikat Ajibola Adigun ◽  
Reuben H. Simoyi
Keyword(s):  
Chlorine Dioxide ◽  
Sulfonic Acid ◽  
Stoichiometric Ratio ◽  
Sulfinic Acid ◽  
Sulfenic Acid ◽  
Acidic Media ◽  
Sulfur Chemistry ◽  
Spectrometric Data ◽  
Oxidative Pathway ◽  
Formamidine Disulfide

The oxidation of formamidine disulfide, FDS, the dimer of thiourea, by aqueous chlorine dioxide has been studied in highly acidic and mildly acidic media. FDS is one of the possible oxidation intermediates formed in the oxidation of thiourea by oxyhalogens to urea and sulfate. The reaction is exceedingly slow, giving urea and sulfate with a stoichiometric ratio of 5 : 14 FDS to chlorine dioxide after an incubation period of up to 72 h and only in highly acidic media which discourages the disproportionation of chlorine dioxide to the oxidatively inert chlorate. Mass spectrometric data suggest that the oxidative pathway proceeds predominantly through the sulfinic acid, proceeding next to the products sulfate and urea, while by-passing the sulfonic acid. Transient formation of the unstable sulfenic acid was also not observed.

Melatonin reduces high levels of lipid peroxidation induced by potassium iodate in porcine thyroid

2019 ◽  
pp. 1-7 ◽  
Author(s):  
Paulina Iwan ◽  
Jan Stepniak ◽  
Malgorzata Karbownik-Lewinska
Keyword(s):  
Lipid Peroxidation ◽  
Oxidative Damage ◽  
Membrane Lipids ◽  
Chemical Properties ◽  
Iodine Concentration ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Protective Effects ◽  
Potassium Iodate ◽  
Hormone Synthesis

Abstract. Iodine is essential for thyroid hormone synthesis. Under normal iodine supply, calculated physiological iodine concentration in the thyroid is approx. 9 mM. Either potassium iodide (KI) or potassium iodate (KIO3) are used in iodine prophylaxis. KI is confirmed as absolutely safe. KIO3 possesses chemical properties suggesting its potential toxicity. Melatonin (N-acetyl-5-methoxytryptamine) is an effective antioxidant and free radical scavenger. Study aims: to evaluate potential protective effects of melatonin against oxidative damage to membrane lipids (lipid peroxidation, LPO) induced by KI or KIO3 in porcine thyroid. Homogenates of twenty four (24) thyroids were incubated in presence of either KI or KIO3 without/with melatonin (5 mM). As melatonin was not effective against KI-induced LPO, in the next step only KIO3 was used. Homogenates were incubated in presence of KIO3 (200; 100; 50; 25; 20; 15; 10; 7.5; 5.0; 2.5; 1.25 mM) without/with melatonin or 17ß-estradiol. Five experiments were performed with different concentrations of melatonin (5.0; 2.5; 1.25; 1.0; 0.625 mM) and one with 17ß-estradiol (1.0 mM). Malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA) concentration (LPO index) was measured spectrophotometrically. KIO3 increased LPO with the strongest damaging effect (MDA + 4-HDA level: ≈1.28 nmol/mg protein, p < 0.05) revealed at concentrations of around 15 mM, thus corresponding to physiological iodine concentrations in the thyroid. Melatonin reduced LPO (MDA + 4-HDA levels: from ≈0.97 to ≈0,76 and from ≈0,64 to ≈0,49 nmol/mg protein, p < 0.05) induced by KIO3 at concentrations of 10 mM or 7.5 mM. Conclusion: Melatonin can reduce very strong oxidative damage to membrane lipids caused by KIO3 used in doses resulting in physiological iodine concentrations in the thyroid.

OPTIMASI KONDISI EKSTRAKSI SENYAWA AKTIF ANTIOKSIDAN DARI BIJI ANGGUR

2019 ◽  
Vol 3 (2) ◽  
pp. 35
Author(s):  
Kartini Kartini ◽  
Azminah Azminah
Keyword(s):  
Free Radical ◽  
Optimum Condition ◽  
Active Compound ◽  
Grape Seed ◽  
Free Radical Scavenger ◽  
Water Bath ◽  
Radical Scavenger ◽  
Optimum Conditions ◽  
Ethanolic Solution ◽  
Reduced Pressure

In order to prepare standardized extract, optimization of extraction conditions of grape seed has been done. These conditions are type of menstrum (50, 70 and 96% of ethanolic solution), length of extraction (1, 2 and 4 hours) also method of evaporation (reduced pressure and opened air). Activity on free radical scavenger used as parameters to determine optimum conditions. Based on EC50 (concentration which scavenge 50% amount of free radical) can be concluded that optimum condition for extracting antioxidant active compound from grape seed are 70% ethanolic solution as menstrum, length of extraction 1 hour and evaporation on opened air use water bath.

scholarly journals Suppression of Inflammation-Associated Kidney Damage Post-Transplant Using the New PrC-210 Free Radical Scavenger in Rats

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1054
Author(s):  
Torsten R. Goesch ◽  
Nancy A. Wilson ◽  
Weifeng Zeng ◽  
Bret M. Verhoven ◽  
Weixiong Zhong ◽  
...  
Keyword(s):  
Protective Efficacy ◽  
Serum Levels ◽  
Rat Plasma ◽  
Free Radical Scavenger ◽  
Kidney Damage ◽  
Brown Norway ◽  
Radical Scavenger ◽  
Organ Protection ◽  
Antibody Mediated Rejection ◽  
Allograft Kidney

Allograft kidney transplantation, which triggers host cellular- and antibody-mediated rejection of the kidney, is a major contributor to kidney damage during transplant. Here, we asked whether PrC-210 would suppress damage seen in allograft kidney transplant. Brown Norway (BN) rat kidneys were perfused in situ (UW Solution) with or without added 30 mM PrC-210, and then immediately transplanted into Lewis (LEW) rats. 20 h later, the transplanted BN kidneys and LEW rat plasma were analyzed. Kidney histology, and kidney/serum levels of several inflammation-associated cytokines, were measured to assess mismatch-related kidney pathology, and PrC-210 protective efficacy. Twenty hours after the allograft transplants: (i) significant histologic kidney tubule damage and mononuclear inflammatory cell infiltration were seen in allograft kidneys; (ii) kidney function metrics (creatinine and BUN) were significantly elevated; (iii) significant changes in key cytokines, i.e., TIMP-1, TNF-alpha and MIP-3A/CCL20, and kidney activated caspase levels were seen. In PrC-210-treated kidneys and recipient rats, (i) kidney histologic damage (Banff Scores) and mononuclear infiltration were reduced to untreated background levels; (ii) creatinine and BUN were significantly reduced; and (iii) activated caspase and cytokine changes were significantly reduced, some to background. In conclusion, the results suggest that PrC-210 could provide broadly applicable organ protection for many allograft transplantation conditions; it could protect transplanted kidneys during and after all stages of the transplantation process—from organ donation, through transportation, re-implantation and the post-operative inflammation—to minimize acute and chronic rejection.

scholarly journals Possible Protective Role of Melatonin in Pediatric Infectious Diseases and Neurodevelopmental Pathologies

2020 ◽  
Vol 10 (01) ◽  
pp. e104-e109
Author(s):  
Antonio Molina-Carballo ◽  
Antonio Emilio Jerez-Calero ◽  
Antonio Muñoz-Hoyos
Keyword(s):  
Endothelial Cell ◽  
Free Radical ◽  
Chronic Administration ◽  
Protective Role ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Energetic Metabolism ◽  
Beneficial Effects ◽  
Molecular Crosstalk

AbstractMelatonin, produced in every cell that possesses mitochondria, acts as an endogenous free radical scavenger, and improves energetic metabolism and immune function, by complex molecular crosstalk with other intracellular compounds. There is greatly increasing evidence regarding beneficial effects of acute and chronic administration of high melatonin doses, in infectious, developmental, and degenerative pathologies, as an endothelial cell and every cell protectant.

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