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Journal articles on the topic 'Pyrogallol oxidation'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Mendes, Vanda, Rita Vilaça, Victor de Freitas, Pedro Moradas Ferreira, Nuno Mateus, and Vítor Costa. "Effect of Myricetin, Pyrogallol, and Phloroglucinol on Yeast Resistance to Oxidative Stress." Oxidative Medicine and Cellular Longevity 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/782504.

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The health beneficial effects of dietary polyphenols have been attributed to their intrinsic antioxidant activity, which depends on the structure of the compound and number of hydroxyl groups. In this study, the protective effects of pyrogallol, phloroglucinol, and myricetin on the yeastSaccharomyces cerevisiaewere investigated. Pyrogallol and myricetin, which have a pyrogallol structure in the B ring, increased H2O2resistance associated with a reduction in intracellular oxidation and protein carbonylation, whereas phloroglucinol did not exert protective effects. The acquisition of oxidative stress resistance in cells pretreated with pyrogallol and myricetin was not associated with an induction of endogenous antioxidant defences as assessed by the analysis of superoxide dismutase and catalase activities. However, myricetin, which provided greater stress resistance, prevented H2O2-induced glutathione oxidation. Moreover, myricetin increased the chronological lifespan of yeast lacking the mitochondrial superoxide dismutase (Sod2p), which exhibited a premature aging phenotype and oxidative stress sensitivity. These findings show that the presence of hydroxyl groups in the ortho position of the B ring in pyrogallol and myricetin contributes to the antioxidant protection afforded by these compounds. In addition, myricetin may alleviate aging-induced oxidative stress, particularly when redox homeostasis is compromised due to downregulation of endogenous defences present in mitochondria.

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2

Sutanto, Susanto, and Nasikin. "Solubility and Antioxidant Potential of a Pyrogallol Derivative for Biodiesel Additive." Molecules 24, no. 13 (July 2, 2019): 2439. http://dx.doi.org/10.3390/molecules24132439.

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Biodiesel is a renewable plant-based fuel as an alternative for fossil diesel fuel which has many advantages. However, its high content of unsaturated fatty acid causes an oxidation instability during storage. Numerous additives have been used and developed to overcome this problem such as the application of phenolic compound-based antioxidants. Pyrogallol is reported to be one of the best phenolic antioxidants for biodiesel. Unfortunately, pyrogallol has a low solubility in oil solution. In this research, pyrogallol solubility is increased by preparing a pyrogallol derivative through a reaction between pyrogallol and methyl linoleate in the presence of radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). The spectrophotometric method was used for solubility test. Antioxidant potential was examined using acid value determination during a four-week storage period as well as the Rancimat test to see its performance under accelerated oxidation conditions. The reaction produced a molecule which has a molecular weight of 418 g/mol, representing pyrogallol derivative which has a new C–O covalent bond with methyl linoleate. The result was confirmed by using nuclear magnetic resonance (1H-NMR, 13C-NMR, and 2D-HMQC) resulting in a molecular structure of methyl (10E,12E)-9-(2,6-dihydroxyphenoxy)octadeca-10,12-dienoate and its isomer methyl (9E,11E)-13-(2,6-dihydroxyphenoxy)octadeca-9,11-dienoate with a yield of 12.86% and selectivity of 21.05% on the basis of pyrogallol. Compared to pyrogallol, tert-butylhydroquinone (TBHQ), and gallic acid, the pyrogallol derivative has the highest solubility and acid value stability in palm oil biodiesel. The Rancimat induction time (IP) result of the pyrogallol derivative is higher than the biodiesel and is above the accelerated oxidation test American Society for Testing and Materials (ASTM) D 6751 standard.

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3

Mohos, Violetta, Attila Pánovics, Eszter Fliszár-Nyúl, Gabriella Schilli, Csaba Hetényi, Přemysl Mladěnka, Paul W. Needs, Paul A. Kroon, Gábor Pethő, and Miklós Poór. "Inhibitory Effects of Quercetin and Its Human and Microbial Metabolites on Xanthine Oxidase Enzyme." International Journal of Molecular Sciences 20, no. 11 (May 31, 2019): 2681. http://dx.doi.org/10.3390/ijms20112681.

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Quercetin is an abundant flavonoid in nature and is used in several dietary supplements. Although quercetin is extensively metabolized by human enzymes and the colonic microflora, we have only few data regarding the pharmacokinetic interactions of its metabolites. Therefore, we investigated the interaction of human and microbial metabolites of quercetin with the xanthine oxidase enzyme. Inhibitory effects of five conjugates and 23 microbial metabolites were examined with 6-mercaptopurine and xanthine substrates (both at 5 μM), employing allopurinol as a positive control. Quercetin-3′-sulfate, isorhamnetin, tamarixetin, and pyrogallol proved to be strong inhibitors of xanthine oxidase. Sulfate and methyl conjugates were similarly strong inhibitors of both 6-mercaptopurine and xanthine oxidations (IC50 = 0.2–0.7 μM); however, pyrogallol inhibited xanthine oxidation (IC50 = 1.8 μM) with higher potency vs. 6-MP oxidation (IC50 = 10.1 μM). Sulfate and methyl conjugates were approximately ten-fold stronger inhibitors (IC50 = 0.2–0.6 μM) of 6-mercaptopurine oxidation than allopurinol (IC50 = 7.0 μM), and induced more potent inhibition compared to quercetin (IC50 = 1.4 μM). These observations highlight that some quercetin metabolites can exert similar or even a stronger inhibitory effect on xanthine oxidase than the parent compound, which may lead to the development of quercetin–drug interactions (e.g., with 6-mercaptopurin or azathioprine).

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4

RIAHI, SIAVASH, ABDOLMAJID BAYANDORI MOGHADDAM, MOHAMMAD REZA GANJALI, and PARVIZ NOROUZI. "DETERMINATION OF THE OXIDATION POTENTIALS OF PYROGALLOL AND SOME OF ITS DERIVATIVES: THEORY AND EXPERIMENT." Journal of Theoretical and Computational Chemistry 06, no. 02 (June 2007): 331–40. http://dx.doi.org/10.1142/s0219633607003015.

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The Oxidation potentials of pyrogallol and some of its derivatives in aqueous solutions have been calculated. The calculations have been performed using ab initio molecular orbital calculations (HF), and density functional theory (DFT) with the inclusion of entropic and thermochemical corrections to yield free energies of redox reactions. The polarizable continuum model is used to describe the solvent. It was also obtained experimentally with the aid of an electrochemical technique (cyclic voltammetry). The theoretical and experimental values for the oxidation potential of the studied pyrogallol and some derivatives are in excellent agreement with each other and there is only a discrepancy of 0.025 V and 0.020 V for B3LYP and HF methods, respectively, between experimental and theoretical results. The agreement mutually verifies the accuracy of the experimental method and the validity of the applied mathematical model.

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5

Li, Yan, Yosuke Matsuo, Yoshinori Saito, and Takashi Tanaka. "Three New Oxidation Products Produced from Epigallocatechin-3-O-gallate and Epicatechin-3-O-gallate." Natural Product Communications 11, no. 2 (February 2016): 1934578X1601100. http://dx.doi.org/10.1177/1934578x1601100214.

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During chemical studies on uncharacterized black tea polyphenols, the enzymatic oxidation of a mixture of epigallocatechin-3- O-gallate (1) and epicatechin-3- O-gallate (2) was examined, and three new dimeric products together with six known catechin dimers were isolated. Two of the new compounds have tricyclo[5.2.2.02,6]undecane and tricyclo[5.2.1.02,6]decane carboxyl structures generated by oxidative coupling between two pyrogallol-B-rings of 1. Another new product was a dimer connected by a C-C bond between the B-ring of 1 and a galloyl group of 2.

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6

Lee, Jo-Won, Sohee Yoon, Y. Martin Lo, Haohao Wu, Sook-Young Lee, and BoKyung Moon. "Intrinsic polyphenol oxidase-like activity of gold@platinum nanoparticles." RSC Advances 5, no. 78 (2015): 63757–64. http://dx.doi.org/10.1039/c5ra07636f.

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Au@Pt NPs showed PPO mimetic activity over a wider range of pH and temperatures compared to PPO. In the oxidation of all substrates, Au@Pt NPs exhibited higher affinity to the substrates, especially to catechol and pyrogallol, compared with PPO.

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7

Ong, Hwai Chyuan, M. Mofijur, A. S. Silitonga, D. Gumilang, Fitranto Kusumo, and T. M. I. Mahlia. "Physicochemical Properties of Biodiesel Synthesised from Grape Seed, Philippine Tung, Kesambi, and Palm Oils." Energies 13, no. 6 (March 12, 2020): 1319. http://dx.doi.org/10.3390/en13061319.

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The production of biodiesel using vegetable oil is an effective way to meet growing energy demands, which could potentially reduce the dependency on fossil fuels. The aim of this study was to evaluate grape seed (Vitis vinifera), Philippine tung (Reutealis trisperma), and kesambi (Schleichera oleosa) oils as potential feedstocks for biodiesel production to meet this demand. Firstly, biodiesels from these oils were produced and then their fatty acid methyl ester profiles and physicochemical properties were evaluated and compared with palm biodiesel. The results showed that the biodiesel produced from grape seed oil possessed the highest oxidation stability of 4.62 h. On the other hand, poor oxidation stability was observed for Philippine tung biodiesel at 2.47 h. The poor properties of Philippine tung biodiesel can be attributed to the presence of α-elaeostearic fatty acid. Furthermore, synthetic antioxidants (pyrogallol) and diesel were used to improve the oxidation stability. The 0.2 wt.% concentration of pyrogallol antioxidant could increase the oxidation stability of grape seed biodiesel to 6.24 h, while for kesambi and Philippine tung, biodiesels at higher concentrations of 0.3% and 0.4 wt.%, respectively, were needed to meet the minimum limit of 8 h. The blending of biodiesel with fossil diesel at different ratios can also increase the oxidation stability.

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8

Medina-Escriche, J., A. Sevillano-Cabeza, M. Martín-Penella, and M. Llobat-Estelles. "Spectrophotometric determination of bromate by the oxidation of Pyrogallol Red." Analyst 110, no. 12 (1985): 1467–71. http://dx.doi.org/10.1039/an9851001467.

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9

Iranpoor, N., N. Maleki, S. Razi, and A. Safavi. "Spectrophotometric determination of vanadium in different oxidation states with pyrogallol." Talanta 39, no. 3 (March 1992): 281–84. http://dx.doi.org/10.1016/0039-9140(92)80033-a.

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10

Guardiola, Francesc, Sandra Garcia-Cruset, Ricard Bou, and Rafael Codony. "Artifactual Oxidation of Cholesterol During the Analysis of Cholesterol Oxidation Products: Protective Effect of Antioxidants." Journal of AOAC INTERNATIONAL 87, no. 2 (March 1, 2004): 493–98. http://dx.doi.org/10.1093/jaoac/87.2.493.

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Abstract To study the influence of the addition of various antioxidants and their combinations on the artifactual oxidation of cholesterol during analysis, 2 factorial experiments were performed in duplicate. In the first experiment, 2 amounts of the following antioxidants were assayed: ethylene-diaminetetraacetic acid (EDTA) disodium salt (0 and 1 mg), pyrogallol (0 and 600 μg), and butylated hydroxytoluene (BHT; 0 and 600 μg); in the second, EDTA disodium salt (0 and 1 mg), ascorbyl palmitate (0 and 600 μg), and BHT (0 and 600 μg). Under low oxidative conditions of dim light, evaporation of solvents at low temperatures, and cold saponification in darkness under nitrogen atmosphere, the addition of antioxidants showed no further protective effect. Furthermore, the presence of ascorbyl palmitate significantly increased the formation of cholesterol- 5β,6β-epoxide, and 7β-hydroxycholesterol.

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11

Li, Shuhuai, Jianping Li, Qingyu Lin, and Xiaoping Wei. "A molecularly imprinted sensor based on an electrochemiluminescent membrane for ultratrace doxycycline determination." Analyst 140, no. 13 (2015): 4702–7. http://dx.doi.org/10.1039/c5an00416k.

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A new electrochemical luminescence sensor was developed based on a molecularly imprinted membrane prepared by electropolymerization of pyrogallol doped with alizarin red. The ECL signal was produced by the oxidation of the polypyrogallol polymer, which was then reacted with alizarin red, and enhanced by doxycycline molecules due to energy transfer.

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12

Puvvada, Nagaprasad, Pravas Kumar Panigrahi, Dhritabrata Mandal, and Amita Pathak. "Shape dependent peroxidase mimetic activity towards oxidation of pyrogallol by H2O2." RSC Advances 2, no. 8 (2012): 3270. http://dx.doi.org/10.1039/c2ra01081j.

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13

Abrash, Henry I., Dorcas Shih, Woodrow Elias, and Farshad Malekmehr. "A kinetic study of the air oxidation of pyrogallol and purpurogallin." International Journal of Chemical Kinetics 21, no. 6 (June 1989): 465–76. http://dx.doi.org/10.1002/kin.550210609.

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14

Martins, N. C. T., M. F. C. G. Silva, J. A. L. Silva, J. J. R. F. Silva, C. Paliteiro, and A. J. L. Pombeiro. "Electrocatalytic Oxidation of Pyrogallol by an Amavadin Model-A Preliminary Study." Portugaliae Electrochimica Acta 19, no. 3 (2001): 367–70. http://dx.doi.org/10.4152/pea.200103367.

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15

Nasr, Bensalah, Trabelsi Hsen, and Gadri Abdellatif. "Electrochemical treatment of aqueous wastes containing pyrogallol by BDD-anodic oxidation." Journal of Environmental Management 90, no. 1 (January 2009): 523–30. http://dx.doi.org/10.1016/j.jenvman.2007.12.007.

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16

Evmiridis, Nicholaos P., Athanasios G. Vlessidis, and Nicholas C. Thanasoulias. "Chemical Analysis through CL-Detection Assisted by Periodate Oxidation." Bioinorganic Chemistry and Applications 2007 (2007): 1–10. http://dx.doi.org/10.1155/2007/92595.

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The progress of the research work of the author and his colleagues on the field of CL-emission generated by pyrogallol oxidation and further application for the direct determination of periodate and indirect or direct determination of other compounds through flow-injection manifold/CL-detection set up is described. The instrumentation used for these studies was a simple flow-injection manifold that provides good reproducibility, coupled to a red sensitive photomultiplier that gives sensitive CL-detection. In addition, recent reports on studies and analytical methods based on CL-emission generated by periodate oxidation by other authors are included.

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17

Evmiridis, Nicholas P. "Prospects of using chemiluminescence emission generated during oxidation of pyrogallol with periodate for the determination of pyrogallol with flow injection." Analyst 113, no. 7 (1988): 1051. http://dx.doi.org/10.1039/an9881301051.

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18

Lokhat, David, Mike Oliver, and Milan Carsky. "Preparation of iron oxide nanocatalysts and application in the liquid phase oxidation of benzene." Polish Journal of Chemical Technology 17, no. 2 (June 1, 2015): 43–46. http://dx.doi.org/10.1515/pjct-2015-0027.

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Abstract A series of iron oxide nanocatalysts were prepared using an ultrasonically assisted co-precipitation technique. Molybdenum promoted Fe3O4 and Fe2O3 were prepared from the original materials by wet impregnation using a solution of ammonium molybdate. The catalysts were tested in the liquid phase oxidation of benzene at atmospheric pressure and at 60°C using molecular oxygen. Phenol yields between 7% and 14.5% were obtained. The major products were pyrogallol and catechol.

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19

Medina-Escriche, J., A. Sevillano-Cabeza, and M. de la Guardia-Cirugeda. "Kinetic-spectrophotometric determination of chromium(VI) by the oxidation of pyrogallol red." Analyst 110, no. 6 (1985): 719. http://dx.doi.org/10.1039/an9851000719.

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20

Lan, Jing, Xirong Huang, Ming Hu, Weifeng Liu, Yuezhong Li, Yinbo Qu, and Peiji Gao. "Mechanistic studies on the effect of veratryl alcohol on the lignin peroxidase catalyzed oxidation of pyrogallol red in reversed micelles." Open Chemistry 5, no. 3 (September 1, 2007): 672–87. http://dx.doi.org/10.2478/s11532-007-0032-x.

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AbstractThe lignin peroxidase (LiP) catalyzed oxidation of pyrogallol red (PR) in the absence and presence of veratryl alcohol (3,4-dimethoxybenzyl alcohol, VA) was carried out in bis (2-ethylhexyl) sulfosuccinate sodium (AOT)/ polyoxyethylene lauryl ether (Brij30) reversed micelles to elucidate the role of VA. Results indicated that VA could accelerate the LiP catalyzed oxidation of PR, especially at low H2O2 concentrations. Unlike in bulk aqueous medium, the protection of LiP by VA in the present medium was relatively unsubstantial, even at high H2O2 concentrations. Analysis of data from a series of experiments showed that the enhancement of the PR oxidation caused by VA was mainly due to the indirect oxidation of PR by VA+∙ from the LiP catalyzed oxidation of VA. It was also found that at the same protector concentration (40 μM), VA (the physiological substrate of LiP) was less effective than PR (a phenolic compound) in protecting LiP from the H2O2 derived inactivation. This novel phenomenon deserves further study.

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21

Llobat-Estelles, M., A. Sevillano-Cabeza, and J. Medina-Escriche. "Kinetic-catalytic determination of cobalt by oxidation of Pyrogallol Red by hydrogen peroxide." Analyst 111, no. 2 (1986): 193. http://dx.doi.org/10.1039/an9861100193.

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22

Feng, Pi-Shan, Sheng-Ming Wang, Wan-Yu Su, and Shu-Hua Cheng. "Electrochemical Oxidation and Sensitive Determination of Pyrogallol at Preanodized Screen-Printed Carbon Electrodes." Journal of the Chinese Chemical Society 59, no. 2 (January 23, 2012): 231–38. http://dx.doi.org/10.1002/jccs.201100384.

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23

Nozaki, Osamu, Xiaoying Ji, and Larry J. Kricka. "New enhancers for the chemiluminescent peroxidase catalysed chemiluminescent oxidation of pyrogallol and purpurogallin." Journal of Bioluminescence and Chemiluminescence 10, no. 3 (May 1995): 151–56. http://dx.doi.org/10.1002/bio.1170100303.

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24

Shi, Qiaofang, and Shaolin Mu. "Preparation of Pt/poly(pyrogallol)/graphene electrode and its electrocatalytic activity for methanol oxidation." Journal of Power Sources 203 (April 2012): 48–56. http://dx.doi.org/10.1016/j.jpowsour.2011.11.077.

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25

Evmiridis, Nicholaos P. "Effect of hydroxylamine on chemiluminescence intensity generated during the oxidation of pyrogallol with periodate." Analyst 112, no. 6 (1987): 825. http://dx.doi.org/10.1039/an9871200825.

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26

Ensafi, Ali Asghar, and Elham Mirmomtaz. "Electrocatalytic oxidation of hydrazine with pyrogallol red as a mediator on glassy carbon electrode." Journal of Electroanalytical Chemistry 583, no. 2 (September 2005): 176–83. http://dx.doi.org/10.1016/j.jelechem.2005.01.042.

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27

Spasojevic, Dragica, Milos Prokopijevic, Olivera Prodanovic, Marilen Pirtea, Ksenija Radotic, and Radivoje Prodanovic. "Immobilization of chemically modified horse radish peroxidase within activated alginate beads." Chemical Industry 68, no. 1 (2014): 117–22. http://dx.doi.org/10.2298/hemind121122036s.

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Immobilization of horse radish peroxidase (HRP) within alginate beads was improved by chemical modification of the enzyme and polysaccharide chains. HRP and alginate were oxidized by periodate and subsequently modified with ethylenediamine. Highest specific activity of 0.43 U/ml of gel and 81 % of bound enzyme activity was obtained using aminated HRP and alginate oxidized by periodate. Immobilized enzyme retained 75 % of original activity after 2 days of incubation in 80 % (v/v) dioxane and had increased activity at basic pH values compared to native enzyme. During repeated use in batch reactor for pyrogallol oxidation immobilized peroxidase retained 75 % of original activity.

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28

Li, Yan, Takashi Tanaka, and Isao Kouno. "Oxidative coupling of the pyrogallol B-ring with a galloyl group during enzymatic oxidation of epigallocatechin 3-O-gallate." Phytochemistry 68, no. 7 (April 2007): 1081–88. http://dx.doi.org/10.1016/j.phytochem.2007.01.005.

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29

Faúndez, M., M. Rojas, P. Bohle, C. Reyes, M. E. Letelier, M. E. Aliaga, H. Speisky, E. Lissi, and C. López-Alarcón. "Pyrogallol red oxidation induced by superoxide radicals: Application to evaluate redox cycling of nitro compounds." Analytical Biochemistry 419, no. 2 (December 2011): 284–91. http://dx.doi.org/10.1016/j.ab.2011.08.048.

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30

Kivevele, Thomas, and Zhongie Huan. "Mungongo Seeds Oil (Schinziophyton rautanenii) as a Potential Source of Bio-Diesel." Applied Mechanics and Materials 472 (January 2014): 780–84. http://dx.doi.org/10.4028/www.scientific.net/amm.472.780.

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Biodiesel from mungongo seeds oil (Schinziophyton rautanenii) was investigated in the present study to determine its suitability for use as substitute of petro diesel. The fuel properties of Mungongo Oil Methyl ester (MOME) such as cetane number, kinematic viscosity, oxidative stability, lubricity, cloud point, pour point, cold filter plugging point, flash point, acid value, density, higher heating value, free and total glycerol were determined and compared with global biodiesel standards such as ASTM 6751 and EN 14214. Most of the determined fuel related properties of MOME fulfilled the minimum requirements of ASTM D6751 and EN 14214 biodiesel standards except oxidation stability. The stability of biodiesel is very critical and biodiesel requires antioxidant to meet storage requirements and to ensure fuel quality at all points along the distribution chain. Therefore, three antioxidants; 1, 2, 3 tri-hydroxy benzene (Pyrogallol, PY), 3, 4, 5-tri hydroxy benzoic acid (Propyl Gallate, PG) and 2-tert butyl-4-methoxy phenol (Butylated Hydroxyanisole, BHA) were investigated. The result showed that, PY and PG were more effective antioxidants than BHA.

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31

Zheng, Hua, Hong Zhang, Jin Gan, Ying Feng, and Wen Wen Zhang. "Technique of Spray-Drying on Phyllanthus emblica L. and Anti-Oxidation of the Product." Advanced Materials Research 524-527 (May 2012): 2321–24. http://dx.doi.org/10.4028/www.scientific.net/amr.524-527.2321.

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Phyllanthus emblica L. was abundant with Vc, SOD and other nutrients. In order to find a rapid and low loss way for its solid product, spray-drying was tested on its juice. According to orthogonal experiment, the best drying condition was selected as the concentration of 0.22g/mL, input temperature of 120°C and air velocity of 0.65m3/min. With the optimal drying, it was yielded the highest amount of powder at 57.4% and 52.6% of Vc in raw juice was maintained in the dried product. The final powder was still full of SOD and its inhibition rate to autoxidation velocity of pyrogallol was 29.6%. Color, particle size, flavor, taste and resolubility were well available to solid beverage requirment. It was indicated that the technique was efficient for the drying of P. emblica L. and the dried product was anti-oxidative to some extent.

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Bridi, Raquel, Ady Giordano, Maria Fernanda Peñailillo, and Gloria Montenegro. "Antioxidant Effect of Extracts from Native Chilean Plants on the Lipoperoxidation and Protein Oxidation of Bovine Muscle." Molecules 24, no. 18 (September 7, 2019): 3264. http://dx.doi.org/10.3390/molecules24183264.

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The present study investigated the antioxidant potential and the ability to inhibit lipid and protein oxidation in bovine meat of four native Chilean species: canelo (Drimys winteri), nalca (Gunnera tinctoria), tiaca (Caldcluvia paniculata), and ulmo (Eucryphia cordifolia). Phenolic acids (gallic, chlorogenic, caffeic, and coumaric) and flavonoids (catechin, epicatechin, and rutin) were identified and quantified by HPLC-MS/MS. Drimys winteri extract exhibited the highest antioxidant capacity evaluated by oxygen radical absorption capacity-red pyrogallol method (ORAC-PGR) and ferric ion reducing antioxidant power (FRAP) assays. All extracts decreased lipid oxidation induced by 2,2’-azo-bis(2-amidinopropane) dihydrochloride (AAPH) derived peroxyl radicals by anywhere between 30% and 50% the. In addition, canelo and nalca extracts decreased spontaneous oxidation by around 57% and 37% in relation to the control group, being even more efficient than butylated hydroxyanisole (BHT) a synthetic antioxidant. Protein oxidation in the myofibrillar proteins was evaluated by the formation of protein carbonyls and loss of protein thiols. The canelo, ulmo, and nalca extracts decreased the formation of carbonyls by around 30%. Plant extracts and BHT did not show an antioxidant effect on protein thiol loss. However, tiaca and ulmo extracts exerted a pro-oxidant effect, favoring the oxidation of sulfhydryl groups. The oxidizing system induced structural changes in myofibrillar protein (SDS−PAGE). A protective effect on protein structure from the canelo extract can be observed during the incubation when compared to samples incubated with AAPH.

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33

Chen, Jianchun, and Jun Bai. "Chemiluminescence flow sensor with immobilized reagent for the determination of pyrogallol based on potassium hexacyanoferrate(III) oxidation." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 71, no. 3 (December 2008): 989–92. http://dx.doi.org/10.1016/j.saa.2008.02.022.

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34

Shaliutina-Kolešová, A., N. Rui, S. Ashtiani, M. Rodina, J. Cosson, and O. Linhart. "Oxidative stress and antioxidant enzyme defence system in seminal plasma of common carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss) during spawning season." Czech Journal of Animal Science 63, No. 2 (January 21, 2018): 78–84. http://dx.doi.org/10.17221/89/2017-cjas.

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Assessment of seminal oxidative stress indicators is emerging as a valuable prognostic tool in assisted reproductive technology. We investigated levels of oxidative stress caused by reactive oxygen species (ROS) and the antioxidant enzyme defence system comprising superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxidase (GPx) in seminal plasma (SP) of common carp Cyprinus carpio and rainbow trout Oncorhynchus mykiss over the course of the spawning season. Oxidation was determined in lipids and proteins by assessing thiobarbituric acid reactive species (TBARS) and the 2,4-dinitrophenylhydrazine carbonyl groups, respectively. Levels of SOD were assessed by the autoxidation of pyrogallol. Determination of GR and GPx was based on the rate of NADPH oxidation. We observed clear alterations in lipids and proteins over the course of the spawning season in both species. The highest levels of TBARS and CP were recorded late in the season. SOD was not significantly altered in either species. The activity of GR was higher in carp SP late in spawning compared to other times (P < 0.05), while in rainbow trout, GR significantly increased (24.13 ± 2.8 mU/mg protein) in mid-season. A significantly lower GPx activity (9.18 ± 1.32 mU/mg protein) was found in rainbow trout SP early in the spawning season, but no significant differences in GPx were observed over the course of the season in carp. These results provide further understanding of the role of fish SP antioxidants and present new data on the oxidant and antioxidant balance in SP during the spawning season that may be of value in the development of methods for artificial reproduction of teleost species.

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Matsuo, Yosuke, Fumiya Tadakuma, Takuya Shii, Yoshinori Saito, and Takashi Tanaka. "Selective oxidation of pyrogallol-type catechins with unripe fruit homogenate of Citrus unshiu and structural revision of oolongtheanins." Tetrahedron 71, no. 17 (April 2015): 2540–48. http://dx.doi.org/10.1016/j.tet.2015.03.016.

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Atala, E., G. Velásquez, C. Vergara, C. Mardones, J. Reyes, R. A. Tapia, F. Quina, et al. "Mechanism of Pyrogallol Red Oxidation Induced by Free Radicals and Reactive Oxidant Species. A Kinetic and Spectroelectrochemistry Study." Journal of Physical Chemistry B 117, no. 17 (April 10, 2013): 4870–79. http://dx.doi.org/10.1021/jp400423w.

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37

Tsogas, George Z., Dimosthenis L. Giokas, Athanasios G. Vlessidis, and Nicholaos P. Evmiridis. "The effects of solvent preoxidation on inhibited chemiluminescence of pyrogallol oxidation in flow injection analysis and liquid chromatography." Analytica Chimica Acta 565, no. 1 (April 2006): 56–62. http://dx.doi.org/10.1016/j.aca.2006.02.018.

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38

Edens, William A., Tresa Q. Goins, David Dooley, and Joan M. Henson. "Purification and Characterization of a Secreted Laccase of Gaeumannomyces graminis var.tritici." Applied and Environmental Microbiology 65, no. 7 (July 1, 1999): 3071–74. http://dx.doi.org/10.1128/aem.65.7.3071-3074.1999.

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ABSTRACT We purified a secreted fungal laccase from filtrates ofGaeumannomyces graminis var. tritici cultures induced with copper and xylidine. The active protein had an apparent molecular mass of 190 kDa and yielded subunits with molecular masses of 60 kDa when denatured and deglycosylated. This laccase had a pI of 5.6 and an optimal pH of 4.5 with 2,6-dimethoxyphenol as its substrate. Like other, previously purified laccases, this one contained several copper atoms in each subunit, as determined by inductively coupled plasma spectroscopy. The active enzyme catalyzed the oxidation of 2,6-dimethoxyphenol (Km = 2.6 × 10−5 ± 7 × 10−6 M), catechol (Km = 2.5 × 10−4 ± 1 × 10−5 M), pyrogallol (Km = 3.1 × 10−4 ± 4 × 10−5 M), and guaiacol (Km = 5.1 × 10−4 ± 2 × 10−5 M). In addition, the laccase catalyzed the polymerization of 1,8-dihydroxynaphthalene, a natural fungal melanin precursor, into a high-molecular-weight melanin and catalyzed the oxidation, or decolorization, of the dye poly B-411, a lignin-like polymer. These findings indicate that this laccase may be involved in melanin polymerization in this phytopathogen’s hyphae and/or in lignin depolymerization in its infected plant host.

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Alves, Thayane Miranda, Cintia Megid Barbieri, Marco Aurelio Gomes, Heitor Ceolin Araujo, Nathália de Oliveira Visquette, Liliane Passanezi de Almeida Louzada, Cristina Antoniali Silva, Antonio Hernandes Chaves-Neto, and Ana Claudia de Melo Stevanato Nakamune. "Alteration on redox status in saliva of microcephaly children." Research, Society and Development 10, no. 7 (June 26, 2021): e40010716796. http://dx.doi.org/10.33448/rsd-v10i7.16796.

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Microcephaly is described as a reduction of the head circumference, due to the premature fusion of the bones of the skull, preventing the brain from growing normally and reaching its maximum development. This condition may result in neurological disorders, phonation and chewing dysfunction, dysphagia and risk of malnutrition. This alteration contributes to oral hygiene impairment, and continuous uses of the antipsychotic and anticonvulsant medication. Thus, the purpose of this study was to evaluate if microcephaly modified redox balance in saliva. Our hypothesis is that in the microcephalic patient's salivary oxidative stress is lower because of the increase in antioxidant defenses. The study included 13 patients with microcephaly (microcephalic group – MC) and 12 patients without neurological disorders (normocephalic group – NC), from zero to ten years old, no edentulous. Saliva was collected using a cotton wool swab, placing it on the child's mouth floor. After centrifugation, supernatants were fractionated and stored at -80 °C for analyses. Lipid oxidative was evaluated by TBARS methods, total antioxidant capacity by the ferric reducing ability (FRAP) assay, uric acid (UA) was quantified by modified Trinder reaction, and superoxide dismutase activity (SOD) by inhibition of the pyrogallol auto-oxidation. Total protein was measured using the method of Lowry. Compared to NC group, TBARS was significantly lower in MC group, while FRAP, UA and SOD were higher. Our hypothesis was confirmed. MC patients have lower salivary oxidative stress, due to increased oxidant defenses.

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Hu, Hui-Chao, Tong Zeng, Shaokai Zhang, Lihui Chen, Liulian Huang, and Yonghao Ni. "Determination of pinene content in black liquor by solvent-assisted/pyrogallol-protected headspace gas chromatography (HS-GC)." Holzforschung 72, no. 11 (November 27, 2018): 973–78. http://dx.doi.org/10.1515/hf-2018-0031.

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Abstract A solvent-assisted and pyrogallol (PG)-protected headspace gas chromatography (HS-GC) method was developed to determine the pinene (α- and β-pinene) content in the kraft pulping black liquor (BL). Ethanol (EtOH) addition eliminated pinene’s micelles in BL by complete dissolution in the EtOH/BL medium. PG was applied to protect pinene from oxidation during the sample storage and measurement. The results showed that, with a 25% (v/v) of EtOH content and a 0.1 g of PG in 5-ml of sample solution, a rapid and stable pinene HS extraction can be obtained in 20 min at 80°C. The method has high precision with relative standard deviations within 4.2%. The sensitivity [limits of quantification (LOQ) are ~140 μg l−1] was high, and a good accuracy (recovery=96.0–104%) was typical for the pinene detection. The presented method is simple, rapid, accurate and is suitable for pinene quantification in biorefinery related processes and it leads to the preparation of high-value chemicals.

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Mohamed Shameer, P., and P. Mohamed Nishath. "Investigation and enhancement on fuel stability characteristics of biodiesel dosed with various synthetic antioxidants." Energy & Environment 29, no. 7 (April 25, 2018): 1189–207. http://dx.doi.org/10.1177/0958305x18772415.

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Nearly 350 species of biodiesel feedstocks have been identified by many researchers for the past few decades. Unlike petroleum diesel, the biodiesel degrades rapidly and deterioration of its quality occurred while contacting with atmospheric oxygen. This main drawback of instability of fuel properties limited the commercial use of biodiesel in the global fuel market. To inhibit this oxidative degradation of biodiesel, the antioxidants are used. Comparing to other antioxidants, the synthetic antioxidants (phenolic) are more efficient. This study investigates the effects of commercially available and cheap synthetic antioxidants (TBHQ – tert-butylhydroxyquinone, PY – pyrogallol, PG – propyl gallate, BHT – butylated hydroxytoluene, and BHA – butylated hydroxyanisole) at 1000 ppm concentration on the fuel stability of Calophyllum inophyllum biodiesel. The discrepancy in antioxidant activity has been characterized using Fourier transform infrared spectroscopy by analyzing the O–H and C–H molecular chains prevalence in the infrared spectrum region of 3000–3700 cm−1 and 2800–3000 cm−1. TBHQ at 1000 ppm dosed with C. inophyllum biodiesel improves the oxidation stability by 42.56%, storage stability by 36.57%, and thermal stability by 41.02% when compared to those of pure biodiesel (B100) without any antioxidant. The rank of antioxidants effectiveness with pure biodiesel is obtained as TBHQ > PG > PY > BHT > BHA.

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Jain, Siddharth, and M. P. Sharma. "Oxidation, Thermal, and Storage Stability Studies of Jatropha Curcas Biodiesel." ISRN Renewable Energy 2012 (January 12, 2012): 1–15. http://dx.doi.org/10.5402/2012/861293.

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The present work reports the results of the study of the effect of metal contaminants on the oxidation, thermal, and storage stability of Jatropha curcas biodiesel (JCB) with and without antioxidants. Taking Pyrogallol (PY) as the most effective antioxidant based on the earlier work of the authors, JCB was mixed with different transition metals—Fe, Ni, Mn, Co, and Cu in different concentrations. Induction period (IP) was measured using Rancimat method (EN 14112). The ASTM D6468 and thermogravimetric analysis (TGA) methods are used for evaluating the thermal behavior of JCB. Based on results, several correlations are developed for assessing the oxidation, thermal, and storage stability. For the purpose of optimization, response surface methodology (RSM) is used. A comparison between the experimental values and those predicted by the correlation shows that all the data points lie within ±10% deviation lines of the experimental results. The optimized concentration of PY for 2 ppm metal-contaminated biodiesel to have an IP of 6 hr is 326.96, 361.64, 386.15, 417.24, and 600 ppm for Fe, Ni, Mn, Co, and Cu, respectively. From the experiments it is found that if metal concentration is 0, then, 200 ppm of PY is sufficient to make biodiesel stable for 6 months. If metal (Fe) concentration is 2 ppm or more, then 800 ppm PY is sufficient to make biodiesel stable for 5.5 months. This is the first study of its kind being reported in the literature in which RSM is used for design of experiment for developing the correlation for oxidation, thermal, and storage stability. The models developed by RSM will be highly useful for predicting the optimum antioxidant concentration to impart maximum fuel stability in JCB.

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Evmiridis, N. "Chemiluminescence (CL) emission generated during oxidation of pyrogallol and its application in analytical chemistry. I. Effect of oxidant compound." Talanta 46, no. 1 (May 1998): 179–96. http://dx.doi.org/10.1016/s0039-9140(97)00272-5.

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44

Thanasoulias, Nicholaos K., Athanasios Vlessidis, and Nicholaos P. Evmiridis. "Influence of oxidant-species scavengers on the chemiluminescence (CL) emission generated during the oxidation of pyrogallol by hydrogen peroxide." Analytica Chimica Acta 401, no. 1-2 (November 1999): 197–207. http://dx.doi.org/10.1016/s0003-2670(99)00478-x.

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45

Lau, Oi-Wah, and Shiu-Fai Luk. "Spectrophotometric Determination of Ascorbic Acid in Canned Fruit Juices, Cordials, and Soft Drinks with Iron(III) and 1,10-Phenanthroline as Reagents." Journal of AOAC INTERNATIONAL 70, no. 3 (May 1, 1987): 518–20. http://dx.doi.org/10.1093/jaoac/70.3.518.

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Abstract A simple and accurate spectrophotometric method has been developed for the determination of ascorbic acid in canned fruit juices, cordials, and soft drinks, based on the reduction of iron(III) by ascorbic acid to iron(II), which is then complexed with 1,10-phenanthroline. Background correction is necessary for most samples and can be achieved by copper(II)-catalyzed oxidation of the acid. The calibration graph was linear from 0 to 8 μg/mL of ascorbic acid with a slope of 0.12/ppm. The precision for the determination of ascorbic acid in a lemon drink containing 210 μg/mL of the acid was 0.9%. Many ingredients commonly found in fruit juices, cordials, and soft drinks do not interfere; however, tannic acid, pyrogallol, and sulfite interfere with the method. A wide range of samples was analyzed for ascorbic acid content by the proposed method. The samples included mango and lemon tea drinks and also grapefruit juices, for which no background correction is needed.

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46

Olson, Kenneth R., Yan Gao, and Karl D. Straub. "Oxidation of Hydrogen Sulfide by Quinones: How Polyphenols Initiate Their Cytoprotective Effects." International Journal of Molecular Sciences 22, no. 2 (January 19, 2021): 961. http://dx.doi.org/10.3390/ijms22020961.

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We have shown that autoxidized polyphenolic nutraceuticals oxidize H2S to polysulfides and thiosulfate and this may convey their cytoprotective effects. Polyphenol reactivity is largely attributed to the B ring, which is usually a form of hydroxyquinone (HQ). Here, we examine the effects of HQs on sulfur metabolism using H2S- and polysulfide-specific fluorophores (AzMC and SSP4, respectively) and thiosulfate sensitive silver nanoparticles (AgNP). In buffer, 1,4-dihydroxybenzene (1,4-DB), 1,4-benzoquinone (1,4-BQ), pyrogallol (PG) and gallic acid (GA) oxidized H2S to polysulfides and thiosulfate, whereas 1,2-DB, 1,3-DB, 1,2-dihydroxy,3,4-benzoquinone and shikimic acid did not. In addition, 1,4-DB, 1,4-BQ, PG and GA also increased polysulfide production in HEK293 cells. In buffer, H2S oxidation by 1,4-DB was oxygen-dependent, partially inhibited by tempol and trolox, and absorbance spectra were consistent with redox cycling between HQ autoxidation and H2S-mediated reduction. Neither 1,2-DB, 1,3-DB, 1,4-DB nor 1,4-BQ reduced polysulfides to H2S in either 21% or 0% oxygen. Epinephrine and norepinephrine also oxidized H2S to polysulfides and thiosulfate; dopamine and tyrosine were ineffective. Polyphenones were also examined, but only 2,5-dihydroxy- and 2,3,4-trihydroxybenzophenones oxidized H2S. These results show that H2S is readily oxidized by specific hydroxyquinones and quinones, most likely through the formation of a semiquinone radical intermediate derived from either reaction of oxygen with the reduced quinones, or from direct reaction between H2S and quinones. We propose that polysulfide production by these reactions contributes to the health-promoting benefits of polyphenolic nutraceuticals.

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MITIC, S. S., G. Z. MILETIC, and D. A. KOSTIC. "Kinetic Determination of Traces of Iodide by Its Catalytic Effect on Oxidation of Sodium Pyrogallol-5-sulfonate by Hydrogen Peroxide." Analytical Sciences 19, no. 6 (2003): 913–16. http://dx.doi.org/10.2116/analsci.19.913.

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Forteza, Rafael, José Manuel Estela, and Victor Cerdà. "Kinetic enthalpimetric determination of vanadium(V) by its catalytic effect on the oxidation rate of Pyrogallol Red by potassium bromate." Analyst 116, no. 11 (1991): 1171–73. http://dx.doi.org/10.1039/an9911601171.

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Ensafi, Ali A., and B. Rezaei. "Kinetic-Spectrophotometric Determination of Traces of Osmium by Its Catalytic Effect on the Oxidation of Pyrogallol Red by Hydrogen Peroxide." Analytical Letters 26, no. 8 (August 1993): 1771–85. http://dx.doi.org/10.1080/00032719308021495.

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Ensafi, A. A., and Z. Nazemi. "Determination of formaldehyde by its catalytic effect on the oxidation of pyrogallol red by bromate using flow-injection spectrophotometric detection." Journal of Analytical Chemistry 62, no. 10 (October 2007): 987–91. http://dx.doi.org/10.1134/s1061934807100152.

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