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Your search keyword '"Marković, Zoran"' showing total 11 results
Start Over Author "Marković, Zoran" Journal food chemistry
11 results on '"Marković, Zoran"'

10. Antiradical activity of delphinidin, pelargonidin and malvin towards hydroxyl and nitric oxide radicals: The energy requirements calculations as a prediction of the possible antiradical mechanisms

Author

Dimitrić-Marković, Jasmina, Pejin, Boris, Milenković, Dejan, Amic, Dragan, Begović, Nebojša, Mojović, Miloš, Marković, Zoran S., Dimitrić-Marković, Jasmina, Pejin, Boris, Milenković, Dejan, Amic, Dragan, Begović, Nebojša, Mojović, Miloš, and Marković, Zoran S.

Abstract

Naturally occurring flavonoids, delphinidin, pelargonidin and malvin, were investigated experimentally and theoretically for their ability to scavenge hydroxyl and nitric oxide radicals. Electron spin resonance (ESR) spectroscopy was used to determine antiradical activity of the selected compounds and M05-2X/6-311+G(d,p) level of theory for the calculation of reaction enthalpies related to three possible mechanisms of free radical scavenging activity, namely HAT, SET-PT and SPLET. The results obtained show that the molecules investigated reacted with hydroxyl radical via both HAT and SPLET in the solvents investigated. These results point to HAT as implausible for the reaction with nitric oxide radical in all the solvents investigated. SET-PT also proved to be thermodynamically unfavourable for all three molecules in the solvents considered.

Published
2017

11. Free radical scavenging activity of morin 2′-O− phenoxide anion

Author

Marković, Zoran, Milenković, Dejan, Đorović, Jelena, Dimitrić Marković, Jasmina M., Stepanić, Višnja, Lučić, Bono, and Amić, Dragan

Subjects
*FREE radicals, *PHENOXIDES, *MORIN, *ATOM transfer reactions, *SOLUTION (Chemistry), *THERMODYNAMICS
Abstract

Abstract: Due to intramolecular H-atom transfer, deprotonation of the most acidic 3-OH group of morin yields 2′-O− phenoxide anion. The reaction enthalpies related to mechanisms of free radical scavenging activity of this dominant species at a physiological pH of 7.4 were calculated by PM6 and DFT methods in gas-phase, water, benzene and DMSO. Results indicate the 4′-OH group of 2′-O− phenoxide anion is the active site for radical inactivation. The thermodynamically favoured mechanism depends on the polarity of the reaction media: in polar solvents (water and DMSO), the sequential proton loss electron transfer (SPLET) mechanism is preferred while in non-polar benzene (and in gas-phase), the hydrogen atom transfer (HAT) mechanism is responsible for the free radical scavenging activity of the morin phenoxide anion. Results show that the fast, semiempirical PM6 method fairly mimics more accurate, though time-consuming DFT methodologies. [Copyright &y& Elsevier]

Published
2012
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