Physico-chemical principles of antioxidant action, including solvent and matrix dependence and interfacial phenomena

Jodko-Piórecka, Katarzyna; Cędrowski, Jakub; Litwinienko, Grzegorz

doi:10.1002/9781119135388.ch12

Cited by 13 publications

(28 citation statements)

References 118 publications

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“…All experiments were performed by measuring the oxygen pressure changes in the two-channel gas uptake apparatus based on an ultra-precise differential pressure sensor (pressure transducer) described elsewhere [24,25]. Progress of oxidation was monitored by the measurement of the oxygen pressure difference between the reference (total solution volume~4 mL) and sample flask (total solution volume~4 mL)-in the sample flask, the oxygen was consumed in the presence of investigated compound (20 µL of 1-2 mM antioxidant solution in acetonitrile was added), in contrast to the reference flask with high concentration (250 µM) of PMHC (1c) in order to completely inhibit the oxidation process.…”

Section: Methodology Of Autoxidation Measurementsmentioning

confidence: 99%

Synthesis, DFT Calculations, and In Vitro Antioxidant Study on Novel Carba-Analogs of Vitamin E

et al. 2019

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Vitamin E is the most active natural lipophilic antioxidant with a broad spectrum of biological activity. α-Tocopherol (α-T), the main representative of the vitamin E family, is a strong inhibitor of lipid peroxidation as a chain-breaking antioxidant. Antioxidant and antiradical properties of vitamin E result from the presence of a phenolic hydroxyl group at the C-6 position. Due to stereoelectronic effects in the dihydropyranyl ring, the dissociation enthalpy for phenolic O–H bond (BDEOH) is reduced. The high chain-breaking reactivity of α-T is mainly attributed to orbital overlapping of the 2p-type lone pair on the oxygen atom (O1) in para position to the phenolic group, and the aromatic π-electron system. The influence of the O1 atom on the antioxidant activity of vitamin E was estimated quantitatively. The all-rac-1-carba-α-tocopherol was synthesized for the first time. Along with model compounds, 1-carba-analog of Trolox and its methyl ester were screened for their in vitro antioxidant activity by inhibition of styrene oxidation, and for the radical-reducing properties by means of 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH) scavenging assay. To study the antioxidant activity, density functional theory (DFT) was also applied. Reaction enthalpies related to HAT (hydrogen atom transfer), SET–PT (sequential electron transfer—proton transfer), and SPLET (sequential proton loss—electron transfer) mechanisms were calculated.

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Section: Methodology Of Autoxidation Measurementsmentioning

confidence: 99%

Synthesis, DFT Calculations, and In Vitro Antioxidant Study on Novel Carba-Analogs of Vitamin E

et al. 2019

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“…The antioxidant behavior of nanoparticles was evaluated by monitoring the rate of peroxidation in homogeneous and heterogeneous model systems. For homogeneous systems, the oxygen uptake was followed by pressure transducer apparatus described elsewhere [41][42][43]. Twin 10 mL vessels (a working vessel and reference one) connected to the ultra-sensitive membrane were immersed in a 30 • C water bath.…”

Section: Methodology Of Autoxidation Measurementsmentioning

confidence: 99%

“…During the oxidation course, the solution of examined compound was injected into the working vessel to reach the final concentration 2.5-5 µM, while in the reference vessel, 250 µM PMHC was still present in order to completely suppress the peroxidation process (thus, in both vessels, the evolution of N 2 from AIBN decomposition was compensated). For heterogeneous systems (micelles and liposomes), the uptake of dissolved oxygen during peroxidation was carried out at 37 • C by using a Biological Oxygen Monitor (Yellow Springs Instruments, Yellow Springs, OH, USA) equipped with a Clark-type electrode in the same way as described in one of our previous papers [42,44]. The samples were buffered at pH 4.0 and pH 7.0 with acetate and phosphate buffer, respectively.…”

Section: Methodology Of Autoxidation Measurementsmentioning

confidence: 99%

“…The amounts of added compounds were adjusted to reach 1 µM concentration of antioxidant (basing on TG results, 0.82 ppm 1B gives 1 µM concentration of chromanol residues in the sample), or 0.516 µM Au (corresponding to 0.1 ppm Au) for commercial Au nanoparticles stabilized with citrate. The length of inhibition was determined graphically [42]. The methods for calculation of the rate of initiation, rate of constants for inhibition, stoichiometric coefficient, and other details are described in Section 3.2.…”

Section: Methodology Of Autoxidation Measurementsmentioning

confidence: 99%

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Antioxidant Activity of Metal Nanoparticles Coated with Tocopherol-Like Residues—The Importance of Studies in Homo- and Heterogeneous Systems

2019

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Functionalized nanoparticles (NPs) attract great attention in pharmacy, diagnostics, and biomedical areas due to benefits like localization and unique interactions of NPs with biocomponents of living cells. In the present paper, we prepared and characterized two kinds of gold nanoparticles (AuNPs) coated with α-tocopherol-like residues: 1A were soluble in non-polar solvents and their antioxidant activity was tested during the peroxidation of a model hydrocarbon in a homogeneous system, whereas nanoparticles 1B were soluble in polar solvents and were applied as antioxidants in micellar and liposomal systems. The effectiveness of 1A is comparable to 2,2,5,7,8-pentamethylchroman-6-ol (PMHC, an analogue of α-tocopherol). Taking the results of the kinetic measurements, we calculated an average number of 2150 chromanol residues per one NP, suggesting a thick organic coating around the metal core. In heterogeneous systems, the peroxidation of methyl linoleate dispersed in Triton X-100 micelles or DMPC liposomes resulted in the observation that 1B (545 chromanol residues per one NP) was active enough to effectively inhibit peroxidation in a micellar system, but in a liposomal system, 1B behaved as a retardant (no clear induction period). The importance of microenvironment in heterogeneous systems on the overall antioxidant activity of nanoparticles is discussed.

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“…The autoxidation of polyunsaturated fatty acids has received much attention due to its involvement in food spoilage and because of its relevance in vivo to membrane damage and in various diseases. The kinetics and basic mechanism of the reaction in bulk solution is fairly well known but, in spite of the thousands of publications on the topic, some aspects are still a matter of debate [ 40 , 41 , 42 ]. Here, we will just provide a brief background and will show the most important kinetic equations.…”

Section: Lipid Intake: Health and Nutritional Aspectsmentioning

confidence: 99%

Polyphenolic Antioxidants in Lipid Emulsions: Partitioning Effects and Interfacial Phenomena

Losada‐Barreiro

Paiva‐Martins

2021

Foods

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The autoxidation of lipids in complex systems such as emulsions or biological membranes, although known to occur readily and to be associated with important pathological events, is lacking in quantitative data in spite of the huge efforts that have been made in attempting to unravel the complex mechanisms of lipid oxidation and its inhibition by antioxidants. Lipids are present as oil-in-water emulsions in many foods and pharmaceutical formulations, and the prevalent role of the interfacial region is critical to understand the antioxidant behavior and to correctly interpret antioxidant efficiencies. The aim of this review is to summarize the current knowledge on the chemical fate of antioxidants before they react with peroxyl radicals. Many researchers highlighted the predominant role of interfaces, and although some attempts have been made to understand their role, in most instances, they were essentially qualitative and based on putative hypotheses. It is only recently that quantitative reports have been published. Indeed, knowledge on the effects of relevant experimental variables on the effective concentrations of antioxidants is necessary for a successful design of alternate, effective antioxidative solutions.

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Physico-chemical principles of antioxidant action, including solvent and matrix dependence and interfacial phenomena

Cited by 13 publications

References 118 publications

Synthesis, DFT Calculations, and In Vitro Antioxidant Study on Novel Carba-Analogs of Vitamin E

Synthesis, DFT Calculations, and In Vitro Antioxidant Study on Novel Carba-Analogs of Vitamin E

Antioxidant Activity of Metal Nanoparticles Coated with Tocopherol-Like Residues—The Importance of Studies in Homo- and Heterogeneous Systems

Polyphenolic Antioxidants in Lipid Emulsions: Partitioning Effects and Interfacial Phenomena

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