Kinetics and Dynamics of Singlet Oxygen Scavenging by α-Tocopherol in Phospholipid Model Membranes

Fukuzawa, Kenji; Matsuura, Kayo; Tokumura, Akira; Suzuki, Asahi; Terao, Junji

doi:10.1016/s0891-5849(96)00485-6

Cited by 67 publications

(54 citation statements)

References 26 publications

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“…We calculated their membranous second-order rate constant (ks) assuming that all antioxidant molecules were located in EYPC membranes and using the estimation that their concentration in EYPC membranes (mol of Toc-3H or TocH/L of EYPC) was 133 times higher in the bulk MeOH/H2O phase (13). The ks values of Toc-3H and TocH homologues obtained in EYPC membrane and in EtOH solution are summarized in Table 1.…”

Section: Resultsmentioning

confidence: 99%

A Kinetic Study of the Radical-Scavenging Action of Tocotrienols in the Membranes of Egg Yolk Phosphatidylcholine Vesicles

Fukuzawa

Ouchi

Nagaoka

et al. 2014

J Nutr Sci Vitaminol

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Vitamin E is a generic term for all tocopherol (TocH) and tocotrienol (Toc-3H) homologues. The antioxidant effect of vitamin E has been ascribed to the oxidation of its phenolic hydroxyl group by lipid peroxyl radicals (LOO·), producing corresponding tocopheroxyl radicals (Toc·) or tocotrienoxy radicals (Toc-3·) (reaction 1). The mechanism involved has been studied extensively by several investigators (1-5).It is well known that lipophilic vitamin E is localized in biomembranes and functions as an efficient inhibitor of lipid peroxidation in membranes (6-10). We recently reported the second-order rate constants (ks) for the reactions of a-, b-, g-, d-TocH, and tocol with the 2,6-dit-butyl-4-(4-methoxyphenyl)phenoxyl radical (ArO·), which can be regarded as a model for lipid peroxyl radicals (LOO·), in membranes (reaction 2) using stoppedflow spectrophotometry (10).In this experiment, we used samples of egg yolk phosphatidylcholine (EYPC) vesicles as a membrane model in a 70% methanol solution with low turbidity, which is suitable for measuring by spectrophotometry. In the present work, we measured ks values in EYPC membranes for the reactions of a-, b-, g-, and d-Toc-3Hs with the ArO· radical.

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Section: Resultsmentioning

confidence: 99%

A Kinetic Study of the Radical-Scavenging Action of Tocotrienols in the Membranes of Egg Yolk Phosphatidylcholine Vesicles

Fukuzawa

Ouchi

Nagaoka

et al. 2014

J Nutr Sci Vitaminol

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“…A close correlation was indeed observed between the increase of the peak intensity of PPF fluorescence and the increasing amount of preformed liposomes. [38,39]. These values are (1.35 T 0.05) Â 10 7 M À1 s À1 for DP, which is embedded within the liposomes [31], and (0.8 T 0.04) Â 10 7 M À1 s À1 for the aqueous dye, UP [29,30].…”

Section: Discussionmentioning

confidence: 97%

Reactivity towards singlet oxygen of propofol inside liposomes and neuronal cells

Heyne

Brault²,

Fontaine‐Aupart

et al. 2005

Biochimica et Biophysica Acta (BBA) - General Subjects

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Singlet oxygen ( 1 O 2 ), a reactive oxygen species, has been found to be implicated in many cellular events and pathological disorders. Herein, we investigated the reactivity of 1 O 2 towards the anaesthetic agent propofol (PPF) encapsulated within DMPC liposomes. By time resolved luminescence, the rate constant of 1 O 2 quenching by PPF was evaluated, depending on the location of the sensitizer, with following values: 1.35 T 0.05 Â 10 7 M À1 s À1 for deuteroporphyrin (as embedded source) and 0.8 T 0.04 Â 10 7 M À1 s À1 for uroporphyrin (as external source), respectively. The nature of the oxidation product, resulting from the reaction of 1 O 2 with PPF, was determined using absorption and HPLC techniques. Finally, the in vitro protective effect of PPF towards the 1 O 2 -induced neuronal cell toxicity was evaluated in terms of cell viability. D

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“…Most of these studies were carried out in homogeneous solvent systems (i.e. either aqueous or lipid) (Niki et al 1984 ) or artifi cial membranes (liposomes, micelles) in buffer solutions (Fukuzawa et al 1997, Woodall et al 1995, or by using isolated LDLs (Carroll et al 2000 ), cells (Palozza et al 2004 ), and tissue preparations (Palozza and Krinsky 1992b ). However, these types of model systems are far different from an actual biological system such as human serum/plasma, in that plasma is a heterogeneous entity consisting of hydrophilic and lipophilic compartments and contains high concentrations of other components such as protein ( ∼ 600 μ mol/L).…”

Section: Biological Significance Of Antioxidant Interactionsmentioning

confidence: 99%

Antioxidant Activity and Oxidative Stress: An Overview

Yeum

Russell

Aldini

2010

Biomarkers for Antioxidant Defense and Oxidative Damage: Principles and Practical Applications

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Kinetics and Dynamics of Singlet Oxygen Scavenging by α-Tocopherol in Phospholipid Model Membranes

Cited by 67 publications

References 26 publications

A Kinetic Study of the Radical-Scavenging Action of Tocotrienols in the Membranes of Egg Yolk Phosphatidylcholine Vesicles

A Kinetic Study of the Radical-Scavenging Action of Tocotrienols in the Membranes of Egg Yolk Phosphatidylcholine Vesicles

Reactivity towards singlet oxygen of propofol inside liposomes and neuronal cells

Antioxidant Activity and Oxidative Stress: An Overview

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