Bond Dissociation Enthalpy of .alpha.-Tocopherol and Other Phenolic Antioxidants

Lucarini, Marco; Pedulli, Gian Franco; Cipollone, Marta

doi:10.1021/jo00096a061

Cited by 193 publications

(184 citation statements)

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“…This observation has previously been attributed to the unfavorable kinetic properties of highly hindered phenols. [16] The results for 5 and 1 reflect the known potency of catechols for the trapping of OH radicals and are a consequence of the lower BDE of 5 that results from stabilization of the phenoxyl radical through its involvment in an H-bond with the adjacent OH group. [15,17] The protective effects measured for compounds 6±11 (Figure 3 B and C) highlight the major determinants of the radicalscavenging capability of flavones and flavonols.…”

Section: High-throughput Screening Developmentmentioning

confidence: 66%

A Powerful Antiradiation Compound Revealed by a New High‐Throughput Screening Method

et al. 2004

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We present a new high-throughput screening method for the selection of powerful water-soluble antiradiation compounds. This method, which uses conventional immunoassay techniques, allowed the capacity of a given compound to protect thymidine from irradiation to be evaluated. By applying this assay to an antioxidant library, we showed for the first time that norbadione A, a well-known mushroom pigment, has pronounced atypical antiradiation properties.

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Section: High-throughput Screening Developmentmentioning

confidence: 66%

A Powerful Antiradiation Compound Revealed by a New High‐Throughput Screening Method

et al. 2004

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“…Such an equilibrium can bе attained only when both radicals are stable and do not enter the recombination reaction. In this case the equilibrium concentrations оf both radicals can bе determined bу electron paramagnetic resonance spectroscopy or spectrophotometrically (Mahoney & DaRooge, 1975;Belyakov at al., 1975, Lucarini at al., 1994. The equilibrium constant (K) is calculated from the ratio of the equilibrium concentrations of the molecules and radicals:…”

Section: Chemical Equilibrium (Ce)mentioning

confidence: 99%

“…This can bе attained bу carrying out experiments in no polar solvents. As the reference phenoxyl radical Ar l O • were used 2,4,6-tri-tert-butylphenoxyl ( (Mahoney & DaRooge, 1975;Lucarini at al., 1994), galvinoxyl (Belyakov at al., 1975), and ionol (Lucarini et al, 2002). Calculations of the equilibrium constant K from the reactant concentration ratio were followed bу calculations of the Gibbs free energy of equilibrium:…”

Section: Chemical Equilibrium (Ce)mentioning

confidence: 99%

“…Having determined the equilibrium constant, it is possible to estimate the O−H bond strength difference between two phenols. (Lucarini at al., 1994). When equilibrium between Ar i O • and Ar 1 OH was studied in the solvent (S) that forms hydrogen bond with phenol, the difference in hydrogen bond enthalpies was taken into account.…”

Section: Chemical Equilibrium (Ce)mentioning

confidence: 99%

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Dissociation Energies of O−H Bonds of Phenols and Hydroperoxides

Evgeny¹,

Taisa²

2011

Application of Thermodynamics to Biological and Materials Science

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“…(8)], thereby increasing its efficiency in terminating PEUU oxidation. 13,14 V⅐ + ROO⅐ → Nonradical products (Fast) (6) V⅐ + O 2 → Radical products (Slow)…”

Section: Antioxidant Mechanismsmentioning

confidence: 99%

Comparison of two antioxidants for poly(etherurethane urea) in an acceleratedin vitro biodegradation system

Schubert

Wiggins

Anderson

et al. 1997

J. Biomed. Mater. Res.

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Vitamin E (+/-alpha-tocopherol) was recently investigated as an antioxidant for implanted poly(etherurethane urea) (PEUU) elastomers. In that work, vitamin E prevented chemical degradation of biaxially strained PEUU up to 5 weeks implantation, and prevented pitting and cracking of the PEUU surface for the duration of the 10-week cage implant study. The promising results of the in vivo studies motivated a detailed comparison of vitamin E with Santowhite, the standard antioxidant used in PEUU elastomers. To evaluate vitamin E and Santowhite as antioxidants in PEUU, an accelerated in vitro treatment system was used that mimics the in vivo degradation of PEUUs. Vitamin E was even more effective than Santowhite in preventing pitting and cracking to the biaxially strained PEUU elastomers. The inhibition of ether oxidation was greater with vitamin E than with Santowhite when compared by equivalent concentrations and molar concentrations, respectively. It is hypothesized that the increased effectiveness of vitamin E in this system, compared to Santowhite, is due to differences in antioxidant mechanism(s). Vitamin E is more efficient in preventing PEUU oxidation than Santowhite because its phenoxy radical is more stable and it can terminate more than one chain per vitamin E molecule.

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Bond Dissociation Enthalpy of .alpha.-Tocopherol and Other Phenolic Antioxidants

Cited by 193 publications

References 0 publications

A Powerful Antiradiation Compound Revealed by a New High‐Throughput Screening Method

A Powerful Antiradiation Compound Revealed by a New High‐Throughput Screening Method

Dissociation Energies of O−H Bonds of Phenols and Hydroperoxides

Comparison of two antioxidants for poly(etherurethane urea) in an acceleratedin vitro biodegradation system

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