Investigation of γ-irradiation of α-tocopherol and its related derivatives by high-performance liquid chromatography using a rapid scanning spectrophotometer

Molnár, Imre; Koswig, Susanne

doi:10.1016/0021-9673(92)85027-q

Cited by 5 publications

(3 citation statements)

References 31 publications

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“…Several authors report the formation of formyl derivatives from I during the autoxidation of vitamin E (Fujimaki et al, 1970 and, after irradiation with γ-rays in two different solvents, n-hexane and CHCl 3 (Molnar et al, 1992).…”

Section: Resultsmentioning

confidence: 99%

“…Its reactivity and that of some of its model compounds toward chemical oxidants have also been reported (Suarna et al, 1988). The influence of other physical factors on I, such as γ-rays, was studied by several authors (Knapp and Tappel, 1961;Jore and Ferradini, 1985;Molnar and Koswig, 1992). Surprisingly, data on the photolysis of I under domestic conditions (room temperature, sunlight) are not reported in the literature, although some foodstuffs (e.g., oils) could easily be injured by light.…”

Section: Introductionmentioning

confidence: 99%

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Photolysis of α-Tocopherol in Olive Oils and Model Systems

Pirisi¹,

Angioni²,

Bandino³

et al. 1998

J. Agric. Food Chem.

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The photolysis of α-tocopherol (I) in olive oil (O) and in some model systems (n-hexane = H; anhydrous n-hexane = HA, and triolein = T) was studied under sunlight and under artificial light (λ > 290 nm) by HPLC and GC/MS. In O and T, I disappeared linearly to 50% of the starting concentration, reached a constant value, and finally disappeared rapidly from the medium. In the model system, photolysis followed a pseudo-first-order kinetics. Although no peaks attributable to photoproducts were found in O, a main product identified by 1H and 13C NMR and GC/MS as 5-formyltocopherol (II) was found in the model systems. Irradiation of compound II led to species undetectable by HPLC in agreement with a slower consecutive kinetic process than that of I. In the HA and T systems, the formation of II occurred at lower levels than in H. The possible behavior of photodegradation is discussed. Keywords: α-Tocopherol; photolysis; olive oil

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Photolysis of α-Tocopherol in Olive Oils and Model Systems

Pirisi¹,

Angioni²,

Bandino³

et al. 1998

J. Agric. Food Chem.

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“…Nogala-Kalucka and Goglewski [12] recently examined dimers of a-tocopherol and y-toco-(5) pherol in heated plant oil by TLC. Formation of tocopherolquinone and the epoxides were studied in model reactions by oxidation with singlet oxygen [4,[13][14][15][16] after y-irradiation [17] and in biological systems [7, 9, 181. In this study degradation products of a-tocopherol were positively identified and quantified in heated plant oil. Besides a-tocopherolquinone, which is available as a standard material, the two a-tocopherolepoxides ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Formation of α‐Tocopherolquinone and α‐Tocopherolquinone Epoxides in Plant Oil

1997

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The antioxidative activity of α‐tocopherol in oil is necessary for the inhibition of lipid peroxidation. If no regeneration of antioxidants is possible in foods, oxidation products are formed to a measurable extent. The aim of this study was to investigate oxidation products of α‐tocopherol in plant oil. The oxidation of α‐tocopherol in plant oil leads to α‐tocopherolquinone and to two epoxides (α‐tocopherolquinone‐2,3‐epoxide, α‐tocopherolquinone‐5,6‐epoxide). These three reaction products were identified and quantified in plant oil. The 2,3‐epoxide is formed at lower temperatures (90°C) whereas at high temperatures (180–220°C) only the 5,6‐epoxide appears. The kinetics show that the 5,6‐epoxide is produced as long as α‐tocopherol is present. With longer reaction times the concentration of the 5,6‐epoxide starts to decrease. α‐Tocopherolquinone is found at substantially lower concentrations.

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Separation of α-tocotrienol oxidation products and eight tocochromanols by HPLC with DAD and fluorescence detection and identification of unknown peaks by DAD, PBI-EIMS, FTIR, and NMR

Büsing

Ternes

2011

Anal Bioanal Chem

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Tocotrienols, like tocopherols, are members of the vitamin E family. While tocopherols (T) have been studied intensively, only recently have tocotrienols (T3) received increased attention due to their special health benefits. However, these positive attributes of T3 are probably lost as a result of degradation during food storage and processing, and there is little information about their oxidation products. Of particular interest are the oxidation products of α-tocotrienol (α-T3) as this is the least thermostable T3 isomer with the highest rate of degradation. The objective of this study was therefore to develop a reliable method for the determination of the most important oxidation products of α-T3 along with other tocochromanol isomers. We developed a high-performance liquid chromatography method with diode array detection, fluorescence detection, and a particle beam interface electron impact mass spectroscopy in order to separate the most important oxidation products of α-T3 (α-T3 spirodimers/spirotrimers, α-tocotrienoldihydroxy dimer, 7-formyl-β-tocotrienol (7-FβT3), 5-formyl-γ-tocotrienol (5-FγT3), α-tocotrienolquinone (α-T3Q), and α-T3Q dimers and α-tocotrienolquinone epoxides (α-T3QE)) from eight tocochromanol isomers. Furthermore, we sought to identify the as yet unknown oxidation products 5-FγT3, 7-FβT3, α-T3Q-dimer, and α-T3QE. Of these, 5-FγT3 was fully characterized by Fourier transform infrared spectroscopy and (1)H and (13)C nuclear magnetic resonance spectroscopy.

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Investigation of γ-irradiation of α-tocopherol and its related derivatives by high-performance liquid chromatography using a rapid scanning spectrophotometer

Cited by 5 publications

References 31 publications

Photolysis of α-Tocopherol in Olive Oils and Model Systems

Photolysis of α-Tocopherol in Olive Oils and Model Systems

Formation of α‐Tocopherolquinone and α‐Tocopherolquinone Epoxides in Plant Oil

Separation of α-tocotrienol oxidation products and eight tocochromanols by HPLC with DAD and fluorescence detection and identification of unknown peaks by DAD, PBI-EIMS, FTIR, and NMR

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