A critical review of methodologies used in determination of relative bio-availability ratio ofRRR-α-tocopheryl acetate andall-rac-α-tocopheryl acetate

Dersjant-Li, Y.; Peisker, M.

doi:10.1002/jsfa.3994

Cited by 10 publications

(11 citation statements)

References 62 publications

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“…Although four different tocopherols and four different tocotrienols (as alpha, beta, delta and gamma for both) are referred as ‘Vit E’, d‐alpha‐tocopherol is known to be the natural form with the highest bioavailability and biological activity. Synthetic Vit E derivatives like acetate and succinate which are often used as supplements are suggested to possess less bioavailability as compared to natural Vit E (Dersjant‐Li & Peisker, ). In our study, synthetic esterified form of Vit E as dl‐alpha‐tocopheryl acetate is used because ester forms are known to be more resistant to oxidation.…”

Section: Discussionmentioning

confidence: 99%

Carnosine and vitamin E - a promising pair in the combat against testicular oxidative stress in aged rats

et al. 2014

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Oxidative stress is considered to play a key role in ageing. Carnosine alone or together with vitamin E may prove to be helpful in dealing with problems of ageing through its antioxidant activity. Testis, by producing steroids and possessing a poor antioxidant system may become a strong target for the chronic oxidative stress generated during ageing. Therefore we investigated the in vivo effect of carnosine alone or together with vitamin E on testicular oxidative stress in aged rats. In this study, young (5 months) and aged (22 months) Wistar rats were used. Carnosine (250 mg kg(-1); i.p.; 5 days per week) and vitamin E (200 mg kg(-1); i.m.; twice per week) were given to aged rats for 2 months. Increased testicular lipid peroxidation and superoxide dismutase activity in aged rats were declined to the levels of young ones by both treatments. Decreased glutathione peroxidase and glutathione transferase activities returned to the level of young's only by carnosine plus vitamin E treatment. Histopathological evaluation described by Johnsen's score, also showed significant improvement with preserved spermatogenesis. Carnosine plus vitamin E treatment appears to stage a powerful performance by attenuating testicular oxidative stress and sparing the antioxidant system.

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Section: Discussionmentioning

confidence: 99%

Carnosine and vitamin E - a promising pair in the combat against testicular oxidative stress in aged rats

et al. 2014

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“…A study evaluating plasma concentration and distribution of α-tocopherol stereoisomers after intramuscular injection of 2.5 g all-rac α-tocopheryl acetate [19] evidenced difference in turnover rate of different stereoisomers in cow plasma: the 2S stereoisomers had showed the faster disappearance from blood compared to the other forms; however, considering the plasma concentration of stereoisomers one day after injection, the 2S forms showed also a faster increase related to their initial level, when compared to the other forms. Based on plasma concentrations at 10 days after injection, Dersjant-Li and Peisker [20] calculated a higher relative bioavailability of RRR α-tocopheryl acetate over all-rac α-tocopheryl acetate. However, considering that plasma distribution of stereoisomers is different over time, sampling time (e.g.…”

Section: Natural Versus Synthetic Vitamin Ementioning

confidence: 99%

“…Methodologies used in the evaluation of α-tocopherol forms bioavailability frequently diverge according to different studies, making it difficult to compare sometimes dissimilar results [20]. To estimate true relative bioavailability of RRR over all-rac α-tocopheryl acetate, it is also important to consider the contribution given by α-tocopherol originating from basal ingredients, consisting only of RRR form and responsible for the basal plasma level.…”

Section: Natural Versus Synthetic Vitamin Ementioning

confidence: 99%

Vitamin E Bioavailability: Past and Present Insights

Vagni¹,

Saccone²,

Pinotti³

et al. 2011

FNS

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Over the past decades several studies have investigated the importance of an adequate vitamin E status to sustain both animal health and production in dairy cows. Cow milk is considered as a remarkable source of bioactive components promoting human health, which has renewed interest in the effects of vitamin E supplementation on its nutritional value, sensory quality and shelf life. Thus, defining relative bioavailability, utilisation and transfer into milk of different vitamin E formulations is particularly important to assess the adequate levels of supplementation for animal health and milk quality. In nature vitamin E is present under one isomeric form, RRR α-tocopherol; when α-tocopherol is synthesized chemically, a racemic mixture of 8 possible isomers of α-tocopherol in equimolar concentrations is produced (all-rac α-tocopherol). The different stereoisomers have different biopotencies in humans and livestock; the conversion factor between RRR and all-rac vitamin E was estimated by early studies on the basis of the rat foetal resorption bioassay, and then extended to other species. Recent advances on the distribution of vitamin E stereoisomers in plasma and tissues have highlighted the need to formulate new conversion factors in dairy cows as well as in humans. On account of this, the present article aims to consider past and recent data related to vitamin E in dairy cow nutrition

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“…All tocopherol isoforms possess three chiral centers, so, in principle, eight diastereoisomers can be synthetically obtained and are widely used in animal nutrition [12] as well as in cosmetic products [13]. Currently, the tocopherol manufacturing implies the production of about 35,000 tons of racemic mixture per year [14].…”

Section: Introductionmentioning

confidence: 99%

“…Currently, the tocopherol manufacturing implies the production of about 35,000 tons of racemic mixture per year [14]. The highest bioavailability is associated to the naturally occurring RRR -diastereoisomer of -T [12], [15].…”

Section: Introductionmentioning

confidence: 99%

Engineering Tocopherol Selectivity in α-TTP: A Combined In Vitro/In Silico Study

et al. 2012

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We present a combined in vitro/in silico study to determine the molecular origin of the selectivity of -tocopherol transfer protein (-TTP) towards -tocopherol. Molecular dynamics simulations combined to free energy perturbation calculations predict a binding free energy for -tocopherol to -TTP 8.262.13 kcal mol lower than that of -tocopherol. Our calculations show that -tocopherol binds to -TTP in a significantly distorted geometry as compared to that of the natural ligand. Variations in the hydration of the binding pocket and in the protein structure are found as well. We propose a mutation, A156L, which significantly modifies the selectivity properties of -TTP towards the two tocopherols. In particular, our simulations predict that A156L binds preferentially to -tocopherol, with striking structural similarities to the wild-type--tocopherol complex. The affinity properties are confirmed by differential scanning fluorimetry as well as in vitro competitive binding assays. Our data indicate that residue A156 is at a critical position for determination of the selectivity of -TTP. The engineering of TTP mutants with modulating binding properties can have potential impact at industrial level for easier purification of single tocopherols from vitamin E mixtures coming from natural oils or synthetic processes. Moreover, the identification of a -tocopherol selective TTP offers the possibility to challenge the hypotheses for the evolutionary development of a mechanism for -tocopherol selection in omnivorous animals.

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A critical review of methodologies used in determination of relative bio-availability ratio ofRRR-α-tocopheryl acetate andall-rac-α-tocopheryl acetate

Cited by 10 publications

References 62 publications

Carnosine and vitamin E - a promising pair in the combat against testicular oxidative stress in aged rats

Carnosine and vitamin E - a promising pair in the combat against testicular oxidative stress in aged rats

Vitamin E Bioavailability: Past and Present Insights

Engineering Tocopherol Selectivity in α-TTP: A Combined In Vitro/In Silico Study

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