Physical and Chemical Determination of Vitamin A

Wilkie, J. B.

doi:10.1021/i560092a001

Cited by 8 publications

(2 citation statements)

References 34 publications

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“…Indeed, Wilkie extracted vitamin A using chloroform (ε = 4.7113) and diethyl ether (ε = 4.2400) as solvents. 34 In this experiment, the latter was found to have an appreciably higher absorption value than the former. Thus, in the actual study, diethyl ether (DEE) was evidently chosen to evaluate the influence of solvent on thermochemical properties including BDE.…”

Section: ■ Results and Discussionmentioning

confidence: 55%

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Is Vitamin A an Antioxidant or a Pro-oxidant?

et al. 2017

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Antioxidant efficiency of all-trans-retinol has been studied on the basis of characteristic thermochemical properties using density functional theory. The influence of the solvent polarity has also been evaluated. It is found that retinol may act in parallel as an effective antioxidant via H atom donating as well as a pro-oxidant in yielding reactive hydroxyl radical. In fact, the lowest values of bond dissociation enthalpy were found at the C18-H and C18-OH positions. Retinol was also determined to be a good electron donor but bad acceptor in the single electron transfer (ET) reaction with hydroperoxyl (HOO) radical. In addition, potential energy surfaces of H atom transfer (HAT) and radical adduct formation (RAF) reactions between retinol and HOO radical were also investigated in the gas phase and in the solvent. The results demonstrated that the RAF mechanism was generally more predominant than ET and HAT ones. The most favored radical addition position was found at the C2═C3 double bond in the cyclohexenyl ring. Moreover, the radical scavenging reactivity via RAF reactions was strongly exergonic and thermodynamically feasible while the ET one was endergonic. Natural bond orbital analysis showed that the lone pairs of electrons on the oxygen atom of the HOO radical were donated to the unoccupied antibonding orbital of transferred H atom in HAT reactions. In contrast, in the case of RAF reactions, strong interactions between 2p orbitals on oxygen atoms of the radical and the π orbital of the double bond on the retinol molecule were recognized. The results obtained in this work were in agreement with previous experimental observations.

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Section: ■ Results and Discussionmentioning

confidence: 55%

“…It was well-known that vitamin A is preferably soluble in nonpolarized solvent. Indeed, Wilkie extracted vitamin A using chloroform (ε = 4.7113) and diethyl ether (ε = 4.2400) as solvents . In this experiment, the latter was found to have an appreciably higher absorption value than the former.…”

Section: Resultsmentioning

confidence: 86%

Is Vitamin A an Antioxidant or a Pro-oxidant?

et al. 2017

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Diseases of Nutrition

Butt¹

1943

Arch Intern Med (Chic)

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Vitamin A added to fats as related to stability during baking

et al. 1941

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Summary Various types of baked goods prepared from fats fortified with vitamin A have been assayed for the vitamin by the Carr‐Price color reaction and by U.S.P. bio‐assays. In products such as bread, biscuits, and cake, which are baked under moderate conditions, it appears that 80 to 100 per cent of the vitamin survives the baking process. In pie crust, which undergoes more severe baking conditions, considerable destruction, depending on the extent of the baking, is likely to occur.

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Physical and Chemical Determination of Vitamin A

Cited by 8 publications

References 34 publications

Is Vitamin A an Antioxidant or a Pro-oxidant?

Is Vitamin A an Antioxidant or a Pro-oxidant?

Diseases of Nutrition

Vitamin A added to fats as related to stability during baking

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