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Analytical tools for the analysis of β-carotene and its degradation products.

Stutz H, Bresgen N, Eckl PM - Free Radic. Res. (2015)

Bottom Line: Depending on the dominant degradation mechanism, bond cleavage might occur either randomly or at defined positions of the conjugated electron system, resulting in a diversity of cleavage products (CPs).For identity confirmation of analytes, mass spectrometry (MS) is indispensable, and the appropriate ionization principles are comprehensively discussed.The final sections cover analysis of real samples and aspects of quality assurance, namely matrix effects and method validation.

View Article: PubMed Central - PubMed

Affiliation: Division of Chemistry and Bioanalytics, Department of Molecular Biology, University of Salzburg , Salzburg , Austria.

ABSTRACT
β-Carotene, the precursor of vitamin A, possesses pronounced radical scavenging properties. This has centered the attention on β-carotene dietary supplementation in healthcare as well as in the therapy of degenerative disorders and several cancer types. However, two intervention trials with β-carotene have revealed adverse effects on two proband groups, that is, cigarette smokers and asbestos-exposed workers. Beside other causative reasons, the detrimental effects observed have been related to the oxidation products of β-carotene. Their generation originates in the polyene structure of β-carotene that is beneficial for radical scavenging, but is also prone to oxidation. Depending on the dominant degradation mechanism, bond cleavage might occur either randomly or at defined positions of the conjugated electron system, resulting in a diversity of cleavage products (CPs). Due to their instability and hydrophobicity, the handling of standards and real samples containing β-carotene and related CPs requires preventive measures during specimen preparation, analyte extraction, and final analysis, to avoid artificial degradation and to preserve the initial analyte portfolio. This review critically discusses different preparation strategies of standards and treatment solutions, and also addresses their protection from oxidation. Additionally, in vitro oxidation strategies for the generation of oxidative model compounds are surveyed. Extraction methods are discussed for volatile and non-volatile CPs individually. Gas chromatography (GC), (ultra)high performance liquid chromatography (U)HPLC, and capillary electrochromatography (CEC) are reviewed as analytical tools for final analyte analysis. For identity confirmation of analytes, mass spectrometry (MS) is indispensable, and the appropriate ionization principles are comprehensively discussed. The final sections cover analysis of real samples and aspects of quality assurance, namely matrix effects and method validation.

No MeSH data available.


Related in: MedlinePlus

Degradation pathways of all-trans-β-carotene (by HOCl according to [29]) resulting in non-volatile (β-apo-carotenales) and volatile cleavage products (CPs). Analysis methods and preceding extraction methods applied for the identification and quantification of the respective CPs are stated. Details are given in the text.
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Figure 0002: Degradation pathways of all-trans-β-carotene (by HOCl according to [29]) resulting in non-volatile (β-apo-carotenales) and volatile cleavage products (CPs). Analysis methods and preceding extraction methods applied for the identification and quantification of the respective CPs are stated. Details are given in the text.

Mentions: Based on the decomposition strategy of Handelman et al. [39], Sommerburg et al. [29] degraded β-carotene in 1/10 and 1/100 (mol/mol) mixtures of HOCl/ClO−, either in methanolic solutions or an emulsion containing 70% glycerol in 30% water. The final emulsion was prepared by spiking the glycerol-water mixture with an appropriate amount of β-carotene dissolved in soybean oil. The reaction solution, prepared in a 1/100 ratio (β-carotene/NaOCl), provided β-IO, 5,6-epoxy-β-ionone, β-CC, DHA, and 4-oxo-β-ionone (Figure 2), whereas long-chain CPs were absent. In aqueous emulsions that also contained soybean oil, degradation was different and β-carotene was not completely degraded, even at the applied 1/100 ratio (Figure 2). Higher soybean contents decelerated the degradation progress. Increasing the NaOCl content increased the concentration of β-apo-12´-carotenal and retinal, whereas β-apo-8´-carotenal ceased. β-apo-4´-carotenal was not formed [29].


Analytical tools for the analysis of β-carotene and its degradation products.

Stutz H, Bresgen N, Eckl PM - Free Radic. Res. (2015)

Degradation pathways of all-trans-β-carotene (by HOCl according to [29]) resulting in non-volatile (β-apo-carotenales) and volatile cleavage products (CPs). Analysis methods and preceding extraction methods applied for the identification and quantification of the respective CPs are stated. Details are given in the text.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4487603&req=5

Figure 0002: Degradation pathways of all-trans-β-carotene (by HOCl according to [29]) resulting in non-volatile (β-apo-carotenales) and volatile cleavage products (CPs). Analysis methods and preceding extraction methods applied for the identification and quantification of the respective CPs are stated. Details are given in the text.
Mentions: Based on the decomposition strategy of Handelman et al. [39], Sommerburg et al. [29] degraded β-carotene in 1/10 and 1/100 (mol/mol) mixtures of HOCl/ClO−, either in methanolic solutions or an emulsion containing 70% glycerol in 30% water. The final emulsion was prepared by spiking the glycerol-water mixture with an appropriate amount of β-carotene dissolved in soybean oil. The reaction solution, prepared in a 1/100 ratio (β-carotene/NaOCl), provided β-IO, 5,6-epoxy-β-ionone, β-CC, DHA, and 4-oxo-β-ionone (Figure 2), whereas long-chain CPs were absent. In aqueous emulsions that also contained soybean oil, degradation was different and β-carotene was not completely degraded, even at the applied 1/100 ratio (Figure 2). Higher soybean contents decelerated the degradation progress. Increasing the NaOCl content increased the concentration of β-apo-12´-carotenal and retinal, whereas β-apo-8´-carotenal ceased. β-apo-4´-carotenal was not formed [29].

Bottom Line: Depending on the dominant degradation mechanism, bond cleavage might occur either randomly or at defined positions of the conjugated electron system, resulting in a diversity of cleavage products (CPs).For identity confirmation of analytes, mass spectrometry (MS) is indispensable, and the appropriate ionization principles are comprehensively discussed.The final sections cover analysis of real samples and aspects of quality assurance, namely matrix effects and method validation.

View Article: PubMed Central - PubMed

Affiliation: Division of Chemistry and Bioanalytics, Department of Molecular Biology, University of Salzburg , Salzburg , Austria.

ABSTRACT
β-Carotene, the precursor of vitamin A, possesses pronounced radical scavenging properties. This has centered the attention on β-carotene dietary supplementation in healthcare as well as in the therapy of degenerative disorders and several cancer types. However, two intervention trials with β-carotene have revealed adverse effects on two proband groups, that is, cigarette smokers and asbestos-exposed workers. Beside other causative reasons, the detrimental effects observed have been related to the oxidation products of β-carotene. Their generation originates in the polyene structure of β-carotene that is beneficial for radical scavenging, but is also prone to oxidation. Depending on the dominant degradation mechanism, bond cleavage might occur either randomly or at defined positions of the conjugated electron system, resulting in a diversity of cleavage products (CPs). Due to their instability and hydrophobicity, the handling of standards and real samples containing β-carotene and related CPs requires preventive measures during specimen preparation, analyte extraction, and final analysis, to avoid artificial degradation and to preserve the initial analyte portfolio. This review critically discusses different preparation strategies of standards and treatment solutions, and also addresses their protection from oxidation. Additionally, in vitro oxidation strategies for the generation of oxidative model compounds are surveyed. Extraction methods are discussed for volatile and non-volatile CPs individually. Gas chromatography (GC), (ultra)high performance liquid chromatography (U)HPLC, and capillary electrochromatography (CEC) are reviewed as analytical tools for final analyte analysis. For identity confirmation of analytes, mass spectrometry (MS) is indispensable, and the appropriate ionization principles are comprehensively discussed. The final sections cover analysis of real samples and aspects of quality assurance, namely matrix effects and method validation.

No MeSH data available.


Related in: MedlinePlus