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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

Chromatograms and MS spectra of CPs and internal standards (IS). (A) Chromatogram for a CP standard solution (50 μg/mL of each CP dissolved in 10% (v/v) THF in n-hexane); (B) Chromatogram for CP standard solution after SPE (expected concentrations for individual CPs correspond to (A)). 1–6 MS spectra of CPs derived from (A): 1 linalool (IS), 2 β-cyclocitral (β-CC), 3 1,1,6-trimethyltetraline (TMT), 4 β-ionone (β-IO), 5 methylisoeugenol (IS), and 6 dihydroactinidiolide (DHA). Reprinted from [111], under the terms of Creative Commons Attribution License.
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Figure 0006: Chromatograms and MS spectra of CPs and internal standards (IS). (A) Chromatogram for a CP standard solution (50 μg/mL of each CP dissolved in 10% (v/v) THF in n-hexane); (B) Chromatogram for CP standard solution after SPE (expected concentrations for individual CPs correspond to (A)). 1–6 MS spectra of CPs derived from (A): 1 linalool (IS), 2 β-cyclocitral (β-CC), 3 1,1,6-trimethyltetraline (TMT), 4 β-ionone (β-IO), 5 methylisoeugenol (IS), and 6 dihydroactinidiolide (DHA). Reprinted from [111], under the terms of Creative Commons Attribution License.

Mentions: VF-5ms (from Varian) and STABILWAX-DA (from Restek) have been employed to separate and identify β-CC, β-homocyclocitral, α-ionone, 2,3-epoxy-α-ionone, dihydro-β-ionone, β-IO, and DHA in Catharanthus roseus [129]. β-IO and β-CC have also been determined as odorous compounds in spiked water samples and river water by GC-ion trap MS using a DB-5 capillary column [137]. Volatile CPs have been analyzed by GC-EI-Q ion trap MS using a HP-5MS column with 5% diphenylsiloxane monomer as stationary phase. Different temperature gradients were applied for the analysis of (i) neutral and (ii) acidic and alkaline fractions [133]. GC with flame ionization detection (FID) and MS detection have been applied for the analysis of volatile flavor compounds, including β-IO and derivatives, and DHA in fruits. A SolGel-Wax capillary column was employed in both cases [126]. CPs stemming from cyanobacteria were analyzed by means of a DB-624 column [127]. Our group has used a DB-20 WAX column from Agilent to separate β-CC, β-IO, DHA, and 1,1,6-trimethyltetraline (TMT), including two internal standards. A temperature gradient that raised the column temperature from 65°C to 220°C was used to separate analytes within 24 min (Figure 6) [111].


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

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

Chromatograms and MS spectra of CPs and internal standards (IS). (A) Chromatogram for a CP standard solution (50 μg/mL of each CP dissolved in 10% (v/v) THF in n-hexane); (B) Chromatogram for CP standard solution after SPE (expected concentrations for individual CPs correspond to (A)). 1–6 MS spectra of CPs derived from (A): 1 linalool (IS), 2 β-cyclocitral (β-CC), 3 1,1,6-trimethyltetraline (TMT), 4 β-ionone (β-IO), 5 methylisoeugenol (IS), and 6 dihydroactinidiolide (DHA). Reprinted from [111], under the terms of Creative Commons Attribution License.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 0006: Chromatograms and MS spectra of CPs and internal standards (IS). (A) Chromatogram for a CP standard solution (50 μg/mL of each CP dissolved in 10% (v/v) THF in n-hexane); (B) Chromatogram for CP standard solution after SPE (expected concentrations for individual CPs correspond to (A)). 1–6 MS spectra of CPs derived from (A): 1 linalool (IS), 2 β-cyclocitral (β-CC), 3 1,1,6-trimethyltetraline (TMT), 4 β-ionone (β-IO), 5 methylisoeugenol (IS), and 6 dihydroactinidiolide (DHA). Reprinted from [111], under the terms of Creative Commons Attribution License.
Mentions: VF-5ms (from Varian) and STABILWAX-DA (from Restek) have been employed to separate and identify β-CC, β-homocyclocitral, α-ionone, 2,3-epoxy-α-ionone, dihydro-β-ionone, β-IO, and DHA in Catharanthus roseus [129]. β-IO and β-CC have also been determined as odorous compounds in spiked water samples and river water by GC-ion trap MS using a DB-5 capillary column [137]. Volatile CPs have been analyzed by GC-EI-Q ion trap MS using a HP-5MS column with 5% diphenylsiloxane monomer as stationary phase. Different temperature gradients were applied for the analysis of (i) neutral and (ii) acidic and alkaline fractions [133]. GC with flame ionization detection (FID) and MS detection have been applied for the analysis of volatile flavor compounds, including β-IO and derivatives, and DHA in fruits. A SolGel-Wax capillary column was employed in both cases [126]. CPs stemming from cyanobacteria were analyzed by means of a DB-624 column [127]. Our group has used a DB-20 WAX column from Agilent to separate β-CC, β-IO, DHA, and 1,1,6-trimethyltetraline (TMT), including two internal standards. A temperature gradient that raised the column temperature from 65°C to 220°C was used to separate analytes within 24 min (Figure 6) [111].

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