Synthesis and analysis of conjugates of the major vitamin E metabolite, α-CEHC

Pope, Simon; Burtin, Guillaume; Clayton, Peter T.; Madge, David J.; Muller, D. P. R.

doi:10.1016/s0891-5849(02)00974-7

Cited by 67 publications

(54 citation statements)

References 18 publications

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“…This was confirmed in studies by Hashiguchi et al [175] . α-5'-COOH ether glucuronides [176] in urine of both humans and mice as well as α-5'-COOH sulfate in human urine [177] are known conjugates of ICMs. More is known about the conjugates of the SCMs.…”

Section: Conjugation Of Metabolitesmentioning

confidence: 99%

“…More is known about the conjugates of the SCMs. In humans, the majority of CEHCs are excreted via urine as glucuronides [136,147,152,155] , whereas sulfates were found only in trace amounts [177] or in significant amounts [135,136,176] . In addition, other conjugates are known for α-CEHC, such as taurine, glycine or glycine glucuronide conjugates [176] .…”

Section: Conjugation Of Metabolitesmentioning

confidence: 99%

“…While glucoside conjugates of γ-CEHC [156] and α-CEHC glutamine [176] have been only found in mice, taurine, glycine or glycine glucuronides conjugates were found [139,141] ICM Ether glucuronides Human and mouse urine [176] Sulfates Human urine [177] SCM Glucosides, glutamine Mouse [156,176] Taurine, glycine or glycine glucuronides…”

Section: Conjugation Of Metabolitesmentioning

confidence: 99%

“…With respect to the simultaneous analysis, Jiang et al [139] stated that "neither electrochemical detection nor GC-MS can be used to detect sulfated carboxychromanols because of their lack of redox activity or the inertness of the conjugated phenolic group to chemical derivatization, respectively". Pope et al [177] developed the first tandem MS-MS approach for the reliable and simultaneous detection of conjugated and non-conjugated metabolites. Since then, the analytical procedures for measuring the metabolites in both conditions were adopted for LC-MS [135] and UPLC-TOF-MS [176] .…”

Section: Analyticsmentioning

confidence: 99%

“…In some studies recombinant enzymes with distinct activities are used, such as β-glucuronidase from E. coli [144,147,157] , whereas others [149,151,[154][155][156]177] used enzymes with the combined activity of β-glucosidase and sulfatase. In these cases, glucuronidase activity is usually higher than sulfatase activity.…”

Section: Analyticsmentioning

confidence: 99%

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Complexity of vitamin E metabolism

Schmölz¹,

Birringer²,

Lorkowski³

et al. 2016

WJBC

168

134

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Bioavailability of vitamin E is influenced by several factors, most are highlighted in this review. While gender, age and genetic constitution influence vitamin E bioavailability but cannot be modified, life-style and intake of vitamin E can be. Numerous factors must be taken into account however, i.e. , when vitamin E is orally administrated, the food matrix may contain competing nutrients. The complex metabolic processes comprise intestinal absorption, vascular transport, hepatic sorting by intracellular binding proteins, such as the significant α-tocopherol-transfer protein, and hepatic metabolism. The coordinated changes involved in the hepatic metabolism of vitamin E provide an effective physiological pathway to protect tissues against the excessive accumulation of, in particular, non-α-tocopherol forms. Metabolism of vitamin E begins with one cycle of CYP4F2/CYP3A4-dependent ω-hydroxylation followed by five cycles of subsequent β-oxidation, and forms the water-soluble end-product carboxyethylhydroxychroman. All known hepatic metabolites can be conjugated and are excreted, depending on the length of their sidechain, either via urine or feces. The physiological handling of vitamin E underlies kinetics which vary between the different vitamin E forms. Here, saturation of the side-chain and also substitution of the chromanol ring system are important. Most of the metabolic reactions and processes that are involved with vitamin E are also shared by other fat soluble vitamins. Influencing interactions with other nutrients such as vitamin K or pharmaceuticals are also covered by this review. All these processes modulate the formation of vitamin E metabolites and their concentrations in tissues and body fluids. Differences in metabolism might be responsible for the discrepancies that have been observed in studies performed in vivo and in vitro using vitamin E as a REVIEW

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Section: Conjugation Of Metabolitesmentioning

confidence: 99%

Section: Conjugation Of Metabolitesmentioning

confidence: 99%

Section: Conjugation Of Metabolitesmentioning

confidence: 99%

Section: Analyticsmentioning

confidence: 99%

Section: Analyticsmentioning

confidence: 99%

See 3 more Smart Citations

Complexity of vitamin E metabolism

Schmölz¹,

Birringer²,

Lorkowski³

et al. 2016

WJBC

168

134

View full text Add to dashboard Cite

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Measurement of the Vitamin E Metabolites, Carboxyethyl Hydroxychromans (CEHCs), in Biological Samples

Leonard

Traber

2006

CP Toxicology

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Metabolites of α- and γ-tocopherol, 2,5,7,8-tetramethyl-2-(2'-carboxyethyl)-6-hydroxychroman (α-CEHC) and 2,7,8-trimethyl-2-(β-carboxyethyl)-6-hydroxychroman (γ-CEHC), respectively, are produced in the liver and have been measured in biological fluids and tissue. Compared to α-tocopherol concentrations, metabolite concentrations are as much as a factor of a thousand lower, requiring extremely sensitive methodology to attain accurate measurements. This unit presents a protocol for CEHC extraction from biological samples, and describes very specific and sensitive HPLC/MS analysis.

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A Metabolomic Perspective of Small Molecule Toxicity

Patterson

Idle

2009

General, Applied and Systems Toxicology

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Recent advances in small molecule profiling, including ultraperformance liquid chromatography and time‐of‐flight mass spectrometry, have given unprecedented views of the metabolic response to toxic stimuli. Metabolomics, the process of measuring the concentration changes in metabolites of biofluids such as urine, serum, sweat or saliva or that of intact cells, tissues or single‐celled organisms, is the missing piece of the omics puzzle (genomics, transcriptomics, proteomics) necessary for providing a holistic view (DNA, RNA, protein and metabolites) of the biological response to a toxicant. Furthermore, metabolomics is an essential addition to any toxicity biomarker‐screening programme, as evidenced by its strong foothold in both pharmaceutical and academic settings. Here we discuss metabolomic science with respect to its past and future contributions to the field of toxicology and describe blueprints necessary for conducting a well‐designed and robust metabolomics experiment from sample collection to data acquisition and analysis. Metabolomics holds great promise as a tool for advancing the field of toxicology by uncovering novel biomarkers of toxic responses and by significantly improving xenobiotic metabolite identification.

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Synthesis and analysis of conjugates of the major vitamin E metabolite, α-CEHC

Cited by 67 publications

References 18 publications

Complexity of vitamin E metabolism

Complexity of vitamin E metabolism

Measurement of the Vitamin E Metabolites, Carboxyethyl Hydroxychromans (CEHCs), in Biological Samples

A Metabolomic Perspective of Small Molecule Toxicity

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