Analysis of vitamin E metabolites including carboxychromanols and sulfated derivatives using LC/MS/MS.
Tocopherols and tocotrienols are metabolized via hydroxylation and oxidation of their hydrophobic side chain to generate 13'-hydroxychromanols (13'-OHs) and various carboxychromanols, which can be further metabolized by conjugation including sulfation. Recent studies indicate that long-chain carboxychromanols, especially 13'-carboxychromanol (13'-COOH), appear to be more bioactive than tocopherols in anti-inflammatory and anticancer actions. To understand the potential contribution of metabolites to vitamin E-mediated effects, an accurate assay is needed to evaluate bioavailability of these metabolites. Here we describe an LC/MS/MS assay for quantifying vitamin E metabolites using negative polarity ESI. This assay includes a reliable sample extraction procedure with efficacy of ≥ 89% and interday/intraday variation of 3-11% for major metabolites. To ensure accurate quantification, short-chain, long-chain, and sulfated carboxychromanols are included as external/internal standards. Using this assay, we observed that sulfated carboxychromanols are the primary metabolites in the plasma of rodents fed with γ-tocopherol or δ-tocopherol. Although plasma levels of 13'-COOHs and 13'-OHs are low, high concentrations of these compounds are found in feces. Our study demonstrates an LC/MS/MS assay for quantitation of sulfated and unconjugated vitamin E metabolites, and this assay will be useful for evaluating the role of these metabolites in vivo.
Department of Nutrition Science, Purdue University, West Lafayette, IN 47907.
Qing
Q
Jiang
Department of Nutrition Science, Purdue University, West Lafayette, IN 47907.
Tianlin
T
Xu
Department of Nutrition Science, Purdue University, West Lafayette, IN 47907.
Jianjie
J
Huang
Metabolite Profiling Facility Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907.
Amber S
AS
Jannasch
Metabolite Profiling Facility Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907.
Bruce
B
Cooper
Department of Nutrition Science, Purdue University, West Lafayette, IN 47907.
Chao
C
Yang
D000818:Animals; D001774:Blood Chemical Analysis; D045744:Cell Line, Tumor; D002839:Chromans / Q000097:blood* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D005243:Feces / Q000737:chemistry; D006801:Humans; D008297:Male; D008807:Mice, Inbred BALB C; D010084:Oxidation-Reduction; D017208:Rats, Wistar; D053719:Tandem Mass Spectrometry; D016482:Urinalysis; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000097:blood* / Q000737:chemistry
D002839:Chromans; D014810:Vitamin E
liquid chromatography tandem mass spectrometry; metabolism; sulfation; tocopherol; tocotrienol