title: Quantification of the alpha- and gamma-tocopherol metabolites 2,5,7, 8-tetramethyl-2-(2'-carboxyethyl)-6-hydroxychroman and 2,7, 8-trimethyl-2-(2'-carboxyethyl)-6-hydroxychroman in human serum.
abstract: alpha- and gamma-tocopherol are the major vitamin E compounds found in human blood and tissues. The metabolites are 2,5,7, 8-tetramethyl-2-(2'-carboxyethyl)-6-hydroxychroman (alpha-CEHC) and 2,7,8-trimethyl-2-(2'-carboxyethyl)-6-hydroxychroman (gamma-CEHC, LLU-alpha), respectively. alpha-CEHC is excreted mainly as glucuronide or sulfate conjugates in the urine. Here we describe a sensitive and reliable method to analyze alpha- and gamma-CEHC in human serum. The concentration of alpha-CEHC in human serum is in the range of 5-10 pmol/ml but increases significantly up to 200 pmol/ml upon supplementation with RRR-alpha-tocopherol. About one-third of the alpha-CEHC circulating in the blood is present as a glucuronide conjugate. Baseline levels of gamma-CEHC are about 50 to 85 pmol/ml.
authors.affiliation: Institut für Physiologische Chemie I, Heinrich-Heine-Universität Düsseldorf, Germany. wilheim.stahl@uni-duesseldorf.de
authors.forename: W
authors.initials: W
authors.lastname: Stahl
authors.forename: P
authors.initials: P
authors.lastname: Graf
authors.forename: R
authors.initials: R
authors.lastname: Brigelius-Flohé
authors.forename: W
authors.initials: W
authors.lastname: Wechter
authors.forename: H
authors.initials: H
authors.lastname: Sies
mesh_terms: D000328:Adult; D002839:Chromans / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D004563:Electrochemistry; D006801:Humans; D008875:Middle Aged; D011422:Propionates / Q000097:blood*; D015203:Reproducibility of Results; D014810:Vitamin E / Q000008:administration & dosage / Q000097:blood*
chemical_list: D002839:Chromans; D011422:Propionates; D014810:Vitamin E; C107690:2,7,8-trimethyl-2-(beta-carboxyethyl)-6-hydroxychroman; C084852:2,5,7,8-tetramethyl-2-(2'-carboxyethyl)-6-hydroxychroman