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

alpha- and gamma-tocopherol are the major vitamin E compounds found in huma n blood and tissues. The metabolites are 2,5,7,8-tetramethyl-2-(2'-carboxye thyl)6-hydroxychroman (alpha-CEHC) and 2,7,8-trimethyl-2-(2'carboxyethyl)-6 -hydroxychroman (gamma-CEHC, LLU-alpha), respectively, alpha-CEHC is excret ed mainly as glucuronide or sulfate conjugates in the urine. Here we descri be a sensitive and reliable method to analyze alpha-and gamma-CEHC in human serum. The concentration of gamma-CEHC in human serum is in the range of 5 -10 pmol/ml but increases significantly up to 200 pmol/ml upon supplementat ion with RRR-alpha-tocopherol, About one-third of the alpha-CEHC circulatin g in the blood is present as a glucuronide conjugate. Baseline levels of ga mma-CEHC are about 50 to 85 pmol/ml. (C) 1999 Academic Press.