Alpha-tocopheryl acetate is absorbed and hydrolyzed by Caco-2 cells comparative studies with alpha-tocopherol

Chem Phys Lipids. 2008 Jul;154(1):33-7. doi: 10.1016/j.chemphyslip.2008.04.002. Epub 2008 Apr 26.

Abstract

Caco-2 cells were used as a model for investigating and comparing the absorption of alpha-tocopherol (Tol) and alpha-tocopheryl acetate (Tac) solubilized in micelles based on a mixture of sodium taurocholate (NaTC) and oleic acid. Surprisingly, the uptake of Tac was found to be similar to that of Tol, and in both cases, the dose-response plots suggest that protein-mediated transport processes were involved. Moreover Tol or Tac were also secreted into the basolateral medium of Caco-2 cells but Tac was mainly hydrolyzed either prior to absorption or intracellularly. The solubilization of Tol or Tac by NaTC on the apical side of the cell monolayer is a prerequisite for the uptake process, although larger amounts of the bile salt are necessary to solubilize Tac than Tol. Caco-2 cells showed hydrolytic activity on Tac, and additional cholesterol esterase may be taken up by the cells, thus increasing the rates of intracellular hydrolysis of Tac. Based on our findings, a scheme is suggested accounting for the absorption of alpha-tocopheryl acetate by enterocytes.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorption
  • Caco-2 Cells* / chemistry
  • Caco-2 Cells* / metabolism
  • Enterocytes / chemistry
  • Enterocytes / metabolism
  • Humans
  • Hydrolysis
  • Intracellular Membranes / chemistry
  • Intracellular Membranes / metabolism
  • Micelles*
  • Microscopy, Confocal
  • Models, Biological
  • Solubility
  • Sterol Esterase / chemistry
  • Sterol Esterase / metabolism
  • Taurocholic Acid / chemistry
  • Taurocholic Acid / metabolism
  • Time Factors
  • Tocopherols
  • Vitamin E / chemistry*
  • Vitamin E / metabolism
  • alpha-Tocopherol / analogs & derivatives*
  • alpha-Tocopherol / chemistry*
  • alpha-Tocopherol / metabolism

Substances

  • Micelles
  • Vitamin E
  • Taurocholic Acid
  • Sterol Esterase
  • alpha-Tocopherol
  • Tocopherols