Alpha-tocopheryl acetate is absorbed and hydrolyzed by Caco-2 cells comparative studies with alpha-tocopherol.
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.
Brisson
Lydie
L
BiosCiences FRE CNRS 3005-Université Paul Cézanne-Aix Marseille III, Case 342, Faculté des Sciences et Techniques de Saint Jérôme, 13397 Marseille, France.
Castan
Stéphane
S
Fontbonne
Hervé
H
Nicoletti
Cendrine
C
Puigserver
Antoine
A
Ajandouz
El Hassan
el H
D000042:Absorption; D018938:Caco-2 Cells / Q000737:chemistry / Q000378:metabolism; D020895:Enterocytes / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism; D008823:Micelles; D018613:Microscopy, Confocal; D008954:Models, Biological; D012995:Solubility; D002787:Sterol Esterase / Q000737:chemistry / Q000378:metabolism; D013656:Taurocholic Acid / Q000737:chemistry / Q000378:metabolism; D013997:Time Factors; D024505:Tocopherols; D014810:Vitamin E / Q000737:chemistry* / Q000378:metabolism; D024502:alpha-Tocopherol / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000378:metabolism
D008823:Micelles; D014810:Vitamin E; D013656:Taurocholic Acid; D002787:Sterol Esterase; D024502:alpha-Tocopherol; D024505:Tocopherols