Glyceroglycolipids Affect Uptake of Carotenoids Solubilized in Mixed Micelles by Human Intestinal Caco‐2 Cells

Abstract

We previously reported that phospholipids markedly affected the uptake of carotenoids solubilized in mixed micelles by human intestinal Caco‐2 cells. In the present study, we found that two classes of dietary glyceroglycolipids and the corresponding lysoglyceroglycolipids affected uptake of β‐carotene and lutein by differentiated Caco‐2 cells. The levels of carotenoid uptake from micelles containing digalactosyldiacylglycerol or sulfoquinovosyldiacylglycerol were significantly lower than that from control micelles. On the other hand, the uptakes from micelles containing digalactosylmonoacylglycerol or sulfoquinovosylmonoacylglycerol were significantly higher than that from control micelles. In dispersed cells and Caco‐2 cells with poor cell‐to‐cell adhesion, however, the levels of uptake from micelles containing these lyso‐lipids were much lower than that from control micelles. The uptake levels from control micelles were markedly decreased depending on the development of cell‐to‐cell/cell–matrix adhesion in Caco‐2 cells, but the uptake levels from the micelles containing these lyso‐lipids were not substantially changed, suggesting that the intercellular barrier formed by cell‐to‐cell/cell–matrix adhesion inhibited the uptake from control micelles, but not from the lyso‐lipid‐containing micelles. The lyso‐lipids appeared to enhance carotenoid uptake by decreasing the intercellular barrier integrity. The results showed that some types of glyceroglycolipids have the potential to modify the intestinal uptake of carotenoids.

Lysoglyceroglycolipids Improve the Intestinal Absorption of Micellar Fucoxanthin by Caco-2 Cells

“…This result, together with our previous report 7 on the uptake of β-carotene and lutein, suggests that these lysoGLs enhance the absorption of various carotenoids with different polarities. We previously reported that the integrity of the intercellular barrier formed by cellto-cell/cell-matrix adhesion participated in the mechanism underlying the effect of lyso-lipids on the carotenoid uptake by Caco-2 cells 7 . In brief, DGMG and SQMG would enhance carotenoid uptake by decreasing the intercellular barrier integrity through the removal of cellular cholesterol, and this applies to carotenoids of a wide polarity range.…”

“…However, in the present study, there was no association between the amount of residual micellar carotenoid and the uptake. In addition, we previously found that the concentration of micellar carotenoid at the end of the incubation was not an important factor modulating the uptake 7 .…”

“…The apical medium was collected to evaluate residual micellar fucoxanthin and fucoxanthinol, and then diluted 9-fold with DMSO/methanol 2:7, v/v . These samples were analyzed by HPLC as described previously 7 . The solvent system consisted of acetonitrile/methanol/water 75:15:10, v/v/v , containing 0.1 ammonium acetate.…”

“…The solvent system consisted of acetonitrile/methanol/water 75:15:10, v/v/v , containing 0.1 ammonium acetate. Cellular protein contents were determined as described previously 7 .…”

“…An increase in intestinal absorption is thus a critical factor in increasing the carotenoid bioavailability. We recently found that lyso-lipids derived from dietary glyceroglycolipids GLs such as digalactosyldiacylglycerol DGDG and sulfoquinovosyldiacylglycerol SQDG enhanced the uptake of carotenoids such as β-carotene and lutein solubilized in mixed micelles by human intestinal Caco-2 cells 7 . In the present study, we evaluated the effect of glyceroglycolipids not only on the uptake but also on the transport of fucoxanthin through Caco-2 monolayers in the Transwell plates.…”