Abstract
Glycolipids are widely distributed in nature. Although glycolipids are ingested daily in various foods, details of their intestinal absorption and nutritional function are unclear. We have developed optimal HPLC conditions for separation and quantification of glycolipids using an evaporative light-scattering detector. In animal studies, we found that completely deacylated galactosylglycerols are not absorbed or degraded in the intestine after oral administration of glyceroglycolipids. Moreover, dietary supplementation with plant glycolipids may help to improve the lower digestive tract environment. We also investigated the digestion and absorption of dietary sphingoglycolipids, and our results indicated that uptake of sphingosine is significantly higher than those of other sphingoid bases prepared from plant and yeast. P-glycoprotein (MDR1) in intestinal cells probably contributes to this selective absorption of sphingosine from dietary sphingolipids in the digestive tract. The apoptosis-inducing activity of various sphingoid bases was also confirmed. We demonstrated that formation of aberrant crypt foci induced by 1,2-dimethylhydrazine could be inhibited in the mouse large intestine by maize and yeast cerebrosides. These findings offer new insight into the nutritional function of dietary glycolipids.
