Studies on Absorption and Hydrolysis of Ethyl α-d-Glucoside in Rat Intestine

Abstract

Ethyl alpha-D-glucoside (alpha-EG) is normally contained in Sake, which has been taken by Japanese people since ancient times. In this study, the intestinal absorption of alpha-EG was investigated using rat everted intestinal sac. Furthermore, the alpha-EG hydrolytic activity in rat intestine was compared with disaccharides hydrolytic activities, and the effects of alpha-EG on disaccharides hydrolysis were examined using crude enzyme preparation from rat intestinal acetone powder. Glucose liberated from alpha-EG was detected in a serosal solution of everted rat intestinal sac, but it was only less than 4% of absorbed intact alpha-EG. alpha-EG absorption into small intestinal tissue was reduced by elimination of sodium ion from the mucosal solution or under the presence of phlorizin. The hydrolytic activity for alpha-EG was detected in crude enzyme preparation from rat intestinal acetone powder, but it showed a low value as compared to those for disaccharides. alpha-EG showed mixed type inhibition for maltose and sucrose hydrolysis, but inhibitory concentrations of alpha-EG required for 50% inhibition for the maltose and sucrose hydrolysis were higher than those of arabinose and acarbose. In conclusion, a small amount of alpha-EG was hydrolyzed and most of it was absorbed via SGLT1 as an intact form in the rat small intestine, and the inhibitory effect of alpha-EG on disaccharides hydrolysis was weak.

Synthesis of long-chain isomaltooligosaccharides from tapioca starch and an in vitro investigation of their prebiotic properties

“…Maltose and commercial IMOs were used as controls. The indigestible products were determined by HPAEC-PAD [23,24].…”

Plasma Kinetics and Urine Profile of Ethyl Glucosides after Oral Administration in the Rat

“…7) Furthermore, -EG was detected in the plasma of rats fed -EG solution as a daily drink. 8) As shown in Fig.…”

“…8) Some -EG was hydrolyzed in the small intestinal mucosa before absorption, and subsequently -EG absorbed into blood stream was presumably metabolized in the kidneys, but in an in vitro examination, hydrolyzing activity for -EG was much lower than that for disaccharides. 7,8) Hence ingested -EG was not hydrolyzed completely, and consequently it was excreted into the urine. On the other hand, the -EG administered was recovered from the urine as well as -EG.…”

“…5) To explain the mechanism of these physiological effects, it is important to investigate the plasma kinetics of EGs. In a previous paper, we reported that -EG was transported though the rat small intestinal wall 7) and was detected in the plasma and urine of the rats fed -EG. 8,9) Some researchers have reported that -EG and -EG were transported through the small intestinal wall, 10,11) indicating that -EG ingested orally might be absorbed into blood stream through the small intestinal wall as well as -EG.…”

Effects of ethyl-α-d-glucoside on human dermal fibroblasts

“…[8][9][10] Experiments have shown that, in mice, α-EG is absorbed by intestinal epithelial cells via sodium-dependent glucose transporter 1. 11) A study in human volunteers had demonstrated that approximately 80% of α-EG was promptly discharged through urine within 24 h after ingestion. 12) Based on these reports, we postulated that α-EG was likely transported to the stratum corneum after being absorbed by the small intestine and transferred into circulation.…”