In situ absorption and metabolism of stilbene glycoside in rat

Stilbene glycoside (TSG) has been shown to have many beneficial properties. It is therefore essential to understand the absorption and metabolism of TSG in detail. We determined the recovery of TSG and its metabolites (TSG sulfate/glucuronides) in rat gastric contents, gastric mucosa, portal vein plasma, celiac arterial plasma, bile, and urine after administration of 15mg of TSG in 0.5mL physiological saline or incubation for 20min in situ in the stomach of rats. Within 20min, (64.0±9.8)% of the administered TSG disappeared from the stomach; later, TSG was recovered in both free and conjugated forms in plasma and bile, but not in urine. On the other hand, only free TSG was detected in the gastric contents and mucosa; it was also detected in the portal vein plasma as (48.1±3.5)% of the total TSG (all forms of TSG). However, the proportion of free TSG in the celiac arterial plasma and bile decreased to 4%-10%. In addition, the proportion of free TSG to total TSG in the liver microsome incubation mixture after TSG was incubated in liver microsome at 37℃ for 30min was very low (10.6 ± 2.6)%]. These results indicate that TSG could be quickly absorbed from the rat stomach, conjugated in liver and excreted in bile. Such novel information would be helpful for the use of TSG as a beneficial natural product which may improve its proposed efficacy in preventing chronic diseases.