Attenuation of glucose transport across Caco-2 cell monolayers by a polyphenol-rich herbal extract: interactions with SGLT1 and GLUT2 transporters.
Previous studies have indicated that secondary plant metabolites may modulate glucose absorption in the small intestine. We have characterized a polyphenol-rich herbal extract and its potential intestinal metabolites by LC-MS(2) and investigated the inhibition of glucose transporters SGLT1 and GLUT2 using the well-characterized Caco-2 intestinal model. Differentiated Caco-2 monolayers were incubated with an extract of a mixture of herbs and spices. Glucose transport under sodium-dependent and sodium-free conditions was determined by radiochemical detection of D-[U-(14) C]-glucose. A 54% decrease in transport was observed compared to control. Using sodium-dependent and sodium-free conditions, we demonstrate that the inhibition of GLUT2 was greater than SGLT1. Glycosidase and esterase enzymatic hydrolysis was used to assess the impact of metabolism on the efficacy of inhibition. Glucose transport across the membrane was reduced by 70% compared to the control and was associated with significant increases in flavonoid aglycones, caffeic acid, and p-coumaric acid. These results suggest that intact and hydrolyzed polyphenols, likely to be found in the lumen after ingestion of the supplement, play an important role in the attenuation of glucose absorption and may have potentially beneficial antiglycemic effects in the body.
School of Food Science and Nutrition, University of Leeds, Leeds, West Yorkshire, UK.
Tracy L
TL
Farrell
Samantha L
SL
Ellam
Taryn
T
Forrelli
Gary
G
Williamson
D001692:Biological Transport / Q000187:drug effects; D018938:Caco-2 Cells; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy; D004950:Esterases / Q000737:chemistry; D005947:Glucose / Q000378:metabolism; D051273:Glucose Transporter Type 2 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000737:chemistry; D006801:Humans; D006868:Hydrolysis; D007004:Hypoglycemic Agents / Q000737:chemistry / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D059808:Polyphenols / Q000737:chemistry / Q000494:pharmacology*; D051269:Sodium-Glucose Transporter 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism
D051273:Glucose Transporter Type 2; D007004:Hypoglycemic Agents; D010936:Plant Extracts; D059808:Polyphenols; C495680:SLC2A2 protein, human; C495674:SLC5A1 protein, human; D051269:Sodium-Glucose Transporter 1; D004950:Esterases; D006026:Glycoside Hydrolases; D005947:Glucose
Caco-2 cells; diabetes; glucose transporters; herbal; polyphenol