title: Inhibition of the intestinal sodium-coupled glucose transporter 1 (SGLT1) by extracts and polyphenols from apple reduces postprandial blood glucose levels in mice and humans.
abstract: METHODS
  There is a growing interest in food constituents that could reduce intestinal glucose absorption to prevent overshooting plasma glucose and insulin levels in patients with prediabetes and diabetes mellitus type 2.
  
  
  RESULTS
  We here demonstrate that an extract and individual polyphenols from apple diminish sodium-coupled glucose transporter 1 (SGLT1) mediated glucose uptake in vitro and in vivo. Inhibition of transport of sugars by SGLT1 was shown in Xenopus oocytes and in mice jejunal segments. Strongest inhibition was observed for phlorizin with IC50 values for transport inhibition of 0.46 ± 0.19 and 4.1 ± 0.6 μM in oocytes and intestinal segments, respectively. An oral glucose tolerance test performed in volunteers with prior administration of the apple extract reduced venous blood glucose and plasma insulin levels, similar to findings obtained in C57BL/6N mice. Analysis of human urine samples revealed that the extract increased modestly renal glucose loss that is most likely a result of inhibition of renal glucose reabsorption by phloretin derivatives found in plasma of the volunteers.
  
  
  CONCLUSIONS
  Although the apple extract substantially decreased intestinal glucose absorption in all test systems, the finding that there are systemic effects that relate to inhibition of glucose transport processes beyond the intestine addresses safety issues that need further exploitation.
authors: Molecular Nutrition Unit, ZIEL Research Center of Nutrition and Food Sciences, Technical University of Munich, Freising-Weihenstephan, Germany.
authors: Christine
authors: C
authors: Schulze
authors: Adina
authors: A
authors: Bangert
authors: Gabor
authors: G
authors: Kottra
authors: Kerstin Elisabeth
authors: KE
authors: Geillinger
authors: Bettina
authors: B
authors: Schwanck
authors: Henning
authors: H
authors: Vollert
authors: Wolfgang
authors: W
authors: Blaschek
authors: Hannelore
authors: H
authors: Daniel
mesh_terms: D000328:Adult; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D005260:Female; D006029:Glycosuria / Q000188:drug therapy; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D008297:Male; D027845:Malus; D008810:Mice, Inbred C57BL; D009865:Oocytes / Q000187:drug effects; D010695:Phlorhizin / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D059808:Polyphenols / Q000032:analysis / Q000494:pharmacology*; D019518:Postprandial Period / Q000187:drug effects; D051269:Sodium-Glucose Transporter 1 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D014982:Xenopus laevis; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D010936:Plant Extracts; D059808:Polyphenols; C495674:SLC5A1 protein, human; C495675:Slc5a1 protein, mouse; D051269:Sodium-Glucose Transporter 1; D010695:Phlorhizin
keywords: Antihyperglycemic; Apple; Postprandial blood glucose; SGLT1; Type 2 diabetes mellitus