title: Rosmarinic acid, major phenolic constituent of Greek sage herbal tea, modulates rat intestinal SGLT1 levels with effects on blood glucose.
abstract: METHODS
  Previous results suggested that the effects of Salvia fruticosa tea (SFT) drinking on glucose regulation might be at the intestinal level. Here we aim to characterize the effects of SFT treatment and of its main phenolic constituent--rosmarinic acid (RA)--on the levels and localization of the intestinal Na+/glucose cotransporter-1 (SGLT1), the facilitative glucose transporter 2 and glucagon-like peptide-1 (GLP-1).
  
  
  RESULTS
  Two models of SGLT1 induction in rats were used: through diabetes induction with streptozotocin (STZ) and through dietary carbohydrate manipulation. Drinking water was replaced with SFT or RA and blood parameters, liver glycogen and the levels of different proteins in enterocytes quantified. Two weeks of SFT treatment stabilized fasting blood glucose levels in STZ-diabetic animals. The increase in SGLT1 localized to the enterocyte brush-border membrane (BBM) induced by STZ treatment was significantly abrogated by treatment with SFT, without significant changes in total cellular transporter protein levels. No effects were observed on glucose transporter 2, Na(+) /K(+) -ATPase or glucagon-like peptide-1 levels by SFT. Additionally, SFT and RA for 4 days significantly inhibited the carbohydrate-induced adaptive increase of SGLT1 in BBM.
  
  
  CONCLUSIONS
  SFT and RA modulate the trafficking of SGLT1 to the BBM and may contribute to the control of plasma glucose.
authors: Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Braga, Portugal.
authors: Marisa F
authors: MF
authors: Azevedo
authors: Cristovao F
authors: CF
authors: Lima
authors: Manuel
authors: M
authors: Fernandes-Ferreira
authors: Maria Judite
authors: MJ
authors: Almeida
authors: Jonathan M
authors: JM
authors: Wilson
authors: Cristina
authors: C
authors: Pereira-Wilson
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D002934:Cinnamates / Q000494:pharmacology*; D053630:Depsides / Q000494:pharmacology*; D003921:Diabetes Mellitus, Experimental; D020895:Enterocytes / Q000378:metabolism; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism; D051273:Glucose Transporter Type 2 / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000378:metabolism; D007583:Jejunum / Q000378:metabolism; D008297:Male; D008871:Microvilli / Q000378:metabolism; D028321:Plant Preparations / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D027543:Salvia officinalis / Q000737:chemistry*; D051269:Sodium-Glucose Transporter 1 / Q000032:analysis* / Q000378:metabolism; D000097123:Rosmarinic Acid
chemical_list: D001786:Blood Glucose; D002934:Cinnamates; D053630:Depsides; D052216:Glucagon-Like Peptide 1; D051273:Glucose Transporter Type 2; D007004:Hypoglycemic Agents; D028321:Plant Preparations; D051269:Sodium-Glucose Transporter 1; D000097123:Rosmarinic Acid; C495676:Slc5a1 protein, rat