Rosmarinic acid, major phenolic constituent of Greek sage herbal tea, modulates rat intestinal SGLT1 levels with effects on blood glucose

Mol Nutr Food Res. 2011 May:55 Suppl 1:S15-25. doi: 10.1002/mnfr.201000472. Epub 2011 Mar 24.


Scope: 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).

Methods and 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.

Conclusion: SFT and RA modulate the trafficking of SGLT1 to the BBM and may contribute to the control of plasma glucose.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Glucose / analysis*
  • Cinnamates / pharmacology*
  • Depsides / pharmacology*
  • Diabetes Mellitus, Experimental
  • Enterocytes / metabolism
  • Glucagon-Like Peptide 1 / metabolism
  • Glucose Transporter Type 2 / metabolism
  • Hypoglycemic Agents / pharmacology
  • Intestinal Mucosa / metabolism
  • Jejunum / metabolism
  • Male
  • Microvilli / metabolism
  • Plant Preparations / pharmacology*
  • Rats
  • Rats, Wistar
  • Rosmarinic Acid
  • Salvia officinalis / chemistry*
  • Sodium-Glucose Transporter 1 / analysis*
  • Sodium-Glucose Transporter 1 / metabolism


  • Blood Glucose
  • Cinnamates
  • Depsides
  • Glucose Transporter Type 2
  • Hypoglycemic Agents
  • Plant Preparations
  • Slc5a1 protein, rat
  • Sodium-Glucose Transporter 1
  • Glucagon-Like Peptide 1