Original Article

Naunyn-Schmiedeberg's Archives of Pharmacology

, Volume 386, Issue 8, pp 733-745

Green tea extract with polyethylene glycol-3350 reduces body weight and improves glucose tolerance in db/db and high-fat diet mice

  • Jae-Hyung ParkAffiliated withDepartment of Physiology and Endocrinology, Keimyung University School of Medicine
  • , Yoon Jung ChoiAffiliated withDepartment of Physiology, Yeongnam University School of Medicine
  • , Yong Woon KimAffiliated withDepartment of Physiology, Yeongnam University School of Medicine
  • , Sang Pyo KimAffiliated withDepartment of Pathology, Keimyung University School of Medicine
  • , Ho-Chan ChoAffiliated withDepartment of Physiology and Endocrinology, Keimyung University School of Medicine
  • , Shinbyoung AhnAffiliated withGCB R&D and Clinical Trial Center Co., Ltd.
  • , Ki-Cheor BaeAffiliated withDepartment of Physiology and Endocrinology, Keimyung University School of Medicine
  • , Seung-Soon ImAffiliated withDepartment of Physiology and Endocrinology, Keimyung University School of Medicine
  • , Jae-Hoon BaeAffiliated withDepartment of Physiology and Endocrinology, Keimyung University School of Medicine
    • , Dae-Kyu SongAffiliated withDepartment of Physiology and Endocrinology, Keimyung University School of Medicine Email author 

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Abstract

Green tea extract (GTE) is regarded to be effective against obesity and type 2 diabetes, but definitive evidences have not been proven. Based on the assumption that the gallated catechins (GCs) in GTE attenuate intestinal glucose and lipid absorption, while enhancing insulin resistance when GCs are present in the circulation through inhibiting cellular glucose uptake in various tissues, this study attempted to block the intestinal absorption of GCs and prolong their residence time in the lumen. We then observed whether GTE containing the nonabsorbable GCs could ameliorate body weight (BW) gain and glucose intolerance in db/db and high-fat diet mice. Inhibition of the intestinal absorption of GCs was accomplished by co-administering the nontoxic polymer polyethylene glycol-3350 (PEG). C57BLKS/J db/db and high-fat diet C57BL/6 mice were treated for 4 weeks with drugs as follows: GTE, PEG, GTE + PEG, voglibose, or pioglitazone. GTE mixed with meals did not have any ameliorating effects on BW gain and glucose intolerance. However, the administration of GTE plus PEG significantly reduced BW gain, insulin resistance, and glucose intolerance, without affecting food intake and appetite. The effect was comparable to the effects of an α-glucosidase inhibitor and a peroxisome proliferator-activated receptor-γ/α agonist. These results indicate that prolonging the action of GCs of GTE in the intestinal lumen and blocking their entry into the circulation may allow GTE to be used as a prevention and treatment for both obesity and obesity-induced type 2 diabetes.

Keywords

Obesity Diabetes Green tea extract Polyethylene glycol Glucose uptake Lipid absorption