title: Green tea decoction improves glucose tolerance and reduces weight gain of rats fed normal and high-fat diet.
abstract: Green tea containing polyphenols exerts antidiabetic and antiobesity effects, but the mechanisms involved are not fully understood. In this study, we first analyzed and compared polyphenol compounds [epigallocatechin gallate (EGCG), epigallocatechin (EGC)] in decoction of green tea leaves versus usual green tea extracts. Second, the effects of acute (30 min) or chronic (6 weeks) oral administration of green tea decoction (GTD) on intestinal glucose absorption were studied in vitro in Ussing chamber, ex vivo using isolated jejunal loops and in vivo through glucose tolerance tests. Finally, we explore in rat model fed normal or high-fat diet the effects of GTD on body weight, blood parameters and on the relative expression of glucose transporters SGLT-1, GLUT2 and GLUT4. GTD cooked for 15 min contained the highest amounts of phenolic compounds. In fasted rats, acute administration of GTD inhibited SGLT-1 activity, increased GLUT2 activity and improved glucose tolerance. Similarly to GTD, acute administration of synthetic phenolic compounds (2/3 EGCG+1/3 EGC) inhibited SGLT-1 activity. Chronic administration of GTD in rat fed high-fat diet reduced body weight gain, circulating triglycerides and cholesterol and improved glucose tolerance. GTD-treated rats for 6 weeks display significantly reduced SGLT-1 and increased GLUT2 mRNA levels in the jejunum mucosa. Moreover, adipose tissue GLUT4 mRNA levels were increased. These results indicate that GTD, a traditional beverage rich in EGCG and EGC reduces intestinal SGLT-1/GLUT2 ratio, a hallmark of regulation of glucose absorption in enterocyte, and enhances adipose GLUT4 providing new insights in its possible role in the control of glucose homeostasis.
authors.affiliation: Inserm UMRS1149, UFR de Médecine Paris 7, Université Paris Diderot, Sorbonne Paris Cité, Paris, France; Research Unit on the Antioxidant compounds, Oxidative stress, Trace elements and Metabolic diseases, ESSTST, Tunis, Tunisia.
authors.forename: Chahira
authors.initials: C
authors.lastname: Snoussi
authors.affiliation: Inserm UMRS1149, UFR de Médecine Paris 7, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.
authors.forename: Robert
authors.initials: R
authors.lastname: Ducroc
authors.affiliation: Research Unit on the Antioxidant compounds, Oxidative stress, Trace elements and Metabolic diseases, ESSTST, Tunis, Tunisia.
authors.forename: Mohamed Hédi
authors.initials: MH
authors.lastname: Hamdaoui
authors.affiliation: Food Biochemistry Laboratory, INSAT, Tunis, Tunisia.
authors.forename: Karima
authors.initials: K
authors.lastname: Dhaouadi
authors.affiliation: Research Unit on the Antioxidant compounds, Oxidative stress, Trace elements and Metabolic diseases, ESSTST, Tunis, Tunisia.
authors.forename: Houda
authors.initials: H
authors.lastname: Abaidi
authors.affiliation: Inserm UMRS1149, UFR de Médecine Paris 7, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.
authors.forename: Francoise
authors.initials: F
authors.lastname: Cluzeaud
authors.affiliation: Inserm UMRS1149, UFR de Médecine Paris 7, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Nazaret
authors.affiliation: Inserm UMRS1149, UFR de Médecine Paris 7, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.
authors.forename: Maude
authors.initials: M
authors.lastname: Le Gall
authors.affiliation: Inserm UMRS1149, UFR de Médecine Paris 7, Université Paris Diderot, Sorbonne Paris Cité, Paris, France. Electronic address: andre.bado@inserm.fr.
authors.forename: André
authors.initials: A
authors.lastname: Bado
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002110:Caffeine / Q000032:analysis / Q000494:pharmacology; D002392:Catechin / Q000031:analogs & derivatives / Q000032:analysis / Q000494:pharmacology; D059305:Diet, High-Fat / Q000009:adverse effects*; D005947:Glucose / Q000378:metabolism; D005951:Glucose Tolerance Test; D051273:Glucose Transporter Type 2 / Q000235:genetics / Q000378:metabolism; D051275:Glucose Transporter Type 4 / Q000235:genetics; D008055:Lipids / Q000097:blood; D008297:Male; D059808:Polyphenols / Q000032:analysis / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects; D017208:Rats, Wistar; D051269:Sodium-Glucose Transporter 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D013662:Tea / Q000737:chemistry; D015430:Weight Gain / Q000187:drug effects*
chemical_list: D051273:Glucose Transporter Type 2; D051275:Glucose Transporter Type 4; D008055:Lipids; D059808:Polyphenols; C495683:Slc2a2 protein, rat; C495694:Slc2a4 protein, rat; C495676:Slc5a1 protein, rat; D051269:Sodium-Glucose Transporter 1; D013662:Tea; D002110:Caffeine; D002392:Catechin; C045651:epigallocatechin gallate; C057580:gallocatechol; D005947:Glucose
keywords: EGC; EGCG; GLUT2; GLUT4; Green tea decoction; Intestine; SGLT-1