Snoussi Chahira, Ducroc Robert, Hamdaoui Mohamed Hédi, Dhaouadi Karima, Abaidi Houda, Cluzeaud Francoise, Nazaret Corinne, Le Gall Maude, Bado André
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.
Inserm UMRS1149, UFR de Médecine Paris 7, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.
J Nutr Biochem. 2014 May;25(5):557-64. doi: 10.1016/j.jnutbio.2014.01.006. Epub 2014 Feb 10.
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.
含有多酚的绿茶具有抗糖尿病和抗肥胖作用，但其作用机制尚未完全明确。在本研究中，我们首先分析并比较了绿茶叶煎剂与普通绿茶提取物中的多酚化合物[表没食子儿茶素没食子酸酯（EGCG）、表没食子儿茶素（EGC）]。其次，通过Ussing chamber体外研究、使用离体空肠袢的 ex vivo研究以及通过葡萄糖耐量试验的体内研究，探讨了急性（30分钟）或慢性（6周）口服绿茶煎剂（GTD）对肠道葡萄糖吸收的影响。最后，我们在喂食正常或高脂饮食的大鼠模型中探究了GTD对体重、血液参数以及葡萄糖转运蛋白SGLT-1、GLUT2和GLUT4相对表达的影响。煮15分钟的GTD含有最高量的酚类化合物。在禁食大鼠中，急性给予GTD可抑制SGLT-1活性，增加GLUT2活性并改善葡萄糖耐量。与GTD类似，急性给予合成酚类化合物（2/3 EGCG + 1/3 EGC）可抑制SGLT-1活性。在高脂饮食喂养的大鼠中慢性给予GTD可减少体重增加、循环甘油三酯和胆固醇，并改善葡萄糖耐量。GTD处理6周的大鼠空肠黏膜中SGLT-1显著降低，GLUT2 mRNA水平升高。此外，脂肪组织中GLUT4 mRNA水平升高。这些结果表明，富含EGCG和EGC的传统饮品GTD可降低肠道SGLT-1/GLUT2比值，这是肠细胞葡萄糖吸收调节的一个标志，并增强脂肪组织中的GLUT4，为其在控制葡萄糖稳态中的可能作用提供了新的见解。
