Inhibition of the facilitative sugar transporters (GLUTs) by tea extracts and catechins.
FASEB J
; 34(8): 9995-10010, 2020 08.
Article
em En
| MEDLINE
| ID: mdl-32564472
ABSTRACT
Tea polyphenolics have been suggested to possess blood glucose lowering properties by inhibiting sugar transporters in the small intestine and improving insulin sensitivity. In this report, we studied the effects of teas and tea catechins on the small intestinal sugar transporters, SGLT1 and GLUTs (GLUT1, 2 and 5). Green tea extract (GT), oolong tea extract (OT), and black tea extract (BT) inhibited glucose uptake into the intestinal Caco-2 cells with GT being the most potent inhibitor (IC50 0.077 mg/mL), followed by OT (IC50 0.136 mg/mL) and BT (IC50 0.56 mg/mL). GT and OT inhibition of glucose uptake was partial non-competitive, with an inhibitor constant (Ki ) = 0.0317 and 0.0571 mg/mL, respectively, whereas BT was pure non-competitive, Ki = 0.36 mg/mL. Oocytes injected to express small intestinal GLUTs were inhibited by teas, but SGLT1 was not. Furthermore, catechins present in teas were the predominant inhibitor of glucose uptake into Caco-2 cells, and gallated catechins the most potent CG > ECG > EGCG ≥ GCG when compared to the non-gallated catechins (C, EC, GC, and EGC). In Caco-2 cells, individual tea catechins reduced the SGLT1 gene, but not protein expression levels. In contrast, GLUT2 gene and protein expression levels were reduced after 2 hours exposure to catechins but increased after 24 hours. These in vitro studies suggest teas containing catechins may be useful dietary supplements capable of blunting postprandial glycaemia in humans, including those with or at risk to Type 2 diabetes mellitus.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Chá
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Extratos Vegetais
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Catequina
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Neoplasias do Colo
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Transportador 1 de Glucose-Sódio
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Transportador de Glucose Tipo 2
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Antioxidantes
Limite:
Animals
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Female
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Humans
Idioma:
En
Revista:
FASEB J
Assunto da revista:
BIOLOGIA
/
FISIOLOGIA
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
China