Cacao liquor procyanidin extract improves glucose tolerance by enhancing GLUT4 translocation and glucose uptake in skeletal muscle

Abstract

Hyperglycaemia and insulin resistance are associated with the increased risk of the metabolic syndrome and other severe health problems. The insulin-sensitive GLUT4 regulates glucose homoeostasis in skeletal muscle and adipose tissue. In this study, we investigated whether cacao liquor procyanidin (CLPr) extract, which contains epicatechin, catechin and other procyanidins, improves glucose tolerance by promoting GLUT4 translocation and enhances glucose uptake in muscle cells. Our results demonstrated that CLPr increased glucose uptake in a dose-dependent manner and promoted GLUT4 translocation to the plasma membrane of L6 myotubes. Oral administration of a single dose of CLPr suppressed the hyperglycaemic response after carbohydrate ingestion, which was accompanied by enhanced GLUT4 translocation in ICR mice. These effects of CLPr were independent of α-glucosidase inhibition in the small intestine. CLPr also promoted GLUT4 translocation in skeletal muscle of C57BL/6 mice fed a CLPr-supplemented diet for 7 d. These results indicate that CLPr is a beneficial food material for improvement of glucose tolerance by promoting GLUT4 translocation to the plasma membrane of skeletal muscle.

Effects of Microbial Metabolites of (−)-Epigallocatechin Gallate on Glucose Uptake in L6 Skeletal Muscle Cell and Glucose Tolerance in ICR Mice

“…The differentiation of L6 myoblasts to myotubes (4.0 × 10 3 cells) was performed according to the previously described method. 26) The cells were maintained in MEM containing 10% FBS for two days and incubated with MEM containing 2% FBS. Differentiated L6 myotubes were serum starved in MEM containing 0.2% BSA for 18 h. Serum-starved L6 myotubes were treated with 0.1, 1, and 3 µM EGC-M5 for 15 min and subjected to Western blotting.…”

“…Glucose uptake was determined by enzymatic fluorescence assay for 2-DG uptake in myotubes. 26) This evaluation was according to the procedure used for other dietary polyphenols. [27][28][29] Serumstarved L6 myotubes in a 96-well plate were treated with 11 kinds of metabolites dissolved with dimethyl sulfoxide (DMSO) at a final concentration of 3 µM for 4 h in 0.2% (w/v) BSA/MEM.…”

Antidiabetic actions of cocoa flavanols

“…Indeed skeletal muscle plays a crucial role in maintaining glucose homeostasis as it accounts for almost 80% of insulin‐stimulated glucose uptake in the postprandial state . Cacao liquor procyanidin extract (CLPr), which is rich in catechins and B‐type proanthocyanidins oligomers, increased glucose uptake in a dose‐dependent manner in L6 myotubes (maximum effect at 5 μg/mL) by inducing GLUT‐4 translocation, whereas GLUT‐1 and ‐4 levels did not change in the plasma membrane .…”

Japanese quince (Chaenomeles japonica L.) fruit polyphenolic extract modulates carbohydrate metabolism in HepG2 cells via AMP-activated protein kinase

“…It is well known that glucose uptake requires translocation of GLUT4 transporter from intracellular space to the plasma membrane. This process can be enhanced by AMPK-signaling pathways by procyanidins (Yamashita et al, 2012). Our results indicated that JQ polyphenolic compounds can increase GLUT4 gene expression to some extent.…”