3-O-Acyl-epicatechins Increase Glucose Uptake Activity and GLUT4 Translocation through Activation of PI3K Signaling in Skeletal Muscle Cells

• Published in: International journal of molecular sciences Vol. 16; no. 7; pp. 16288 - 16299
• Main Authors: Ueda-Wakagi, Manabu, Mukai, Rie, Fuse, Naoya, Mizushina, Yoshiyuki, Ashida, Hitoshi
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 17.07.2015; MDPI
• Subjects: Animals; Catechin - chemistry; Catechin - pharmacology; Cellular biology; Glucose; Glucose - metabolism; Glucose Transporter Type 4 - metabolism; Insulin; Insulin - pharmacology; Lipid Bilayers - metabolism; Muscle Cells - drug effects; Muscle Cells - metabolism; Muscle Fibers, Skeletal - drug effects; Muscle Fibers, Skeletal - metabolism; Muscle, Skeletal - cytology; Phosphatidylinositol 3-Kinases - metabolism; Polyphenols; Protein Transport - drug effects; Rats; Signal Transduction - drug effects; Tea; glucose transporter 4; skeletal muscle; insulin signaling pathway; acyl catechin
• DOI: 10.3390/ijms160716288
• ISSN: 1422-0067; 1661-6596

Tea catechins promote glucose uptake in skeletal muscle cells. In this study, we investigated whether the addition of an acyl group to the C-3 position of catechins to generate 3-O-acyl-catechins promoted glucose uptake in L6 myotubes. 3-O-Myristoyl-(−)-epicatechin (EC-C14) and 3-O-palmitoyl-(−)-epicatechin (EC-C16) promoted glucose uptake and translocation of glucose transporter (GLUT) 4 in the cells. The effect of 3-O-acyl-(−)-epicatechins was stronger than that of (−)-epicatechin (EC), whereas neither 3-O-myristoyl-(+)-catechin (C-C14) nor 3-O-palmitoyl-(+)catechin (C-C16) promoted glucose uptake or GLUT4 translocation as well as (+)-catechin (C). We further investigated an affinity of catechins and 3-O-acyl-catechins to the lipid bilayer membrane by using surface plasma resonance analysis. Maximum binding amounts of EC-C16 and C-C16 to the lipid bilayer clearly increased compared with that of (−)-EC and (+)-C, respectively. We also examined the mechanism of GLUT4 translocation and found EC-C14 and EC-C16 induced the phosphorylation of PI3K, but did not affect phosphorylation of Akt or IR. In conclusion, the addition of an acyl group to the C-3 position of (−)-EC increases its affinity for the lipid bilayer membrane and promotes GLUT4 translocation through PI3K-dependent pathways in L6 myotubes.