The Phosphorylation of IRS1^S307 and Akt^S473 Molecules in Insulin‐Resistant C2C12 Cells Induced with Palmitate Is Influenced by Epigallocatechin Gallate from Green Tea

Abstract

In the current investigation, the effect of epigallocatechin gallate (EGCG) on the phosphorylation of IRS1S307 and AktS473 molecules in insulin‐resistant C2C12 muscle cells induced with palmitate was studied and compared with the effect of the antidiabetic drug, rosiglitazone. C2C12 myoblasts were cultured in Dulbecco's modified Eagle's medium and differentiated into myotubes using horse serum and the creatine kinase test was used to confirm their differentiation. The treatment of C2C12 myotubes was carried out with palmitate, where albumin was used as the conjugator. The Western blot technique was used to check the useful phosphorylation of IRS1S307 and AktS473 in C2C12 myotubes, in the presence or absence of palmitate. There was a significant (p < 0.00) and linear increase in the activity of creatine kinase over time (0 to 96 h after differentiation) with everyday myoblast formation. While neither EGCG nor rosiglitazone showed a significant (p > 0.05) effect on palmitate content during 96 h of incubation of IRS1S307, EGCG alone or combined with rosiglitazone increased the phosphorylation of AktS473, leading to the increase of glucose uptake into C2C12 cells. Thus, it can be concluded that EGCG alone or in combination with rosiglitazone may show some therapeutic effects for the prevention or treatment of Type 2 diabetes owing to its substantial effect on increasing the phosphorylation of AktS473 and the subsequent glucose uptake into the cells.

Therapeutic Activity of Green Tea Epigallocatechin-3-Gallate on Metabolic Diseases and Non-Alcoholic Fatty Liver Diseases: The Current Updates

“…According to Lee et al [61] green tea-derived products such as extracts and water-soluble polysaccharides exhibit hypoglycemic effects as they caused delayed intestinal absorption of glucose. The hypoglycemic mechanism of EGCG has been contributed by its inhibitory effect on α-glucosidase activity, enhancement of glucose uptake, and promotion of glucose transporter-4 (GLUT4) translocation to the plasma membrane through a phosphatidylinositide-3-kinase/activated protein kinase B (PI3K/AKT) signaling pathway in skeletal muscle cells [62,63]. When EGCG uptake was combined with regular exercise in overweight or obese postmenopausal women, it resulted in reduced plasma glucose concentration in subjects with impaired glucose tolerance [64].…”

Mechanisms Underlying the Effects of the Green Tea Polyphenol EGCG in Sarcopenia Prevention and Management

“…192,193 EGCG has been reported to decrease serum troponin T levels and DNA damage induced in rats 194 and reduce troponin T concentrations in the pulmonary artery and the mitochondrial structure in vitro. 195 EGCG is highly effective in increasing the activity of creatine kinase in vitro 40,196 and in aged mice. 197 From senescent mice, as an apoptosis cell death program, cytochrome C release rates in skeletal muscle cell with mitochondrial dysfunction were 3.5-fold higher than in young mice.…”