This study investigated the anti-diabetic effect of cyanidin-3-O-glucoside (C3G), an anthocyanin extracted from red bayberry. In vitro experiments using insulin-resistant HepG2 and L02 cells showed that C3G increased glucose consumption, glycogen synthesis, and insulin sensitivity by inhibiting protein tyrosine phosphatase 1B (PTP1B) and increasing phosphorylation of insulin receptor substrate 2 (IRS-2). In vivo studies using diabetic db/db mice demonstrated that C3G administration reduced fasting blood glucose levels and improved glucose tolerance and insulin resistance. These findings suggest that C3G may be a potential therapeutic agent for type 2 diabetes mellitus.
