Hypoglycemic effects of Fu-Pen-Zi (Rubus chingii Hu) fruit extracts in streptozotocin-induced type 1 diabetic mice

• FPZ alleviated hyperglycemia in STZ-induced diabetic mice. • FPZ increased antioxidant response and protected pancreatic islet against STZ-induced damage. • FPZ inhibited Atrogin-1 and Trim63 expression and prevented muscle atrophy. To explore the effects of Chinese raspberry (Fu-Pen-Zi) on diabetes, a polyphenol-enriched extract (FPZ) was prepared. Streptozotocin (STZ)-induced diabetic mice were daily administered FPZ (30 mg/kg body weight) for 18 days, the anti-diabetic effects were evaluated. Compared to STZ alone mice, FPZ-treatment ameliorated STZ-induced type 1 diabetes, reduced body weight loss (by 71.61%), hyperglycemia (fasting blood glucose reduced by 19.23%), hyperlipidemia (hepatic triglycerides reduced by 15.50%) and skeletal muscle atrophy (quadriceps mass increased by 21.46%). FPZ protected pancreatic β-cells from STZ-induced damage and promoted insulin secretion, preserved insulin signaling in liver tissues and skeletal muscles. FPZ improved glucose tolerance, modulated liver glycogen metabolism, and inhibited hepatic gluconeogenesis via activating insulin/Akt/Gsk3β and LKB1/AMPK signaling. Moreover, FPZ reduced liver oxidative stress and steatosis, reduced Atrogin-1 and Trim63 expression, contributes to muscle atrophy inhibition. This study highlights the potential usage of FPZ as nutritional interventions for type 1 diabetes and muscle atrophy management.