Regulation of carbohydrate metabolism and insulin secretion in diabetic rats following treatment with Hypericum perforatum L. hairy root aqueous methanol extract

Abstract

Hairy root (HR) cultures of Hypericum perforatum L. have shown promise in controlling hyperglycemia, regulating blood lipid and enzyme profiles, and improving metabolic function in vivo. These benefits are mainly attributed to the phenolic acids, flavonoids, and xanthones present in HR extracts. However, the specific mechanism underlying these effects remains unclear. This study was performed to elucidate the biochemical and molecular mechanisms driving HR the antihyperglycemic and antidiabetic effects of HR extracts. HR extract (200 mg/kg body weight) was administered daily for 14 days to healthy rats and rats with streptozotocin-induced diabetes, with glibenclamide serving as a positive control. The phenolic composition of the HR extracts was confirmed through high-performance liquid chromatography/diode array detection/electrospray ionization mass spectrometry (HPLC/DAD/ESI-MSn ) analysis. The results showed that HR extract treatment increased the plasma insulin level and pancreatic poly (adenosine diphosphate-ribose) polymerase (PARP) activity in diabetic rats, thus normalizing blood glucose levels. Additionally, it reduced the activity of gluconeogenic enzymes, increased the activity of glycolytic enzymes, and normalized the glycogen content in the liver. HR extract-treated rats also exhibited increased hepatic adenosine monophosphate-activated protein kinase (AMPK) mRNA expression and a decreased protein kinase Cε (PKCε) concentration. In conclusion, HR extract demonstrated insulinotropic effects and effectively regulated hepatic carbohydrate metabolism in diabetic rats by modulating AMPK expression and the PKCε concentration. These findings suggest the potential use of HR extract as an herbal medicine for diabetes treatment and a source of antidiabetic drug development.