Effects of Nelumbinis Receptaculum extract on insulin resistance in type 2 diabetic rats / 中草药

ABSTRACT

To study the effects of Nelumbinis Receptaculum (the seedpod of Nelumbo nucifera) extract (NRE) on insulin resistance (IR) in type 2 diabetic rats. The experimental type 2 diabetic rats were established by high-fat diet for 4 weeks and injected with low dose of streptozotocin (STZ, 30 mg/kg). After intervention by ig administration of NRE in low, medium, and high dose groups (100, 300, and 500 mg/kg) for 5 weeks, the effects of NRE on the levels of fasting blood glucose (FBG), fasting insulin (FINS), total cholesterol (TC), triglycerides (TG), high density lipoproteins cholesterol (HDL-C), low density lipoproteins cholesterol (LDL-C), the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and hexokinase (HK), the levels of liver glycogen, muscle glycogen, liver malondialdehyde (MDA), reduced glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), plasma leptin, and TNF-α were observed. The insulin sensitivity index (ISI) and IR were calculated accordingly. NRE could decrease the levels of FBG, increase ISI, reduce the levels of IR, plasma leptin, and TNF-α (P < 0.05 or P < 0.01) in type 2 diabetic rats. The dyslipidemia (TC, TG, HDL-C, and LDL-C) and hepatic metabolism (TC, TG, ALT, and AST) could be improved by NRE (P < 0.05 or P < 0.01). NRE could increase the GSH level and antioxidant enzymes activities, and decrease MDA level. In addition, NRE could increase the glycogens content and HK activity. NRE could improve the IR in the experimental type 2 diabetic rats. It might be related to its effects on improving dyslipidemia, hepatic metabolism, and antioxidant capacity of hepatic tissue, as well as reducing leptin and TNF-α levels.