Volume 14, Issue 34, July - December, 2020

Effects of Polyalthia longifolia leaves against streptozotocin-nicotinamide induced type 2 diabetes mellitus and peripheral neuropathy in rats

Andichettiar Thirumalaisamy Sivashanmugam, Tapan Kumar Chatterjee^♦

Division of Pharmacology, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India

^♦Corresponding author
Dr. T. K. Chatterjee, Division of Pharmacology, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India; E-mail: tkchatterjee_81@rediffmail.com

ABSTRACT

Polyalthia longifolia (Sonner.) Thw. (Annonaceae) has been used in Ayurveda for treating fever, skin diseases, diabetes, hypertension and helminthiasis. This study evaluates the protection against type 2 diabetes and diabetic neuropathy by Polyalthia longifolia leaves. Streptozotocin-nicotinamide-induced type 2 diabetes in rat model was used. The diabetic animals were treated with the ethanol extract (PLEE) or chloroform (PLCE) extracts at two dose levels (100 and 200 mg/kg) or standard, glibenclamide (5 mg/kg) for 28 days. Diabetic neuropathy was tested by radiant heat tail-flick method. In diabetic rats the fasting blood glucose levels increased upto 296.3 ± 4.4 mg/dL which decreased to 107.5 ± 4.1 mg/dL (PLEE) and 126.3 ± 4.2 mg/dL (PLCE) at 200 mg/kg dose level. The triglycerides, total cholesterol, LDL and serum marker enzymes were elevated and HDL levels were decreased in diabetic animals and were reversed to near normal values upon treatment with extracts. The levels of enzymatic and non-enzymatic antioxidants were reduced in diabetic animals where as treatment with extracts reversed the same. Histopathological study reflected partial damage of islets of Langerhans in diabetic animals and regeneration of islets in extract- and glibenclamide-treated diabetic animals. The latency of tail flick in analgesiometer was 3.2 ± 0.3 sec in diabetic rats which increased to 10.9 ± 0.3 sec (PLEE) and 9.4 ± 0.4 sec (PLCE). The extracts showed good antidiabetic activity and protection against diabetic neuropathy. Thus, Polyalthia longifolia makes a good candidate for continued exploration in this regard.

Keywords: Analgesiometer, liver enzymes, antioxidants, histopathology

Drug Discovery, 2020, 14(34), 217-230

PDF