Abstract

ANTIDIABETIC ACTIVITY OF CLERODENDRUM PHLOMIDIS Linn. AND GYMNEMA SYLVESTRE Linn. IN ALLOXAN INDUCED DIABETIC RATS - A COMPARATIVE PRECLINICAL STUDY

S. Gopinathan * and D. Naveenraj

Abstract

The present study was aimed to evaluate the antidiabetic potential of Clerodendrum phlomidis leaf extract and compare its efficacy with Gymnema sylvestre leaf extract, a known antidiabetic herbal drug and a standard reference drug, Glibenclamide on alloxan induced diabetic rats. The rats were divided into five groups and treated accordingly; Group I: Normal healthy control rats; Group II: Disease control- Alloxan induced diabetic rats; Group III: Diabetes induced rats treated with Clerodendrum phlomidis leaf extract; Group IV: Diabetes induced rats treated with Gymnema sylvestre leaf extract; Group V: Drug control rats - diabetes induced animals treated with Glibenclamide. Oral administration of plant extracts on alloxan induced diabetic rats showed a marked decrease in the levels of biochemical parameters such as blood glucose, liver glycogen and glycosylated hemoglobin. The levels of blood urea and serum creatinine were also brought to normal levels in the rats treated with plant drugs. The activity of glycogen synthase was reduced and the activities of glycogen phosphorylase, glucose-6-phosphatase, glucose-6-phosphate dehydrogenase were increased in diabetic rats. Profound alteration was observed in lipid profiles (total cholesterol, triglycerides, free fatty acids and phospholipids). Levels of lipoproteins (HDL, LDL and VLDL) showed a significant impairment in diabetic rats which were brought back to normal in plant drug treated and standard drug treated rats. Serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) and alkaline phophatase (ALP) activities were increased in diabetic rats. The treatment with plant drugs brought back to normalcy of these enzymes. Reduced glutathione and lipid peroxidation levels were increased in thediabetic condition and significantly increased after the plant drug treatment. The activity of catalase was reduced in the diabetic rats and the activity was normalized after plant drug administration. The present study evidenced that Clerodendrum phlomidis leaf extract is a potent antidiabetic herbal drug and its efficacy is comparable to Gymnema sylvestre leaf extract and Glibenclamide. Ursolic acid (a pentacyclic triterpenoid carboxylic acid) was isolated and identified as pharmacologically active compound in Clerodendrum phlomidis leaf extract.

Keywords: Diabetes mellitus, antidiabetic activity, Clerodendrum phlomidis, Gymnema sylvestre, ursolic acid, animal study.