Comparative study of antihyperglycaemic activity of urticadioica (stinging nettle), zadirachta indica (neem) and aloe secundiflora (aloe) extracts on rabbits and streptozotocin induced diabetic rats

Abstract

The prevalence of type 2 diabetes is increasing in developing, as well as other countries. Searching for hypoglycaemic agents with origin from domestic herbals was considered a useful and promising way to find novel therapy of the disease. This study was designed to investigate the antihyperglycaemic potential of Aloe secundiflora, Urtica dioica and Azadirachta indica leaves and assess various dose-response effects in the rabbit and diabetic Wistar rats. Shadow dried and powdered A. indica and U dioica leaf were extracted using 60% ethyl alcohol (1:3 w/v). Dried A. secundiflora leaf sap juice was concentrated in an open vessel. Their formulation mode was improved by constituting syrup. Diabetes was induced by a single i.p streptozotocin injection (50 mg/kg). Graded doses of the extracts and placebo were orally administered to normoglycaemic rabbits for 4 weeks. In oral glucose tolerance test male Wistar rats were administered glucose (3g/kg b.w) 210 min after oral administration of extracts (80 mg kg -I). 80 mg kg -\ b.w of the extracts was administered orally to diabetic rats for 6 weeks. Control animals were given glibenclamide and placebo. Blood samples were evaluated using a glucose oxidase kit, (Human, Wiesbaden Germany). At the end of 6 weeks, the rats were sacrificed by anaesthesia, whole pancrease and kidney extracted, weighed, fixed in Bouin's solution and stained by hematoxylin -eosin dye. There was noticeable reduction in blood glucose levels after chronic administration of A. indica and U dioica extract at 10,20,40 and 80 mg kg -\ in normoglycaemic rabbits. A. secundiflora did not show any effect at these doses. 100 mg kg -\A. indica and U dioica extracts had statistically significant effect, p< 0.05 against the control. Animals fed on A. secundiflora had decreased appetite and experienced loose stool. In OGrr model the blood glucose levels of groups fed on A. secundiflora, U dioica and A. indica were p<O.OOl, p<O.OOl and p<0.05 respectively compared to control group at 120 min. A. secundiflora, U dioica and A.indica leaf extracts also produced a significant decrease in glucose level (p< 0.05) of diabetic-treated compared with diabetic controls. In segment jejunum the percentage fall in glucose concentration of the medium with initial values was 27.7% for A. secundiflora, 31.6% A. indica and 36.0% for U dioica against 43.8% for the control during 2 hours. The results indicate that A. secundiflora, A. indica and U dioica are potential antihyperglycaemics and can be used in modulating blood glucose levels