ANTIDIABETIC ACTIVITY OF THE AQUEOUS EXTRACTS OF SARCOCEPHALUS POBEGUINII (BARKS) AND NAUCLEA DIDERICHII (LEAVES AND BARKS) IN NORMAL AND STREPTOZOTOCIN INDUCED-HYPERGLYCEMIC RATS.

Abstract

Nauclea diderrichii (barks and leaves) and Sarcocephalus pobeguinii (barks) used in Gabonese traditional medicine for the management of diabetes have been shown to be potent inhibitor of α-glucosidase. The present study was aimed to evaluate the antidiabetic activity of the aqueous extract of these plants in normal and streptozotocin induced-diabetic rats. Effect of various doses (50-400 mg/kg) of extract was studied on their hypoglycemic activity. Two effective doses were selected to investigate their antidiabetic effect on streptozotocin induced-diabetic rats. Animals received substances at a unique daily dose for two weeks. Blood glucose levels were determined weekly. Several others parameters were evaluated: lipid profile, serum transaminases, total proteins, creatinin, total and direct bilirubin and uric acid. Some oxidative parameters were also measured. In normal rats, all extract reduced blood glucose levels with a marked effect at the dose of 200 mg/kg with Nauclea diderrichii bark. In diabetic rats, Nauclea diderrichii leaf extract (100 mg/kg) brought the blood glucose levels towards normal value and maintained it at the 2 nd week. At the dose of 200 mg/kg, the glycaemia returned to the normal value after two weeks post-administration. The administration of streptozotocin induced abnormalities in lipid profile, transaminases, creatinemia and parameters of oxidative stress. Administration of plant extracts improved lipid profile, liver function and antioxidant status of rats. Nauclea diderrichii leaf extract was the most potent extract than Sarcocephalus pobeguinii and Nauclea diderrichii bark extracts. Thus it is concluded from this study that, Nauclea diderrichii aqueous leaves possess a marked potential-antidiabetic activity than other extracts.