PHYTOCHEMICAL SCREENING, ANTIOXIDANT AND HYPOGLYCEMIC ACTIVITY OF COCCOLOBA UVIFERA LEAVES AND WALTHERIA INDICA ROOTS EXTRACTS

Abstract

Objective : Coccoloba uvifera (Polygonaceae) and Watheria indica (Sterculiaceae) are two medicinal plants used in Togolese traditional medicine to treat diabetes mellitus. The present study was designed to evaluate their antioxidant properties and hypoglycemic activity. Methods : After phytochemical screening, hydro alcoholic leaves extracts of Coccoloba uvifera and the hydro alcoholic roots extract of Watheria indica were evaluated on blood glucose levels in fasting normal and glucose loaded hyper glycemic rats (oral glucose tolerance test). Antioxydant activities were performed using AAPH (2, 2’-Azobis 2 Amidino propane Dihydrochloride test and nitric oxide radical scavenging activity). Results : Phytochemical tests revealed the presence of flavonoids, total phenols and tanin in the hydro alcoholic extracts of C. uvifera and W. indica . The hypoglycemic activity measured after oral administration of glucose (2 g/kg) revealed that W. indica leaves and C. uvifera roots induced a significant reduction of hyperglycemia in treated group compared to control group. There was a significant reduction in the hyperglycemic peak with W. indica leaves extract at doses of 250 mg/kg (p<0.05) and 500 mg/kg (p<0.001). Moreover, the administration of extracts (at dose of 500 mg/kg) in fasted rats did not show any significant decrease in basal blood glucose level compared to the control. Hydro alcoholic extracts inhibit hemolysis of erythrocytes induced by AAPH dose-dependent manner and have an antioxidant power comparable to that of the Butylated Hydroxy Toluene (reference drug). The extracts inhibit the production of nitric oxide and possess reducing power. Conclusion : The results of this study support the use of these plants in the treatment of diabetes in Togolese traditional medicine.