Abstract

IN VIVO ASSESSMENT OF ANTIHYPERGLYCEMIC AND ANTIDIABETIC ACTIVITIES OF THE AQUEOUS EXTRACT FROM THE STEM BARK OF ALSTONIA CONGENSIS ENGL. (APOCYNACEAE) AND ITS FRACTIONS IN NORMAL AND STREPTOZOCIN-INDUCED DIABETIC WISTAR RATS.

Nsaka Lumpu, S., Tshodi Ehata, M., Mbamu Maya, B., Kikweta Munduku, C., Bakana Phongi, D., Kambu Kabangu, O., Cimanga Kanyanga, R.*,

ABSTRACT

The aqueous extract from Alstonia congensis stem bark and its fractions were studied for their potential antihyperglycemic and antidiabetic properties in normal and streptozocin-induced diabetic Wistar rats respectively. Results indicated that the oral administration of the aqueous extract and its fractions at variable doses of 100, 200 and 400 mg/kg bodyweight showed significant blood glucose lowering in normal rats (< 85 mg/dl) compared to negative normal control (86 ± 0.5 mg/dl) and in diabetic treated animals (< 180 mg) compared to non-treated diabetic rats (228.3 ± 1.2 mg/dl) in dose-dependent manner after 7h of treatment. But the glycaemia of treated diabetic rats still remained high requiring particular treatment. Thus, after 21 days of treatment, the administration of the aqueous extract and its fractions at the highest oral dose of 400 mg/kg, reached significant reduction of glycaemia in untreated diabetic rats (< 100 mg/dl) compared to diabetic control group (> 250 mg/ml). In the oral glucose tolerance test, the aqueous extract and its fractions showed a marked decrease of the concentration level of the glucose in hyperglycemic rats in dose-dependent manner (< 110 mg/dl) compared to negative control group (> 160 mg/dl) after 1h30’ of treatment. Glibenclamide used as reference product showed high antihyperglycemic and antidiabetic activities compared to A. congensis stem bark samples. Results reported in the present study, clearly show that A. congensis stem bark samples possess antihyperglycemic and antidiabetic properties and are able to ameliorate the diabetic state, and probably can be considered as a new source of antihyperglycemic and antidiabetic agents. They constitute a scientific base supporting and justifying the traditional use of A. congensis stem bark for the treating of type 2-diabetes mellitus in traditional medicine in Democratic Republic of Congo and other African countries.

Keywords: Alstonia congensis, stem bark, aqueous extract, antihyperglycemic and antidiabetic activities.