<i>In vitro</i> Antidiabetic Activity and Sub-chronic Toxicity Profile of Ethanol Extract of <i>Tephrosia bracteolata</i> Leaves

Abstract

Tephrosia bracteolata Guill. & Perr. (Fabaceae) has been used crudely in Nigeria for the treatment of diabetes. This study was carried out to  determine the antidiabetic activity, possible mechanism of action through the inhibition of the activities of α-amylase and α- glucosidase, and also to establish its safety. Sub-chronic toxicological studies involved distributing Wistar rats into 4 groups of 6 rats each.  Group one served as control and received 5 mL/kg distilled water while groups 2 to 4 received 500, 1000 and 2000 mg/kg of ethanol  extract of Tephrosia bracteolata (EETB) respectively for 30 days. Food and water intake, and body weight of the rats were monitored for 30 days after which, the rats were sacrificed and blood samples collected for biochemical and haematological analysis. The  organs were also harvested for histopathological examination. EETB exhibited concentration-dependent inhibitory effects on both α- amylase and α-glucosidase. The extract had IC₅₀ values of 92.76 and 71.09 μg/mL for α- amylase and αglucosidase respectively. These  values were higher than that of the standard drug - acarbose which had IC₅₀ values of 83.13 and 64.58 μg/mL for α-amylase and α- glucosidase respectively. The subchronic toxicity revealed that EETB had no significant (p > 0.05) effects on the biochemical and haematological parameters, and the organs of the rats. Based on these findings, it can be suggested that EETB has antidiabetic activity  and possible mechanism of action through the inhibition of αamylase and α-glucosidase enzymes. It can also be accepted that is safe due  to anecdotal reports.