The effect of the aqueous stem bark extract of Kokoona zeylanica Thw. on the blood glucose level of mice

This study examined the blood glucose lowering potential of the aqueous stem bark extract (ABE) of Sri Lankan endemic plant - Kokoona zeylanica (Family: Celestraceae). This was tested in normoglycaemic mice using three oral doses (1800, 2500 and 3000 mg/kg of body weight). The results show a moderate but dose dependant acute hypoglycaemic activity with a fairly rapid onset (4 h). However, it did not have a hypoglycaemic effect in non fasted mice or in fasted mice (treated consecutively for 30 days). ABE did not improve the glucose tolerance test indicating the lack of antihyperglycaemic activity. However, ABE improved the sucrose tolerance test indicating the α-glucosidase inhibitory activity, which appears to be the main mechanism of hypoglycaemic activity. ABE was well tolerated (in terms of overt clinical signs of toxicity, hepatotoxicity and renotoxicity), and it did not provoke a change in the lipid profile. It is concluded that the ABE of K. zeylanica has a safe, moderate and acute hypoglycaemic activity