NEWBOULDIA LAEVIS LEAF FACILITATES INSULIN SECRETION, GLUCOSE UPTAKE AND PANCREATIC FUNCTION IN ALLOXAN-INDUCED HYPERGLYCAEMIA IN WISTAR RATS

The antihyperglycaemic activity of aqueous leaf extract of Newbouldia laevis (ALENL) was evaluated in rats. Twenty-five rats of both sexes (120 – 160 g) were divided into five groups (A-E) of 5 animals each. Group A (control) rats were administered 0.5 ml of distilled water (DW) orally while those in group B received 100 mg/kg body weight of ALENL. Animals in groups C, D and E which induced into hyperglycaemia (intraperitoneal administration of 150 mg/kg body weight of alloxan) were also administered DW, 100 and 200 mg/kg body weight of ALENL respectively, once daily for 14 days. Blood glucose levels (BGL) were determined at an interval of two days. Alloxan significantly (p<0.05) increased BGL in the DW treated hyper-glycaemic animals (DWTHA) from 48.00 ± 1.79 to 142.80 ± 2.35 mg/dl after 24 h. After two days, administration of the extract at 100 and 200 mg/kg body weight increased blood glucose level, but this increase was not statistically significant (p>0.05) when compared with the DWTHA. On day 4, the extract at both doses decreased blood glucose level, but this decrease was not statistically significant (p>0.05) when compared with the DWTHA. On days 6, 8, 10, 12 and 14, the extract at both doses decreased blood glucose level, but this decrease was statistically significant (p<0.05) when compared with the DWTHA. The study indicates that the extract at both doses possesses antihyperglycaemic properties which may have acted by stimulating glucose utilization by peripheral tissues or increasing insulin production by the pancreas from regenerated β-cells.