Antidiabetic effect of combined aqueous leaf extract of vernonia amygdalina and metformin in rats.

This study investigated the antidiabetic activity of the various combinations (ratios) of metformin (50 mg/kg) and aqueous extracts of the leaves of Vernonia amygdalina (100 mg/kg). The ratios of Extract to Metformin were 1:1, 2 1, and 2:1 and distilled water (control, p.o.) were given to both normoglycemic and alloxan-induced diabetic Wister albino rats. Blood was withdrawn and tested at 0, 1, 3 and 6 hours. Results showed that the combinations of the extract and metformin caused more reduction in glycemia compared to any of the agents acting alone in either of the two categories of animals. The ratio of 1:2 caused the most significant (p%0.05) reduction in blood sugar (-66.07%) compared to distilled water (-7.2%). However, the ratio of metformin: extract (2:1) caused a reduction of -62.66% but was found a better combination considering the safety of the drugs. The combination of Vernonia amygdalina with metformin for the management of diabetes should be highly encouraged with a reduction in the dose of metformin and an increase in the dose of the plant extract to guarantee efficacy and safety.