Abstract: Objective: To investigate the effects of respective combinations of three bioactive components from mulberry leaves including polysaccharides, flavonoids and alkaloids with metformin on the levels of blood glucose, glycogen, glucose tolerance in diabetic mice. Methods: A mouse model of experimental diabetes was established by intraperitoneal injection of streptozocin. Metformin alone or in combination with polysaccharides, flavonoids and alkaloids from mulberry leaves was intragastrically administered at a dosage of 100 mg/(kg ·d) once a day for 12 days to observe their effects on body weight and the levels of blood glucose and glycogen in diabetic mice. Results: Each of the three components from mulberry leaves could enhance the blood glucose-lowering effect of metformin in diabetic mice. Metformin plus mulberry leaf alkaloids exhibited the most powerful hypoglycemic effect, resulting in a 39.41% reduction in blood glucose level, which was increased by 5.13% when compared with metformin alone.

Key words: mulberry leaves, metformin, combined medication, hypoglycemic effect