[Differentiated hypoglycemic effects of baicalin, berberine and puerarin on insulin-resistance HepG2 cells]

To investigate the hypoglycemic effects of baicalin, berberine, puerarin and liquiritin on the insulin resistance (IR) cells. The IR model of HepG2 cells was established by treatment with insulin and dexamethasone for 48 h. Glucose uptake, glycogen content and cell viability were detected with different concentrations of baicalin, berberine, puerarin, liquiritin in IR-HepG2 cells. Compared with IR model group, all of intervened groups significantly increased the glucose consumption, except for liquiritin groups and 1 μmol·L⁻¹ baicalin group. Moreover, 10, 20, 50 μmol·L⁻¹ baicalin, 5, 10, 20, 50 μmol·L⁻¹ berberine and 40, 80, 160 μmol·L⁻¹ puerarin significantly elevated glycogen content in IR-HepG2 cells. Liquiritin did not show obvious hypoglycemic effect. Compared with normal group, the mRNA expression levels of GLUT1 and GLUT4 were decreased in IR-HepG2 cells according to qPCR results. 5, 20 μmol·L⁻¹ berberine decreased the mRNA expression level of GLUT1 in IR-HepG2 cells, whereas 20, 40, 80 μmol·L⁻¹ puerarin significantly elevated the mRNA expression level of GLUT1. Moreover, 10, 20, 50 μmol·L⁻¹ baicalin and 20 μmol·L⁻¹ berberine increased the mRNA expression level of GLUT4. Whereas, 40, 80 μmol·L⁻¹ puerarin decreased the mRNA expression level of GLUT4. Western blot results suggested that 10, 20, 50 μmol·L⁻¹ baicalin significantly increased the protein expressions of GLUT2 and GLUT4, whereas 20, 40, 80 μmol·L⁻¹ puerarin significantly up-regulated GLUT1 and GLUT2 proteins. In addition, 20 μmol·L⁻¹ berberine increased the protein expressions of GLUT2 and GLUT4, whereas 10 μmol·L⁻¹ berberine up-regulated GLUT4 expression. The results preliminarily suggested that baicalin, berberine and puerarin have differentiated hypoglycemic effects, which accelerate glucose transport, increase glycogen synthesis, regulate glucose metabolism and improve hepatic IR.