ABSTRACT
OBJECTI VE To explore the effects of total flavonoids of Bidens polisa L.(TFB)on insulin resistance (IR)of HepG2 cells. METHODS B. polisa L. was refluxed and extracted with 80% ethanol to obtain TFB. Palmitic acid was used to induce IR mode of HepG 2 cells in vitro . The effects of low-concentration ,medium-concentration and high-concentration (20,40, 80 mg/L) of TFB on the consumption of glucose were investigated. Using metformin as positive control ,the effects of low-concentration,medium-concentration and high-concentration (20,40,80 mg/L)of TFB on the protein expression of insulin receptor substrate- 1(IRS-1),c-Jun N-terminal kinase (JNK)and protein kinase C (PKC)were investigated. Molecular docking technology was used to explore the interaction between eight main active components of TFB such as quercetin ,quercitrin and IRS-1,JNK and PKC proteins. RESULTS The glucose consumption of TFB low-concentration ,medium-concentration and high-concentration groups were increased significantly (P<0.05 or P<0.01). Compared with normal group ,the expression of IRS-1 and JNK protein in the model group decreased significantly ,and the expression of PKC protein increased significantly (P< 0.01). Compared with model group ,the protein expression of IRS- 1 and JNK could up-regulated while the protein expression of PKC down-regulated in TFB low-concentration ,medium-concentration and high-concentration groups and metformin positive control group (P<0.05 or P<0.01). The score of molecular docking energy between maritimetin in TFB and IRS- 1 protein was -7.9 kcal/mol(1 kcal=4.816 kJ). The scores of molecular docking energy of maritimetin ,rutin and JNK protein were -9.3 kcal/mol. The score of molecular docking energy between quercitrin and PKC protein was -4.9 kcal/mol. Interactions between components and proteins included forming hydrogen bonds ,hydrophobic bonds and so on. CONCLUSIONS TFB can significantly improve IR of HepG 2 cells,the mechanism of which may be related to the regulation of protein expression of IRS ,JNK and PKC. Maritimetin,rutin and quercitrin may be potential active ingredients for improving IR.