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.