ObjectiveThis study investigated the improvement of the polyphenol from the fruit of Viburnum sargentii (PVSK) on insulin resistance (IR) model of HepG2 cells, and to evaluate its hypoglycemic activity.

MethodHigh concentration insulin was used to induce in vitro IR model, and the stability (cell activity method) and reliability (Z factor method) of the model were evaluated. Blank group, IR model group, positive control group (metformin) and PVSK group were set up. Cell viability was detected by MTT assay, glucose content in culture medium was detected by Glucose oxidase method and the consumption of glucose was clculated; glycogen content was determined by anthrone method; the activity of hexokinase (HK) and pyruvate kinase (PK) were determined by colorimetric method. Enzyme-linked immunosorbent assay (ELISA) was used to detect the activity of phosphoenolpyruvate kinase (PEPCK) and glucose hexaphosphatase (G6PC).

ResultInsulin induction treatment of HepG2 cells at 10^{− 6} mol/L for 24 hours was the best condition for the production of insulin resistance model, and the IR model had high stability and reliability within 12 ~ 36 hours. 0.10 ~ 1.00 mg/mL PVSK polyphenol group had significantly higher glucose consumption than model group (P < 0.05). The highest glucose consumption was (3.49 ± 0.11) mmol/L in 24 h and 0.50 mg/mL groups, with a consumption rate of 88.81% (P < 0.01). Comparedwith model group, PVSK polyphenols could increase glycogen content by 33.65% (P < 0.01), HK and PK activity by 43.36% (P < 0.05) and 48.41% (P < 0.01), respectively. The inhibition rates of G6PC and PEPCK activity were 22.86% (P < 0.01) and 17.33% (P < 0.05), respectively.

ConclusionPVSK could increase HK and PK activities of IR-HepG2 cells, accelerate glycolysis and increase glycogen content. Inhibiting the activity of G6PC and PEPCK can reduce the production of endogenous glucose. Therefore, the polyphenols of PVSK have a certain effect on the treatment of insulin resistance cells.