Abstract: Objective: To observe the effect of tartary buckwheat (FagoPyrum tataricum Gaertn.) albumin hydrolysate (TBAH) on insulin resistance in HepG2 cells. Methods: TBAH, prepared with alkaline protease, was ultrafiltrated to retain peptides with molecular mass less than 3 kDa. HepG2 cells were induced by high glucose and high insulin for 36 h to establish an insulin resistance model. Then, the cells were cultured with 2.5, 5 and 10 μg/mL TBAH for 24 h. The effect of TBAH on glucose metabolism in HepG2 cells was observed. The effects on oxidative damage indicators nitric oxide (NO), malondialdehyde (MDA), lactic dehydrogenase (LDH), superoxide dismutase (SOD), reactive oxygen species (ROS) and the insulin receptor substrate 1 (IRS-1)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway in insulin-resistant HepG2 cells were also detected. Results: Compared with the insulin resistance model group, glucose consumption in the TBAH group was significantly increased (P < 0.05) in a dose-dependent manner, while MDA, NO and ROS contents were significantly decreased (P < 0.01, P < 0.05); SOD activity was significantly increased (P < 0.05), whereas LDH activity was significantly decreased (P < 0.05); Phosphorylated IRS-1 protein expression level was decreased (P < 0.05), whereas phosphorylated Akt, PI3K and glucose transporter 4 protein expression levels were significantly increased (P < 0.01). Conclusion: TBAH can improve insulin resistance by inhibiting oxidative stress.

Key words: tartary buckwheat albumin hydrolysate; HepG2 cells; insulin resistance; oxidative stress; insulin signaling pathway