α-Glucosidase inhibitors derived from black soybean and their inhibitory mechanisms

作者：Zheng, Yu; Zhang, Ruifen; Huang, Fei; Cheng, Lai-Hoong^*; Xu, Liangxiong^*; Jia, Xuchao^*

来源：Food Science and Technology, 2023, 189: 115502.

DOI：10.1016/j.lwt.2023.115502

• Black soybean
• Isoflavone
• alpha-glucosidase
• Affinity ultrafiltration
• Molecular docking

Various studies have documented the beneficial effects of black soybean extract against diabetes. However, the specific active compounds responsible for these effects remain elusive. Here, we aimed to identify the alpha-glucosidase inhibitors present in black soybeans using affinity ultrafiltration. Seven isoflavones with alpha-glucosidase inhibitory activity were identified, among which daidzein and genistein demonstrated remarkably superior inhibitory activity compared to that of acarbose (IC50 = 632.5 +/- 70.0 mu mol/L), exhibiting IC(50 )values of 15.7 +/- 0.3 and 3.2 +/- 1.2 mu mol/L, respectively. An analysis of the structure-activity relationship revealed a negative correlation between the degree of glycosylation of isoflavone and alpha-glucosidase inhibitory activity. Enzyme kinetic studies revealed that both daidzein and genistein acted as uncompetitive inhibitors of alpha-glucosidase. Additionally, these compounds effectively suppressed the intrinsic fluorescence of alpha-glucosidase through the static quenching mechanism. The interaction between daidzein or genistein and alpha-glucosidase involves spontaneous formation of a complex, which is driven by hydrophobic interactions and hydrogen bonds. These findings provide valuable insights into the molecular mechanisms underlying the alpha-glucosidase inhibitory acof black isoflavones.

• 单位
  广东省农业科学院; 惠州学院