黑豆含硒肽对α-淀粉酶的抑制作用及其体外降血糖活性OA

This study investigated whether selenium-containing peptides derived from selenium-rich black beans exert inhibitory effects on α-amylase and evaluated their potential hypoglycemic activity in vitro.Selenium-rich black beans from Guangxi,China,were used as raw materials,and selenium-containing peptides were screened and synthesized through a combination of single-factor experiments,response surface methodology,and peptidomics analysis.Four peptides—Se-MetLP,Se-MetIP,TLTSe-MetLR,and Se-CPSFGQ—were identified and evaluated for their α-amylase inhibitory activity.Among the four peptides,Se-MetIP exhibited the highest inhibitory effect,achieving an inhibition rate of 70.58%±2.21%at a concentration of 4 mg/mL,whereas TLTSe-MetLR showed the lowest half-maximal inhibitory concentration(IC50)of 0.47 mg/mL,indicating superior inhibitory potency.Based on their strong α-amylase inhibitory activity,Se-MetIP and TLTSe-MetLR were selected for further investigation of inhibition mechanisms using circular dichroism spectroscopy,isothermal titration calorimetry,and molecular docking analyses,and their in vitro hypoglycemic effects were subsequently evaluated in a hyperglycemic HepG2 cell model.Circular dichroism analysis revealed that peptide binding induced conformational changes in α-amylase,characterized by increased β-sheet content and reduced β-turn and random coil structures,suggesting alterations in the enzyme spatial conformation.Isothermal titration calorimetry demonstrated that peptide-enzyme interactions were exothermic.Molecular docking results showed that the binding free energies of Se-MetIP and TLTSe-MetLR with α-amylase were-5.399 and-6.401 kcal/mol,respectively,with van der Waals forces and hydrogen bonding as the dominant stabilizing interactions,complemented by hydrophobic effects.Furthermore,cellular assays demonstrated that Se-MetIP and TLTSe-MetLR significantly enhanced glucose consumption and promoted glycogen synthesis in insulin-resistant HepG2 cells,thereby improving glucose utilization.Overall,selenium-containing peptides from black beans effectively inhibit α-amylase activity and exhibit in vitro hypoglycemic potential,providing a theoretical basis for the development of hypoglycemic peptides from selenium-rich black beans.