Discovering the Bioactive Compounds Binding to α1A-Adrenergic Receptor in Guizhi Fuling Formula and Revealing Their Interactions by Immobilizing the Receptor Through Colicin L7 DNase/Immunity Protein 7 Ultra-Affinity System

In this work, Guizhi Fuling Formula (GFF), as well as α_1A-adrenergic receptor (α_1A-AR) were taken as the research objects. By utilizing the ultra-affinity between Colicin L7 DNase (CL7) and its homologous immune protein 7 (Im7), CL7-tagged α_1A-AR was oriented immobilized to the Im7-coated silica gel surface. With the α_1A-AR immobilized column in hand, the active compounds in GFF targeted to α_1A-AR were screened, and the binding procedures were analyzed. The composite characterization demonstrated that the α_1A-AR can be immobilized to the chromatographic stationary phase with good specificity and stability in 3 weeks. Paeoniflorin, cinnamic acid, and paeonol were identified as the active compounds in GFF targeted to α_1A-AR. Among them, cinnamic acid and paeonol have the same binding site on α_1A-AR as the specific drug tamsulosin. The binding parameters obtained by frontal analysis and injection amount-dependent analysis were consistent in the same concentration range. Collectively, these results indicated that the α_1A-AR chromatographic column synthesized by a novel immobilized method was capable of screening and analyzing the functional compounds from the complex matrix, which provided an alternative for rapid screening and analysis to traditional ethnic drugs.