Cell Membrane Chromatography with Zonal Elution for Characterization of Seven Alkaloids Binding to α1A Adrenoreceptor

A high expression α1A adrenoreceptor (α1AAR) cell membrane chromatography (CMC) combined with zonal elution method was developed to study the affinity interaction between the three kinds of alkaloid in Lotus Plumule and four kinds of alkaloid in Uncaria rhynchophylla with the α1AAR. HEK293 α1AAR cells were used for preparation of the CMC stationary phase. All measurements were performed with diode array detector at 37°C. In the self- and direct-competitive displacement assay, tamsulosin was used as competitor to evaluate the effects of the competitor’s concentration on the retention factor and the seven kinds of alkaloid, respectively. The competition behavior between tamsulosin and the seven alkaloids were also been examined. The results indicated that tamsulosin and other seven alkaloids had the same affinity sites on α1AAR. The association equilibrium constants (KA) values obtained were (2.99 ± 0.41) × 105 L/mol for tamsulosin, (6.26 ± 1.22) × 105 L/mol for liensinine, (7.59802 ± 1.81918) × 105 L/mol f...