A combined cell membrane chromatography and online HPLC/MS method for screening compounds from Radix Caulophylli acting on the human α_1A-adrenoceptor

We have developed an online analytical method that combines α_1A-adrenoceptor (α_1AAR) cell membrane chromatography (α_1AAR-CMC) with high performance liquid chromatography and mass spectrometry (HPLC/MS) for the identification of active components from Radix Caulophylli acting on the human α_1AAR. Fractions retained by the α_1AAR-CMC column were captured into a loop and the components were directly analyzed by combining an 8 port column switcher with an HPLC/MS system for separation and preliminary identification. Using methoxamine as a positive control drug, magnoflorine and caulophine from Radix Caulophylli were identified as the active molecules acting on the α_1AAR. This new α_1AAR-CMC-online-HPLC/MS method can be applied for screening active components acting on α_1AAR from traditional Chinese medicines exemplified by Radix Caulophylli. This method will be of great utility in drug discovery using natural medicinal herbs as a source of novel compounds.