Characterization of Compounds Acting on the α1A Adrenergic Receptor from Caulis spatholobi by Cell Membrane Chromatography with Possible Application for Treatment of Benign Prostatic Hyperplasia

Tamsulosin hydrochloride is a commonly used drug for treatment of benign prostatic hyperplasia which is a disease affecting elderly men. However, adverse reactions may occur when tamsulosin hydrochloride is used for long-term treatment. Caulis spatholobi is a traditional Chinese medicine with many pharmacological effects. In this study, a cell membrane chromatography column was combined with high-performance liquid chromatography-mass spectrometry to determine the active compounds acting on α1A adrenergic receptor from Caulis spatholobi. Formononetin was shown to be active on the α1A adrenergic receptor. This was investigated by a competitive binding assay that demonstrated that tamsulosin hydrochloride and formononetin employ the same binding sites. Thus, formononetin is a potential α1A adrenergic receptor antagonist for treating benign prostatic hyperplasia.