Rapid screening of bioactive compound in Sanzi Yangqin Decoction and investigating of binding mechanism by immobilized β2-adrenogic receptor chromatography coupled with molecular docking.

Screening bioactive compounds from traditional Chinese medicines plays pivotal role in preventing and curing diseases. Sanzi Yangqin Decoction (SYD) is a commonly used prescription for the treatment of cough, asthma and some other respiratory diseases for hundreds of years in practice. This reminds us that there may exist some bioactive compounds strongly binding with the recognized receptors mediating these diseases like β2-adrenegic receptor (β2-AR). Therefore, this work intends to screen bioactive compounds from SYD and revealed the binding mechanism by immobilized β2-AR chromatography and molecular docking. Taking advantages of a 3-high based enzymatic trans-methylation reaction (high speed, high specificity and high activity), the immobilization of β2-AR was successfully achieved. Representative chromatographic peaks of SYD on the immobilized β2-AR column was collected and recognized as rosmarinic acid and sinapine thiocyanate. Tension changes of the trachea ring showed that the two compounds were in a concentration-dependent manner when exerting their effects and the concentration ranges were 10-9-10-4 mol/L and 10-12-10-7 mol/L, respectively. Molecular docking revealed Ser203, Ser204, Ser207, Tyr316 and Asn312 were the main residues for the two compounds to bind with β2-AR. We concluded that the proposed method is becoming an alternative in rapid recognizing bioactive compounds from complex matrix.