Screening vasoconstriction inhibitors from traditional Chinese medicines using a vascular smooth muscle/cell membrane chromatography-offline-liquid chromatography-mass spectrometry

We developed an analytical method for screening vasoconstriction inhibitors from traditional Chinese medicines (TCMs) by combining vascular smooth muscle/cell membrane chromatography (VSM/CMC) with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Primary cultured VSM cells from rat thoracic aortas were used for preparation of the stationary phase of the VSM/CMC column. Retention fractions from the VSM/CMC column were collected and then analyzed by LC-MS/MS under the optimized conditions offline. The suitability and reliability of the VSM/CMC-offline-LC-MS/MS method was assessed using nitrendipine and nifedipine as positive controls, and this method was then applied to screen vasodilator components from the extracts of Fructus Schisandrae Chinensis (FSC) and Fructus Schisandrae Sphenantherae (FSS). The major components from both species retained by VSM/CMC were identified as deoxyschizandrin (DSD) and schisantherin A (STA) by LC-MS/MS. Competition experiments indicated that DSD and nifedipine bound competitively to membrane receptors, while DSD and STA had partly overlapping binding sites on VSM-cell membranes. In vitro pharmacological trials confirmed that STA and DSD could dose-dependently relax the rat thoracic aortas pre-contracted by KCl. Our VSM/CMC-offline-LC-MS/MS method can be applied for screening vasoconstriction inhibitors from TCMs collected from FSC and FSS, and may be useful in the development of vasodilators from natural products.