Screening the anti-allergic components in Saposhnikoviae Radix using high-expression Mas-related G protein-coupled receptor X2 cell membrane chromatography online coupled with liquid chromatography and mass spectrometry.

Saposhnikoviae Radix, the dried root of Saposhnikoviae divaricata, is commonly used in the traditional Chinese anti-allergic preparations, like Bofutsusho-san and Yupingfeng granules. A high-expression Mas-related G protein-coupled receptor X2 cell membrane chromatography coupled online with high-performance liquid chromatography combined with an ion trap time-of-flight multistage mass spectrometry system was established and used for screening and identifying the anti-allergic components in Saposhnikoviae Radix. The system was validated for excellent specificity and suitability using the appropriate standards. Two retained fractions were obtained on the cell membrane chromatography column, and three main components were identified as prim-O-glucosylcimifugin, cimifugin, and 4'-O-β-d-glucosyl-5-O-methylvisamminol. Next, the molecular docking study was conducted, which confirmed that these three components could effectively bind to MRGPRX2 through hydrogen bonds with its amino acid residues. Finally, histamine release assay was performed to investigate the bioactivities of prim-O-glucosylcimifugin, cimifugin, and 4'-O-β-d-glucosyl-5-O-methylvisamminol. Results showed that these three components could exert anti-allergic effects by inhibiting the histamine release in a dose-dependent manner (from 10 to 100 µM). In conclusion, the high-expression Mas-related G protein-coupled receptor X2 cell membrane chromatography is an effective tool for discovering the anti-allergic components in Saposhnikoviae Radix.