Screening and identification of permeable components in a combined prescription of Danggui Buxue decoction using a liposome equilibrium dialysis system followed by HPLC and LC–MS

A new method, i.e., liposome equilibrium dialysis followed by HPLC and LC-MS analysis, has been developed for the screening of permeable components in combined prescriptions of Danggui Buxue decoction (CPDBD). Multiple permeable components were simultaneously predicted by comparison of chromatograms of CPDBD extract before and after interaction with liposome membranes. A diode-array detector (DAD) and an evaporative light scattering detector (ELSD) were used, and the permeable compounds were identified by comparison with the available reference compounds and confirmed by on-line LC-MS. About fifteen compounds in a CPDBD extract were found to interact with liposome membranes. They were identified as calycosin-7-O-beta-D-glucoside (1), senkyunolide I or H (2), ononin (3), (6alphaR,11alphaR)-9,10-dimethoxypterocarpan-3-O-beta-D-glucoside (4), (3R)-2'-hydroxy-3',4'-dimethoxyisoflavan-7-O-beta-D-glucoside (5), calycosin (6), astragaloside IV (7), isoastragaloside II (8), formononetin (9), (6alphaR, 11alphaR),-3-hydroxy-9,10-dimethoxypterocarpan (10), (3R)-7,2'-dihydroxy-3',4'-dimethoxyisoflavan (11), astragaloside I (12), isoastragaloside I (13), E-ligustilide (14), and Z-ligustilide (15), respectively. Among all permeable components, 1, 3, 6, and 9 (flavonoids), 2, 14, and 15 (phthalides), and 7 (saponins) have been considered as major bioactive components in CPDBD. Therefore, this new method appears useful as a first step in the screening of bioactive components in natural products including Traditional Chinese Medicines (TCMs).