title: Isolation and purification of diastereoisomeric flavonolignans from silymarin by binary-column recycling preparative high-performance liquid chromatography.
abstract: Silymarin extracted from Silybum marianum (L.) Gaertn consists of a large number of flavonolignans, of which diastereoisomeric flavonolignans including silybin A and silybin B, and isosilybin A and isosilybin B are the main bioactive components, whose preparation from the crude extracts is still a difficult task. In this work, binary-column recycling preparative high-performance liquid chromatography systems without sample loop trapping, where two columns were switched alternately via one or two six-port switching valves, were established and successfully applied to the isolation and purification of the four diastereoisomeric flavonolignans from silymarin. The proposed system showed significant advantages over conventional preparative high-performance liquid chromatography with a single column in increasing efficiency and reducing the cost. To obtain the same amounts of products, the proposed system spends only one tenth of the time that the conventional system spends, and needs only one eleventh of the solvent that the conventional system consumes. Using the proposed system, the four diastereoisomers were successfully isolated from silymarin with purities over 98%.
authors.affiliation: Department of Pharmaceutical Analysis, School of Pharmacy, Second Military Medical University, Shanghai, P.R. China; Shanghai Key Laboratory for Pharmaceutical Metabolite Research, Shanghai, P.R. China; Shanghai Research Centre for Drug (Chinese Materia Medica) Metabolism, Shanghai, P.R. China.
authors.forename: Weiquan
authors.initials: W
authors.lastname: Zhao
authors.forename: Guang
authors.initials: G
authors.lastname: Yang
authors.forename: Fanyi
authors.initials: F
authors.lastname: Zhong
authors.forename: Nan
authors.initials: N
authors.lastname: Yang
authors.forename: Xin
authors.initials: X
authors.lastname: Zhao
authors.forename: Yunpeng
authors.initials: Y
authors.lastname: Qi
authors.forename: Guorong
authors.initials: G
authors.lastname: Fan
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000302:isolation & purification*; D044947:Flavonolignans / Q000737:chemistry / Q000302:isolation & purification*; D020944:Silybum marianum / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D004365:Drugs, Chinese Herbal; D044947:Flavonolignans
keywords: Column switching; Flavonolignan; Recycling preparative chromatography; Silymarin