title: Complete isolation and characterization of silybins and isosilybins from milk thistle (Silybum marianum).
abstract: Complete separation, isolation, and structural characterization of four diastereoisomeric flavonolignans, silybins A (1) and B (2), and isosilybins A (3) and B (4) from the seeds of milk thistle (Silybum marianum) were achieved for the first time using a preparative reversed-phase HPLC method. In addition, three other flavonolignans, silychristin (5) isosilychristin (6) and silydianin (7), and a flavonoid, taxifolin (8) were isolated. Structures, including absolute stereochemistries of 1-4, were confirmed using 2D NMR and CD spectroscopy.
authors.affiliation: Natural Product Laboratory, Chemistry and Life Sciences, Research Triangle Institute, 3040 Cornwallis Road, Research Triangle Park, North Carolina 27709, USA. nck@rti.org, mcw@rti.org
authors.forename: Nam-Cheol
authors.initials: NC
authors.lastname: Kim
authors.forename: Tyler N
authors.initials: TN
authors.lastname: Graf
authors.forename: Charles M
authors.initials: CM
authors.lastname: Sparacino
authors.forename: Mansukh C
authors.initials: MC
authors.lastname: Wani
authors.forename: Monroe E
authors.initials: ME
authors.lastname: Wall
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002942:Circular Dichroism; D005419:Flavonoids / Q000737:chemistry* / Q000302:isolation & purification*; D017705:Lignans / Q000737:chemistry* / Q000302:isolation & purification*; D020944:Silybum marianum / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D013237:Stereoisomerism
chemical_list: D005419:Flavonoids; D017705:Lignans