title: Evaluation of major active components in St. John's Wort dietary supplements by high-performance liquid chromatography with photodiode array detection and electrospray mass spectrometric confirmation.
abstract: A RP-HPLC method with photodiode array detection and LC-electrospray ionization (ESI) MS confirmation was established for the determination of major active components in St. John's Wort dietary supplement capsules. The samples alternatively were extracted with ethanol-acetone (2:3) using a 55 degrees C water-bath shaker or an ambient temperature ultrasonic bath. Extracts were separated by RP-C18 chromatography using a 95-min water-methanol-acetonitrile-trifluoroacetic acid gradient. The major components were identified by photodiode array detection and then confirmed by LC-ESI-MS. The quantification of components was performed using an internal standard (luteolin). This method may serve as a valuable tool for the quality evaluation of St. John's Wort dietary supplement products.
authors.affiliation: US Food and Drug Administration, National Center for Toxicological Research, Division of Chemistry, Jefferson, AR 72079, USA.
authors.forename: F F
authors.initials: FF
authors.lastname: Liu
authors.forename: C Y
authors.initials: CY
authors.lastname: Ang
authors.forename: T M
authors.initials: TM
authors.lastname: Heinze
authors.forename: J D
authors.initials: JD
authors.lastname: Rankin
authors.forename: R D
authors.initials: RD
authors.lastname: Beger
authors.forename: J P
authors.initials: JP
authors.lastname: Freeman
authors.forename: J O
authors.initials: JO
authors.lastname: Lay
mesh_terms: D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D019587:Dietary Supplements / Q000032:analysis*; D020902:Hypericum / Q000737:chemistry*; D010946:Plants, Medicinal; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet