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

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°C water-bath shaker or an ambient temperature ultrasonic bath. Extracts were separated by RP-C 18 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.