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 ioniza tion (ESI) MS confirmation was established for the determination of major a ctive components in St. John's Wort dietary supplement capsules. The sample s alternatively were extracted with ethanol-acetone (2:3) using a 55 degree s C water-bath shaker or an ambient temperature ultrasonic bath. Extracts w ere separated by RP-C-18 chromatography using a 95-min water-methanol-aceto nitrile-trifluoroacetic acid gradient. The major components were identified by photodiode array detection and-then confirmed by LC-ESI-MS. The quantif ication 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. (C) 2000 Published by Elsevier Sci ence B.V.