Separation and identification of the fifteen constituents in forsythiae fructus

Abstract

Forsythiae Fructus, a commonly used Chinese herbal medicine derived from the dried seeds of Oleaceae plants, contains rengyoside B (1), matairesinol (2), salidroside (3), quercitrin (4), suspensaside (5), rengyoside C (6), matairesinoside (7), forsythiaside (8), pinoresinol-β-D-glucoside (9), cornoside (10), acteoside (11), arctigenin (12), arctiin (13), phillyrin (14) and pinoresinol (15) as its major bioactive constituents. In this study, a high performance liquid chromatography (HPLC) method using a Cosmosil 5C18-AR II column, and a mixture of phosphate solution and methanol-acetonitrile as the mobile phase with detection of absorbance at 254 or 280 nm was developed to successfully resolve these 15 compounds within 60 min. Peaks were identified by matching the UV spectra and MS information with those of authentic standards or literature data. The method was applicable to LC-MS if the phosphate was replaced with an acetate solution. Calibration curves for 4 of the 15 constituents were obtained around a concentration range of 2 orders of magnitude and showed good linearity. The reproducibility (RSD) of the proposed method was 0.23-1.50% (intraday) and 0.41-2.40% (interday). The detection limits (S/N = 3) for the constituents were determined to be 0.16-0.27 μg/mL.