Pressurized liquid extraction followed by high-performance liquid chromatography for determination of seven active compounds in Cortex Dictamni

A new method based on pressurized liquid extraction (PLE) followed by a sensitive and specific HPLC-DAD analysis is developed for determination of seven compounds in Cortex Dictamni. The operational parameters of PLE, such as extraction solvent, extraction temperature, extraction pressure, static extraction time, flush volume and extraction cycles were optimized, using the extraction efficiencies of dictamnine, obacunone and fraxinellone as targets. The optimized procedure employed MeOH as extraction solvent, 150 °C of extraction temperature, 1500 psi extraction pressure, 5 min of static extraction time, 60% flush volume and the extraction recoveries of the three compounds were nearly to 100% for only one cycle. The following HPLC analysis was performed on a reversed-phase C18 column with methanol–water as mobile phase in gradient manner, detected at 236 and 218 nm. The limits of detection (LOD) and limits of quantification (LOQ) of the seven compounds were in the range of 0.4–15.6 ng and 1.2–38.8 ng. This assay can be readily utilized as a quality control method for Cortex Dictamni and other related medicinal plants.