Development of an analytical method for simultaneous detection of greater celandine and Coleus forskohlii in dietary supplements

Abstract

Greater celandine and Coleus forskohlii are designated as ingredients that require special attention (designated ingredients) under the Food Hygiene Act. In this study, we developed a method for the simultaneous quantitative analysis of coptisine and forskolin in dietary supplements containing the designated ingredients using ultra-high performance liquid chromatography (UHPLC). We also developed a simultaneous qualitative analysis method for coptisine, sanguinarine, forskolin, and isoforskolin in dietary supplements containing the designated ingredients using a UHPLC-quadrupole-Kingdon trap mass spectrometry with photodiode array detector. Extraction of samples was carried out by ultrasonication using methanol as the extraction solvent. An ODS column was used for quantitative and qualitative analyses. Quantitative analysis was performed on a gradient of 10 mmol/L phosphate buffer (pH 3.0)-acetonitrile, and qualitative analysis was performed on a gradient of 10 mmol/L ammonium formate buffer (pH 3.0)-acetonitrile. The recovery test results showed recoveries of between 97.23 and 102.14%; the standard deviation was within 2%, indicating good precision. In the application of our quantitative analysis method to commercial dietary supplements, maximums of 10.71 mg/bottle of coptisine and 27.73 mg/tablet of forskolin were detected. When a product containing 27.73 mg/tablet of forskolin was consumed as indicated on the label, the daily intake of forskolin was 110.92 mg. In the qualitative analysis, we confirmed the presence of coptisine, sanguinarine and forskolin in the dietary supplements. The isoforskolin content was confirmed except for one product that contained the minimum amount of forskolin.