Abstract

Recently, ultra-performance liquid chromatography (UPLC) has proven to be one of the most promising developments in the area of high-speed chromatographic separations with increased sensitivity and resolution. In this work, a reverse phase chromatographic method was developed using UPLC for the chemical fingerprint analysis of 12 hoodigosides, related genera and dietary supplements. The method is also used for the quantification of P57 in Hoodia species and dietary supplements that claim to contain Hoodia. The analysis was performed on a Waters Acquity UPLC system with an Acquity UPLC BEH C18 column (100 mm x 2.1mm I.D., 1.7 microm) and a gradient elution of water and acetonitrile, both containing 0.05% formic acid with a run time of 15 min. The calibration curve of P57 showed good linearity (r(2)>0.999) within the established range (1-100 microg/mL). The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.3 and 0.9 microg/mL, respectively. The RSD for intra- and inter-day were less than 3.0%, and the recovery efficiency as 97-103%. LC-mass spectrometry coupled with electrospray ionization (ESI) interface method is described for the identification of P57. The developed method was successfully applied to the identification of 12 oxypregnane glycosides in four different species of Hoodia, 23 related genera and 35 dietary supplements that claim to contain H. gordonii. The UPLC profiles of various plant samples were compared for the presence of oxypregnane glycosides. Different sample matrices were successfully analyzed, providing the wide range of applicability of this method, including gels, capsules, tablets, sprays, tea bags, snack bars, powders and juices.