A rapid ultra-performance liquid chromatography-electrospray ionisation mass spectrometric method for the analysis of saponins in the adventitious roots of Panax notoginseng

Introduction - Saponins are bioactive compounds employed in the prevention and treatment of cardiovascular and cerebrovascular diseases. The adventitious roots of Panax notoginseng may offer an alternative source of saponins. Identification and determination of saponins in the crude extract is challenging owing to their similar structures and the lack of standards. Objective - To develop a rapid, sensitive and accurate method based on solid-phase extraction followed by ultra-performance liquid chromatography-electrospray ionisation mass spectrometry (UPLC-ESI-MS) for the identification and quantification of saponins in P. notoginseng. Methodology - Following extraction using Waters Oasis™ HLB cartridges, the analytes were subjected to a UPLC system with a Waters Acquity BEH C₁₈ chromatographic column and a binary mobile phase system consisting of 0.05% formic acid in water and acetonitrile under gradient elution conditions, with final detection by ESI-MS in the positive ion mode. Results - The UPLC-ESI-MS method gave limits of detection and quantification within the range 0.015-0.382 and 0.052-1.124 μg/mL, respectively, for 15 studied saponins. The instrumentation/injection precision (RSD) was 4.5% for a low concentration and 3.2% for an intermediate concentration sample. The intra- and inter-day repeatability was less than 2.65% (RSD). The method described was validated using spiked samples with different amounts of saponin standards. Conclusion - This UPLC-ESI-MS assay provides a suitable quality control method for the tentative identification and determination of major biological active constituents in adventitious and native roots of P. notoginseng.