Simultaneous determination of 13 representative saponins from the total saponins of Gynostemma pentaphyllum in rat plasma using LC-MS/MS for pharmacokinetic study

Abstract

As a plant with a rich history of medicinal and dietary use, Gynostemma pentaphyllum (Thunb.) Makino is predominantly characterized by the gypenosides. Contemporary research has demonstrated that these saponins possess significant hypolipidemic and hypoglycemic effects. This study focused on developing an LC-MS/MS approach to elucidate the pharmacokinetic profiles of 13 gypenosides in rat models. The separation was accomplished using a ZORBAX Eclipse Plus C18 column (2.1 mm × 100 mm, 1.8 µm). Detection was facilitated by employing positive electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode. The analytical method was fully validated, including selectivity, linear response, measurement precision, analytical accuracy, extraction efficiency, matrix interference, and sample stability. The lower limit of quantification (LLOQ) for all compounds was 10 ng/mL, with each exhibiting a favorable linear relationship (r ≥ 0.9960). The precision, as measured by the relative standard deviation (RSD) for intra-day and inter-day variability, did not exceed 8.41 %. The accuracy, expressed as the relative error (RE), varied from −4.42–8.42 %. The recovery rate of the extraction process was between 92.02 % and 114.77 %, and no notable matrix effects were detected. The stability of the compounds was confirmed under four distinct storage conditions. Pharmacokinetic results indicated that all analytes displayed rapid absorption, prolonged retention, and slow elimination in rats, and exhibited nonlinear pharmacokinetics at low, medium, and high dosage levels. This study has established a quantification method for 13 gypenosides and successfully applied it to their pharmacokinetic studies in rats, providing a foundation for their further development and utilization.